U-- 
 WARMING AND VENTILATING; 
 
 WITH 
 
 DIRECTIONS FOR MAKING AND USING 
 
 THE 
 
 THERMOMETER-STOVE, 
 
 OR 
 
 SELF-REGULATING FIRE, 
 
 AND 
 
 OTHER NEW APPARATUS. 
 
 BY NEIL ARNOTT, M.D., 
 
 *^s^ 
 
 PHYSICIAN EXTRAORDINARY TO THE QUEEN, 
 
 Author of the " Element! of Phytiti," iff. 
 
 LONDON: 
 
 LONGMAN, ORME, BROWN, GREEN, AND LONGMANS, 
 PATERNOSTER ROW. 
 
 1838.
 
 Printed by J. L. Cox and Sons, 75, Great Queen Street, 
 Lincoln's-Inn Fields.
 
 ' TH 
 
 ADVERTISEMENT. 
 
 THE following Treatise contains the substance of a Lec- 
 ture delivered before a scientific audience at the Royal In- 
 stitution on the llth March 1836, and which is now, by the 
 addition of elementary illustration, fitted for popular use. 
 
 My reasons for not publishing it sooner were first, that, 
 in a matter of such importance to this and other countries, 
 as the obtainment of necessary warmth, from failure with 
 respect to which, and to ventilation, much of the suffering 
 and many of the diseases which afflict the inhabitants arise, 
 I might, in recommending changes, have to report the 
 result, not of one or two experiments only, but of many, 
 carried on under great variety of circumstances, and in all 
 the seasons of the year. Secondly, that I might, by wider 
 observation and discussion, be better prepared to make evi- 
 dent to popular apprehension certain misconceptions or 
 prejudices which have hitherto prevented the introduction 
 of better methods, and to explain to makers of the new 
 apparatus what would be required of them. I know that, 
 owing to the delay of the publication, not a few imperfect 
 stoves have been made, by persons little acquainted with 
 scientific principles, and who therefore needed, for constant 
 reference, written directions as minute and precise as are
 
 IV 
 
 here given. But to have prepared such directions for any one 
 maker, rendering myself responsible for his performance, 
 would have cost me nearly as much time, which I could il\ 
 spare, as to prepare this book, which is to serve as a guide to 
 all. I therefore declined doing so, and advised persons gene, 
 rally to wait for the publication of the book. 
 
 My reason for delivering the lecture before I had the 
 book fully prepared, was, that as I had decided not to 
 reserve for myself any patent right in the new apparatus, I 
 might, by having numerous competent witnesses of what I 
 had proposed and accomplished, prevent other parties who 
 might hear of my processes from appropriating them by 
 patents, and thus coming between me and the public. 
 
 Because several of the new means, and particularly the 
 thermometer stoves, are of the nature of the things for 
 which patents are usually taken, friends had urged me 
 strongly to follow the custom representing that the Legisla- 
 ture of this country has devised the patent alone as a mode 
 of remunerating the proposers of useful inventions ; and that 
 many honoured names, as lately, of Watt, Arkwright, Wol- 
 laston, &c., are in the list of those who have profited by the 
 law ; and further, that in the case of the stove, it would be 
 an advantage to the public that I should retain the right of 
 naming the persons allowed to manufacture it, thereby to 
 prevent such disappointments from imperfect workmanship, 
 as happened in some cases with regard to my hydrostatic bed, 
 and other suggestions strictly professional. 
 
 I had decided not to take the patent ; because the stove 
 was originally planned as a means of preventing and curing 
 diseases, pin-poses for which it will always be important, 
 whatever other advantages be derived from it ; and in this 
 country it is usual for members of the medical profession 
 to make an offering at once to the public of any means 
 for the benefit of the general health which they may dis- 
 cover or devise, without stipulating for private advantage.
 
 Then, although I believe I might have better served the 
 public by keeping control over the sale of the floating bed, 
 I think, in regard to the stove, that the construction and 
 management will by this publication be rendered so intelli- 
 gible to all, that mistakes can scarcely happen ; and it is 
 likely that the wide competition among the talented men 
 about to engage in the manufacture, will sooner lead to the 
 adoption of the best and cheapest forms and construction, 
 than if the business had remained in fewer hands 
 
 Since I gave my Lecture, and publicly described the ther- 
 mometer-stove, I have heard of various supposed improve- 
 ments on it, and substitutes for it, but no one has come to 
 useful maturity. In London, within a few weeks, a new 
 stove has been exciting curiosity, although its nature has 
 not been disclosed, and I am induced to notice it here 
 because many persons have been confounding it with the 
 thermometer-stove. In the body of this work is described a 
 modification of the thermometer stove, adapted to wann 
 carriages, Sec., or to be immersed in a bath, to warm it : 
 which modification may be of any size, from that of a quart 
 jug upwards, standing on a support, or suspended like a 
 lamp, with a small tube to carry away the smoke, or gases 
 of the combustion, and which will maintain, like the other 
 forms of the stove, an unvarying temperature for twenty- 
 four hours, or more, without being watched or touched, at 
 an expense of a penny or two-pence, according to the size. 
 The new stove alluded to I haye heard described in nearly 
 the same terms. It is not said of it, however, that the heat 
 is uniform ; and the expense of fuel, for even a small one, 
 has been estimated at a farthing an hour, which is much 
 more than for a large thermometer-stove. Then it is stated 
 of it, that a stove of three or four feet surface is sufficient 
 to warm an ordinary room, such as we know to require 
 sixteen or twenty feet surface of ordinary iron pipe or 
 othervessel containing boiling water : now this can be true
 
 VI 
 
 only if the temperature of the smaller vessel be propor- 
 tionally higher ; and we know that a temperature in it but 
 a little higher than that of boiling water, would render its 
 presence in a sitting-room insufferable, from its injuring the 
 air which touched p it. Then it is to be used without a 
 chimney ; but evidently, if there be combustion in it of 
 any kind, the aerial products of combustion, always noxious 
 to animal life, must spread in the room. And lastly, if 
 there be no combustion in it, but merely a heating by ordi- 
 nary chemical action, as when water is dropped on quick- 
 lime, there will be comparatively little heat, and the heat will 
 cost dear, and the apparatus will not be applicable to many 
 of the purposes of a fire. But to decide aright respecting it, 
 we must know what it is. 
 
 BEDFORD SQUARE, 
 1 4th January 1838.
 
 CONTENTS. 
 
 Page 
 
 Advertisement iii 
 
 Introduction 1 
 
 Ventilating 14 
 
 Warming - 15 
 
 Fire in the open air , 19 
 
 under cover 20 
 
 a chimney ib. 
 
 Close Stoves 28 
 
 Heating by Steam 30 
 
 Hot water 36 
 
 Hot air 37 
 
 Thermometer Stove 39 
 
 Ventilation 56 
 
 by double current 67 
 
 Giving moisture to air 73 
 
 Warming and Ventilating, in 
 
 Ordinary rooms 76 
 
 School-rooms 83 
 
 Courts of Law 85 
 
 Churches ib. 
 
 Houses of Parliament 86 
 
 Theatres 89 
 
 Hospitals ib. 
 
 Cotton Factories 90 
 
 Hothouses , 91 
 
 Zoological Gardens ib. 
 
 Making uniform Climate for Invalids 90 
 
 Safety Lights for Mines 92 
 
 Ventilating Railroad Tunnels 96
 
 Vlll 
 
 Page 
 
 Manufacturing of the Thermometer Stoves 97 
 
 Of Heat Governors 104 
 
 Fixing the Stoves 125 
 
 Using the Stoves 127 
 
 Common errors in 
 
 Manufacturing 131 
 
 Fixing 133 
 
 Using 134 
 
 Conclusion 135
 
 ON 
 
 VENTILATING AND WARMING. 
 
 INTRODUCTION, 
 
 Article 1. THAT a man of sound constitution, 
 and who remains-uninjured by poisons or violence, 
 may have uninterrupted health for the full period 
 of human life, there are only four things or con- 
 ditions which he can ever be required himself to 
 provide or secure ; namely, fit AIR, WARMTH, 
 ALIMENT, and EXERCISE of his bodily and men- 
 tal faculties. These four, evidently, are not more 
 necessary to him than the place of his abode, this 
 great earth itself, with the harmonious laws of 
 nature, mechanical, chemical, and vital, which 
 determine its state and changes ; but as none of 
 the last noted particulars are in any way depen- 
 dent on him, or can ever be wanting where he is, 
 the other four, of which the procurement often 
 demands his special attention, may be conve- 
 niently distinguished as his great " necessaries of 
 life" the same four, it may be remarked, being 
 equally necessary to inferior animals. Now, of 
 these four, in regard to man, it is true, 1st, that 
 the total privation of any one quickly extinguishes 
 life ; 2dly, that the deficiency, excess, or other 
 
 B
 
 2 INTRODUCTION. 
 
 misgovernment, injures the perfect life, or health, 
 producing all the disturbed states called diseases, 
 except such as arise from poisons and violence ; 
 3dly, that in modified management of them are 
 found the most important remedies in all cases of 
 disease ; 4thly, that they, in conjunction with 
 poisons and violence, constitute the primary 
 sources of human pleasures and pains, and are, 
 directly or indirectly, the general motives of 
 human actions or conduct. The knowledge of 
 some of these truths has been slowly acquired by 
 man. We shall review them separately. 
 
 2. The total want or privation of the four neces- 
 saries quickly extinguishes life. In regard to air, we 
 see the instant suffocation of a man whose breathing 
 is in any way prevented ; in regard to warmth, 
 the perishing of persons overwhelmed far from shel- 
 ter in a snow-storm; in regard to aliment, the 
 deaths, common in barbarous countries, of prisoners 
 shut up without food ; and in regard to exercise 
 of the faculties, the speedy fate of active persons 
 suddenly deprived of liberty and occupation, or 
 of wild animals too closely confined in cages. Of 
 the first necessary, air, the supply cannot be 
 dispensed with, even for a few minutes ; witness 
 the suddenness of drowning, of suffocation from 
 any azotic gas breathed, or from any mode of 
 strangulation ; and the fact that the most practised 
 pearl-fisher, or other diver, can barely remain 
 two minutes under water. Of the second neces- 
 sary, warmth, the ordinary supply or means for 
 retaining what is in the body, may be withdrawn 
 for a longer time without fatal result, as in cases
 
 INTRODUCTION. 3 
 
 where persons have lain in a snow-wreath for 
 an hour or more, benumbed or insensible, but 
 yet have been restored to animation by suitable 
 means ; although possibly the feet and hands, or 
 other parts distant from the heart, have been 
 so completely frozen as afterwards to drop off. 
 Very intense cold, however, kills the whole body 
 quickly, as happens to any animal exposed 
 naked to an atmospheric temperature capable of 
 freezing mercury, or thrown into a freezing mix- 
 ture, as of snow and salt. During the retreat of 
 Buonaparte's army from Moscow in the year 1812, 
 in one night when the thermometer suddenly fell 
 to 19 below zero, thirty thousand horses perished, 
 and a number of the men so appalling, that it 
 never was declared. Proving the suddenness of 
 the catastrophe, many of the stiffened corpses of 
 the men were found next morning around the 
 extinct ashes of the night fires, still in the sitting 
 posture, with hands extended as if to be warmed. 
 Of the third necessary, aliment, the total want 
 has been borne, in some cases, for many days, 
 and sometimes even for weeks, before the horrible 
 death arrived, as proved by the records of ship- 
 wrecks, sieges, famines, and similar calamities. 
 Of the last necessary, exercise, or use of the 
 parts and faculties, the privation can never be 
 rendered so complete, as to show at once the fatal 
 result; but the consequences of want, in com- 
 mon degrees, are seen in the broken health and 
 shortened lives of the idle, indolent, and solitary. 
 3. Mismanagement in regard to the four neces- 
 saries .produces disease and premature death . First, 
 B 2
 
 4 INTRODUCTION. 
 
 in regard to AIR, or the changing supply of it 
 called ventilation. In the crowded and ill-venti- 
 lated apartments of many manufacturing opera- 
 tives, as of cotton-spinners, weavers, lace-workers, 
 milliners, and among pauper-school children, &c., 
 the individuals confined have been observed soon to 
 become pallid, thin and weak, and, before long, to 
 exhibit all the forms of scrofulous disease, as 
 glandular swellings, enlarged joints, bowel dis- 
 orders, consumptions, &c., sinking many of them 
 into early graves ; and where crowding and filth 
 have been great, as common not long ago in ships, 
 prisons, barracks, hospitals, &c., often very ma- 
 lignant fevers or plagues sprang up. Secondly, 
 in regard to heat and the artificial supply of it, 
 catted warming. From the defect, excess, or 
 sudden changes of heat, numerous hosts of dis- 
 eases arise for instance, in temperate climates, 
 those called winter diseases, as catarrhs, influenzas, 
 inflammations, rheumatisms, chilblains, and in 
 part consumptions ; and those called summer 
 diseases, as biliary disturbances, cholera, certain 
 fevers, &c. Then there are tropical diseases, as 
 liver affections, dysentery, yellow and jungle 
 fevers, strokes of the sun, &c.; and boreal diseases, 
 as frost-bitten feet, noses, &c. Thirdly, in regard 
 to aliment, of which, however, it does not belong 
 to the plan of this essay to speak at length, 
 we may notice, the diseases from deficiency 
 arising during famines, as putrid fevers, scurvy, 
 dropsies, &c. ; others, which arise from excess, 
 as inflammations, hemorrhages, apoplexies, others, 
 from improper kinds, as sea-scurvy, gangrene,
 
 INTRODUCTIOX. 5 
 
 cancers, ulcer. Fourthly, in regard to exercise, 
 of which also it is beyond our province to speak 
 particularly, we may shortly observe that faulty 
 management favours the production of many of 
 the diseases already mentioned, besides inde- 
 pendently producing others, as dyspepsia, gout, 
 head-achs, obesity, &c. -Under the two heads of 
 poisons and violence, which produce all the 
 diseases and deaths not caused by mismanagement 
 in regard to the four necessaries of life, there are 
 to be ranged under the first, besides the mineral 
 poisons of arsenic, corrosive sublimate, &c., and 
 the vegetable poisons of opium, hemlock, &c., 
 and animal poisons, as venom of snakes, of mad 
 dogs, &c. ; also the small number which spread 
 from person to person by contagion, as small- pox, 
 measles, hooping-cough and the mixture of poi- 
 sons in the malaria of marshes, and in filth gene- 
 rally. Under the head of violence come contusions, 
 fractures, cuts, burns, and effects of lightning. 
 "Whoever will take the trouble to review the list of 
 human diseases, will find them all belonging to 
 the classes now described, and will perceive, as 
 was stated in the beginning, that any person who 
 has originally a sound constitution, and escapes 
 the action of poisons and violence, and uses 
 always aright the four necessaries of life, must 
 attain a hale old age. 
 
 4. While faulty management in regard to the 
 necessaries, is thus the chief cause of the great 
 mass of diseases, peculiarly modified management of 
 them becomes the chief part of the cure of all diseases. 
 First, in regard to air, we may cite the striking
 
 INTRODUCTION. 
 
 effects, but lately known, of ventilation, in the 
 treatment of small-pox, measles, and fevers gene- 
 rally ; and the effects of pure air in curing, and still 
 more certainly in preventing most of the diseases 
 which formerly infested the great factories and 
 other crowded places. There is a disease among 
 horses, called glanders, a kind of malignant catarrh, 
 in relation to which it is reported that now for 
 some time 10,000 a-year has been saved to the 
 English Government, by a simple plan of venti- 
 lating the cavalry stables. Mere change of air is 
 in many diseases an efficacious remedy ; and in 
 no disease is the want of pure air unimportant. 
 Secondly, in regard to warmth, we need only 
 allude to the necessity of regulating temperature 
 in all sick rooms, and of protecting delicate per- 
 sons at all times by suitable clothing and lodging. 
 The effects of hot and cold bathing, of change 
 of season and of climate, belong to the same 
 head. Thirdly, the management of diet is in all 
 diseases popularly known to be of the greatest 
 consequence : and fourthly, the same is true of 
 the management of exercise, including its negative, 
 rest. Neither of these last-mentioned subjects, how- 
 ever, has to be particularly considered in this essay. 
 5. The four necessaries, with poisons and violence, 
 are the primary or original sources of human plea- 
 sures and pains, and the great motives of human 
 actions. The first manifestations of strong feeling 
 iu a child are its cries when it is cold, hungry, 
 stifled by covering on its face, or oppressed by 
 obstacle to the free motion of its limbs ; that is 
 to say, when it wants any of the four necessaries
 
 INTRODUCTION. 7 
 
 of life ; or, again, when it is bruised, pricked, 
 burned, &c., or is fed improperly ; that is to say, 
 when it suffers from violence, or from what, in 
 the general sense, is poisonous. The other class 
 of manifestations comprises its smiles of happi- 
 ness, when after experiencing wants it is supplied; 
 as when after hunger it gets food, after cold, 
 warmth, &c., or when its faculties are called into 
 exercise, as the sight by vivid colours, the hear- 
 ing by loud sounds, &c. ; and lastly, when it 
 begins to recognise the causes of its pleasures, 
 chiefly in the fond mother herself, or of its 
 pains in other objects, and cries or laughs from 
 recollection or anticipation. Now, not only in 
 infancy, but throughout the whole course of human 
 existence, the due use of the necessaries of life is 
 accompanied by the kind of sensation which we 
 call pleasure, and of which it is our nature to 
 desire the continuance, and to strive to secure the 
 continuance or repetition ; and the deficiency or 
 excess of the necessaries is accompanied by an 
 opposite kind of feeling, called pain, of which we 
 desire and strive to ensure the cessation. These 
 truths are marked by the common language in 
 regard to fit degrees of the necessaries, that we 
 enjoy them, namely, air, warmth, food, drink, 
 and exercise ; which four names, as names of 
 pleasures, are rendered still more expressive by 
 epithets ; as when we say pure air, mild warmth, 
 refreshing or delicious food, and cheering exer- 
 cise : and, again, by the common language in 
 regard to deficiency or excess of the necessaries that 
 we suffer them, namely, suffocation, cold, hunger
 
 INTRODUCTION-. 
 
 or thirst, and ennui, for deficiency ; and heat, sur- 
 feit, fatigue, exhaustion, c. for excess; to which, 
 as names of pains, innumerable characteristic epi- 
 thets are also added. Very young children and the 
 inferior animals, having no knowledge of the uni- 
 rerse, or ideas whatever, but of the sensations 
 above enumerated, and of the most obvious causes 
 or concomitants of these sensations, the list may 
 be held to indicate all the primary pleasures and 
 pains of animated beings. That the same list indi- 
 cates all the motives of action of children and the 
 inferior animals, follows from the fact that there is 
 no voluntary action but to secure an end, of which 
 an idea and desire exist in the mind of the agent. 
 Now that the same four necessaries, or the sensa- 
 tions connected with the supply of the ever- 
 recurring animal wants and the preservation of 
 life, are immediate and all-powerful motives to 
 action also among adult human beings, is seen 
 in such facts as when the famishing victims of 
 shipwreck, regardless of everything else, murder 
 and eat one another, to allay the cravings of 
 hunger, &c. ; and that they are, moreover, the 
 ultimate objects of the whole deliberate business 
 and activity of human individuals and societies, 
 except the little, alas! which regards that other 
 world, the nature of which "nor eye hath seen, 
 nor ear hath heard, nor hath it entered into the 
 mind of man to conceive," is discovered in the 
 fact of the actions which have them not as their 
 immediate aim, being still directed to obtain the 
 means of ultimately securing them. The agricul- 
 tural industry of men, and the manufacturing and
 
 INTRODUCTION. 9 
 
 commercial, have no other views ; as is true also 
 of most of the contentions and crimes ; witness 
 common robberies and murders! The bloody wars 
 among savage tribes are often for the possession 
 of hunting-grounds ; and between mighty nations, 
 deemed civilized, wars have been for fishing- 
 stations, and for colonies supplying food or 
 clothing. But even the secondary or mental 
 pleasures and pains, deemed usually of a higher 
 order, as hope, fear, &c., bear generally upon the 
 same objects, and admit of the same explanation; 
 and when men, singly or in society, are striving 
 to attain knowledge, power, superiority, &c. they 
 generally pursue these as they do cumbrous gold 
 and silver, or other riches, only to obtain more 
 perfect security for the continued supply and en- 
 joyment of the things necessary to their physical 
 existence. Nay, many persons and religious sects, of 
 gross or ignorant minds, have no higher conception 
 of another life and another world, than that then 
 and there they may be able to gratify the physical 
 or sensual desires more deliciously and uninter- 
 ruptedly : they figure to themselves ambrosia, 
 and nectar, and houris, never-failing warmth, and 
 light, seraphic music for the ear, sweet odours for 
 the olfactory sense, &c. &c. in the midst of perfect 
 immunity from all physical pains or ills, and with 
 assurance that the happy state is never to end. 
 
 6. Knowledge of some of the truths above announced 
 has been slowly acquired by man. Returning from 
 such wide speculation as the last paragraph would 
 lead to, we have now to observe, that in the fact 
 of the two powerful sensations called pleasure
 
 10 INTRODUCTION. 
 
 and pain being made to accompany so generally 
 what is good or hurtful to animal nature, there is 
 established, with admirable providence, an instant 
 or immediate motive to every man, and even to 
 every brute creature, to do to a certain extent 
 what is required for the preservation of the health 
 and life of the individual and species. As in all 
 cases, however, the pleasures and pains alluded to 
 do not occur immediately; and in different situa- 
 tions on earth, the kinds and degrees of the 
 necessaries of life suited to particular animal 
 constitutions are not naturally found, brute crea- 
 tures, whose understanding as to how events come, 
 and how things not seen may be artificially gotten 
 or avoided, is weak, have the existence of any 
 species limited to the particular situations on earth 
 where the requisites for its peculiar constitution 
 abound naturally ; so that a creature, for instance, 
 not clothed by nature with fur or other kindred 
 defence, can exist only in climates where such 
 clothing is not required. But man in these 
 respects stands out among animated beings a 
 singular exception. He, although physically con- 
 stituted to require a nice adaptation of the four 
 necessaries, possesses intellectual and other powers 
 which can secure it for him in any part of the 
 earth, and accordingly he lives healthy and happy 
 anywhere, from the equator almost to the pole. 
 
 7. The educated members of civilized com- 
 munities are now well acquainted with the four 
 necessaries of life, and with the means by which 
 these are to be secured, but the knowledge has 
 been very slowly acquired, and is yet very im-
 
 INTRODUCTION. 11 
 
 perfectly diffused among the people. In some 
 tropical countries, such as were probably first 
 inhabited by man, all the requisites exist so per- 
 fectly suited to the human constitution that the 
 easiest efforts of mind and body secure them. 
 The air, in good situations, is ever as pure as on 
 the sea beach ; the warmth is that which, to per- 
 sons unprotected by clothing, is the most agreeable 
 and salubrious ; good food of various kinds is 
 always abundant ; and the requisite exercise is 
 taken in selecting and preparing the food, and in 
 natural pastime. In such a country the people 
 no more think of warmth as a necessary of life than 
 of the gravitation which holds their bodies to the 
 earth. But in other climates, men, in their mid- 
 winter, feel warmth to be not less necessary than 
 food. Thus, the popular acceptation of the term 
 " necessary of life" differs with the climate and 
 degree of intelligence of the people. It would be 
 when portions of the human race spread north or 
 south from a native tropical home that, with 
 changes of season, they would first experience the 
 pain and other consequences of cold, and would 
 learn that warmth was a requisite of life and health. 
 It would be afterwards, when their arts had ad- 
 vanced to the construction of apartments more or 
 less closed to maintain warmth, that they would 
 discover air to be something which might be con- 
 fined, and thereby rendered hurtful to them, and 
 that pure air also was a necessary of life ; and 
 it might be, when differences of rank arose, 
 and placed classes of the community above the 
 necessity of working, that some persons would
 
 INTRODUCTION. 
 
 renounce all labour or exertion, and, by the con- 
 sequences, would find that exercise too was a 
 necessary to well-being. By such steps we may 
 suppose knowledge of the means of preserving 
 health and life to have been gradually obtained. 
 This knowledge has now been perfected by much 
 scientific labour; but so little has it become yet 
 a part of general education, that even in England, 
 where human arts and civilization have advanced, 
 as far at least as any where on earth, the average 
 duration of human life, which depends on the 
 management of the circumstances enumerated, is 
 scarcely half of what the human constitution 
 allows. We know, however, that great improve- 
 ment has recently taken place, and is yet rapidly 
 advancing, and that in situations, for instance, 
 where formerly bad ventilation and ill-regulated 
 temperature had produced the hosts of scrofulous 
 diseases, and of diseases from faulty temperature, 
 the population is now comparatively healthy. 
 
 8. Stronger evidence of what, in respect to 
 general health and long life, is within human 
 power, can scarcely be obtained, than by com- 
 paring the accurately-recorded rates of mortality, 
 or value of human life, in England, at various 
 periods of past time, and at the present. For 
 example: in the five plagues, or epidemics, 
 which occurred in London during the seventy- 
 three years from 1592 to 1665 inclusive, after the 
 last of which came the great fire of 1666, which 
 led to the rebuilding of a large part of the city, 
 and to the disappearance of such plagues all 
 which five plagues we know to have been fostered,
 
 INTRODUCTION. 13 
 
 if not entirely produced, by the impure condition 
 of the town, the average deaths in each year of 
 plague amounted to very nearly a fourth part of 
 the whole population. This, for the present 
 population of London, would be about 375,000 
 persons in one year. Now the present annual 
 mortality in London being about 42,250, and the 
 deaths in the year of the late cholera, which was 
 the most severe plague which has visited London 
 since 1666, having been only 48,500, making a 
 loss by the plague of only one person for every 
 250 of the population, we see a prodigious decrease 
 of mortality; under a like visitation of a malignant 
 epidemic, owing, there can be no doubt, to the 
 improved condition of the city in respect to 1st. 
 purity of air, as dependant on wider and cleaner 
 streets, good drainage, and better supply of water; 
 2dly. to improved supply of fuel, and better 
 construction of the houses ; 3dly. probably, in 
 some degree, to better food and more healthful 
 habits. Such havoc as formerly occurred in Lon- 
 don from plagues has been lately again witnessed 
 from the Asiatic or malignant cholera, in many of 
 the old unimproved cities of Europe, and strik- 
 ingly, everywhere, in proportion to the remaining 
 defects. We shall have occasion to show, that, 
 even in London, there is still room for much im- 
 provement in the art of securing health. 
 
 9. The object of this essay is to render the know- 
 ledge on the subjects of ventilation and warming 
 which now exists among the learned, familiar to 
 all, and to introduce to public notice new and 
 simple means of securing the ends in view.
 
 14 
 
 ON VENTILATION. 
 
 10. Ventilation is the process of changing, any 
 where, air which has been rendered impure. The 
 chief cause of impurity is the respiration of persons 
 in the place. In respiration or breathing, a man 
 draws into his chest at one time, about twenty 
 cubic inches of air, and of that air a fifth part is 
 oxygen, of which again there is converted into car- 
 bonic acid gas nearly a half. The carbonic acid 
 if afterwards inhaled, would be noxious to the 
 individual. About fifteen inspirations are made 
 in the minute, vitiating therefore 300 cubic 
 inches, or nearly one-sixth of a cubic foot of 
 atmospheric air, but which, mixing as it escapes 
 with several times as much, renders unfit for re- 
 spiration at least two cubic feet under common 
 circumstances. The removal of this impure air, 
 and the supply in its stead of fresh air, is per- 
 fectly accomplished by an uninterrupted natural 
 agency. The air which issues from the chest 
 being heated to near the temperature of the body, 
 or 98 a , and therefore dilated, is specifically 
 lighter than the surrounding air at any ordi- 
 nary temperature, and therefore ascends in the 
 atmosphere to be diffused there, as oil set free 
 under water rises in it to spread above : in both 
 cases a heavier fluid, in fact, pushing up and 
 taking the place of, a lighter. This beautiful pro- 
 vision of nature, without trouble to the party, or 
 even his being aware of it, is relieving him at every 
 instant from the presence of a deadly, though in- 
 visible poison, and replacing it with pure, vital
 
 ON VENTILATION. 15 
 
 sustenance; and the process continues while he 
 sleeps as while he wakes, and is as perfect for the 
 unconscious babe, or even brute creature, as for the 
 wisest philosopher. The process may be called 
 natural ventilation, and in the open atmosphere, 
 while the wind blows, and air is as uninterruptedly 
 passing the person, as the water of a mountain- 
 stream is passing its finny inhabitants, the pro- 
 cess is perfect. Where men, however, construct 
 apartments which shut up or confine air, the 
 action is disturbed. But even then, some degree 
 of the same change always takes place by the 
 escape through the crevices and joinings about 
 windows, doors, &c. of a portion of the warmed 
 air, to be replaced by fresh air entering below. 
 And it is this natural ventilation of rooms, which 
 by effecting the purpose to a certain degree, has 
 prevented the mass of mankind from discovering 
 the want of any other. Such accidental ventila- 
 tion, however, is very irregular and imperfect, and 
 to remedy the defect, not a little art is in many 
 cases required. The artificial means of ventilation 
 now alluded to are often intimately connected with 
 the means of warming; and it will render the 
 explanation of the whole easier, to treat of the 
 warming first. 
 
 ON WARMING. 
 
 11. All animal bodies require to exist in a 
 certain temperature, which in those called warm- 
 blooded, is considerably higher than of the sur- 
 rounding atmosphere; and by the actions of life 
 they maintain in themselves that which to each is
 
 16 ON WARMING. 
 
 suitable. This continues very nearly uniform, not- 
 withstanding considerable fluctuations in the tem- 
 perature of the air and of other objects around 
 them. In man the animal heat is of 98 of Fahren- 
 heit, whether under the burning sun of India, or 
 amidst the snows of the pole. The animal heat is 
 maintained above lower surrounding temperatures 
 chiefly by the function of respiration, in which 
 the oxygen of the air, received into the lungs, 
 combines by a kind of slow combustion with carbon 
 from the blood, and gives out heat, nearly as when 
 oxygen and carbon combine in a common fire- 
 This focus of heat suffices to maintain the healthy 
 temperature even in a naked body, in air at from 
 60 to 70, and in bodies clothed with fur or 
 feathers, it will maintain that temperature in air 
 which is very cold indeed. When, on the other 
 hand, the temperature around animals is high, the 
 body relieves itself of its superabundant heat, 
 chiefly by copious perspiration and evaporation 
 from the skin and lungs. To fit the inferior warm- 
 blooded animals for the various climates of the earth, 
 different qualities and thicknesses of hair or feathers 
 are given to them ; but man, as already said, is 
 left to clothe himself according to the necessity; 
 or, with less clothing, he may in any situation make 
 the air of his dwelling of the temperature which 
 suits the kind of clothing which he permanently 
 prefers. In China men prefer to secure themselves 
 against the severe winter colds, chiefly as infe- 
 rior polar animals are secured, by very thick 
 clothing. In Europe they generally prefer to wear 
 in the house more nearly their summer dress, while
 
 ON WARMIXG. 17 
 
 by fires they artificially warm the air to nearly 
 summer temperature. The safer plan of the two, is 
 perhaps, that adopted in China, because the de- 
 fence is as constant and uniform as the season 
 which demands it. And that the human frame, if 
 well clothed, is fitted to breathe, even with delight 
 as well as safety, a very cold air, is proved by the 
 feelings of persons in a warm bed, during a winter 
 morning so cold, as to have frozen any water acci- 
 dentally standing in the room ; or, by the feelings 
 under a clear, but intensely cold winter sky, of 
 children at play, skaiters on the ice, or sportsmen 
 in the field. It would be a good rule for persons in 
 Europe to clothe themselves in winter so as to be 
 comfortable in a room at a temperature of 60 or 
 62, and to let that be the steady temperature of 
 their common apartments, which it could then 
 never be dangerous either to enter or to leave. Now, 
 with common fires in England, rooms are often 
 heated up to 70 or above, and cooled down to 50 
 or below. 
 
 12. While natural warmth then, in relation]to an 
 animal body, is that generated in the body itself, 
 and retained in it more or less by the natural 
 covering counteracting the temperature of the 
 climate; artificial warmth is the modification of 
 the natural, produced by artificial covering called 
 clothing and lodging, and by the agency of com- 
 bustion or fire. The phrase popularly refers to 
 the action of fire ; and we now proceed to describe 
 the nature of fire, and to examine the successive 
 steps by which men have sought to derive the 
 greatest advantage from it.
 
 18 ON WARMING. 
 
 13. Ordinary combustion is chemical union tak- 
 ing place with intense energy, productive of light 
 and heat, between oxygen and some substance to 
 which oxygen has strong chemical attraction. The 
 substances which so combine with oxygen are 
 called combustible, and of these the most common 
 and cheapest, are coal, wood, coke, charcoal, and 
 peat. A quantity of any of these substances heated 
 to ignition, and placed where a current or change 
 of air can reach it, immediately begins to combine 
 with the oxygen of the air and to be dissolved 
 therein and dissipated, with appearance of flame 
 or light, and with powerful generation or disper- 
 sion of heat, in a word, it is said to burn. In.this 
 process constant renewal of fresh air is required, 
 just as for respiration, and is furnished by nature 
 nearly in a similar way, the air heated by contact 
 with the burning fuel quickly and continually 
 ascending to be replaced by fresh air. Of the heat 
 produced in the combustion of coals, a proportion 
 rather less than half is radiated around the fire, as 
 the light is from a fire or from a candle, and rather 
 more than half combines with the air which feeds 
 the combustion and rises with the smoke, to be 
 dissipated in the atmosphere. Experiment has 
 shown, that 
 
 One pound of good coal Melts of ice ... 90 Ibs. 
 
 Coke _"*.. 84 
 
 Wood ... 32 
 
 Charcoal of wood ...95 
 
 Peat ... 19 
 
 indicating, the comparative values of these sub- 
 stances as fuel : and the exact relation is known 
 between the quantity of heat required to melt ice,
 
 OX WARMING. 19 
 
 and to effect other results. The quantity of heat 
 which raises the temperature of a cubic foot of 
 water one degree, being called one, of such ones 
 or units, 140 will melt a cubic foot of ice ; 180 
 will raise the temperature of a cubic foot of water 
 from 32, or freezing, to 212, or boiling tempera- 
 ture ; 960 more will convert that into steam ; and 
 what heats a cubic foot of water 1, will heat 2850 
 cubic feet of common air also 1, or half that quan- 
 tity 2, and so forth. One mode of estimating how 
 much of the heat of a fire radiates around it, and how 
 much combines with the smoke, is to let all the 
 radiant heat melt ice in a vessel surrounding the 
 fire, and all the heat of the smoke melt ice in 
 another vessel surrounding the chimney. The two 
 quantities of water thus obtained, and measuring 
 the quantities of ice melted, prove the radiant 
 portion of the heat to be in ordinary cases rather 
 less than the combined, that is to say, to be less 
 than half of the whole heat produced. 
 
 Afire in the open air. 
 
 14. The first step made by man in the art of 
 warming himself by fire would naturally be, sim- 
 ply to light a fire in some convenient situation in 
 the open air, and to place himself near it. He 
 would in so doing benefit by that portion of the 
 radiant heat which fell on, or was intercepted by, 
 his body ; but the rest of the radiant heat, and 
 the whole of the heat combined with the smoke, 
 would be lost, or dissipated in the atmosphere. 
 Houseless savages still use fire in this way, as do 
 soldiers in their bivouacs. 
 c2
 
 20 - ON WARMING. 
 
 A Jire under cover. 
 
 15. The second step might be to light the fire 
 in a place more or less enclosed. Then, not only 
 would the part of the radiant heat which impinged 
 directly on the bodies of persons present be ren- 
 dered serviceable, but the remainder also, which, 
 falling on the walls and warming them, would be 
 partially reflected ; and moreover, the heat com- 
 bined with the smoke would be for a time retained 
 in the place, and would still further warm the walls 
 and roof, and the bodies of inmates. By such an 
 arrangement, nearly the whole of the heat evolved 
 in the combustion is applied to use ; but it is 
 conjoined with the smoke, or offensive vaporized 
 products of the fuel. The savages of North Ame- 
 rica thus place fires in the middle of the floor of 
 their huts, and sit around in the smoke, of which 
 the excess escapes by the one opening in the hut 
 which serves as chimney, window, and door. 
 A few of the peasantry in remote parts of Ireland 
 and Scotland still place their fires in the middle 
 of their floors, and for the escape of the smoke, 
 leave only a small opening in the roof, often 
 not directly over the fire. In Italy and Spain 
 almost the only fires seen in sitting-rooms are 
 large dishes of live charcoal, or braziers, placed 
 in the middle, with the inmates sitting around, 
 and having to breathe the noxious carbonic acid 
 gas which ascends from the fire and mixes 
 with the air of the room. There is no chim- 
 ney ; and for the ventilation of the room, the 
 only provision is the windows and doors. A 
 o
 
 OX WARMING. 21 
 
 closed room with such a fire is, in continental 
 countries, a common means of suicide. The dif- 
 ference between the air from a charcoal fire, and 
 the smoke from a fire of coal or wood is, that in 
 the latter there are added to the chief ingredient, 
 or carbonic acid, others which strongly affect the 
 eyes and nose, and so force attention. Within a 
 few years the barbarous mode of warming here 
 described was, and I believe still is, used in the 
 halls of some of the London Inns of Court, and of 
 colleges at the old English Universities. 
 
 The openjire under a chimney. 
 
 16, The third step of advance in the use of fuel 
 probably was to construct over the fire, a flue, or 
 chimney, which should receive all the smoke or 
 offensive aeriform matters rising from fire, and by 
 forming of this a long light column of air, should 
 cause it to rise with what is called a strong 
 draught, and so depart to mix above with the 
 passing wind. This is the plan now generally used 
 in England, and we shall therefore take the com- 
 mon open English fire as a familiar standard with 
 which to compare other plans; and we shall 
 moreover consider all the plans in reference to 
 the great object sought by them, of obtaining 
 everywhere on earth, at will, the temperature 
 most congenial to the human constitution, such 
 as exists in an English summer evening, and in air 
 as pure as blows on any hill-top. 
 
 17. By an open English fire it is possible to obtain 
 in a room any temperature. The heat used is that 
 portion only which radiates around with the light,
 
 22 ON WARMING. 
 
 while all that is in the smoke passes up the 
 chimney. This radiated heat first warms the 
 walls and other objects on which it falls, and 
 these by contact with the air of the room then 
 warm it. There are however serious disadvan- 
 tages which we shall now enumerate. 
 
 18. I. Waste of fuel. We. find that of the 
 whole heat produced from the fuel used, about 
 seven-eighths ascend the chimney, and are abso- 
 lutely wasted. The loss of heat is, first, the more 
 than half which is in the smoke as it issues from the 
 burning mass. Secondly, that carried off by the 
 current of the warmed air of the room, which is 
 constantly entering the chimney between the fire 
 and the mantel-piece, and mixing with the smoke. 
 This is estimated at nearly two-eighths. Thirdly, 
 it is a fact that the black or visible part of the smoke 
 of a common fire is really a precious part of the 
 coal or wood escaping unburned. If then more 
 than half of the heat produced be in the smoke, 
 and nearly a fourth of it in the warm air from the 
 room which escapes with the smoke, and if about 
 an eighth of the combustible pass away unburned, 
 there is a loss of at least seven- eighths of the whole. 
 Count Rumford estimated the loss at still more ; 
 namely, fourteen-fifteenths. 
 
 19. II. Unequal heating at different distances from 
 the fire. This forms a remarkable contrast with the 
 uniform temperature in the air of a summer after- 
 noon. In rooms with a strong fire, in very cold 
 weather, it is not uncommon for persons to be 
 scorched on one side, and chilly or half frozen on 
 the other. This is true particularly of large
 
 ON WARMING. 23 
 
 apartments ; for as the intensity of radiating heat> 
 like radiating light, is only one-fourth as great 
 at a double distance, and so on, being inversely as 
 the square of the distance, distant walls are little 
 warmed, and therefore reflect little heat to the 
 backs of persons around the fire. In apartments 
 with open fire, there is ordinarily one circular line 
 around the fire in which persons must sit to be 
 comfortable ; within which line they are too hot, 
 and beyond which they are too cold. 
 
 20. III. Cold draughts. Air being constantly 
 wanted to feed the fire, and to supply the chimney 
 draught above described, the fresh air, entering by 
 doors and windows, is felt often most injuriously, 
 as cold currents. Such currents become very re- 
 markable when doors or windows are opened, for 
 the chimney can take much more than it receives 
 when the doors and windows are shut. Then for 
 the time the room with its chimney is like an open 
 funnel, rapidly discharging its valuable contents. 
 
 21. IV. Cold Foot-bath. The fresh air which 
 enters in any case to supply the fire, being colder 
 and specifically heavier than the general mass 
 already in the room, lies at the bottom of this as a 
 distinct layer or stratum, demonstrable by thermo- 
 meters, and forming a dangerous cold bath for the 
 feet of the inmates, often compelling delicate per- 
 sons to keep their feet raised out of it by foot-stools, 
 or to use unusual covering to protect them. 
 
 22. V. Bad Ventilation. Notwithstanding the 
 rapid change of air in the room, perfect ventilation 
 is not effected. The breath of inmates does not 
 tend towards the chimney, but directly to the
 
 24 ON WARMING. 
 
 ceiling, and as it must therefore again , descend to 
 come below the level of the mantel-piece ere it 
 reach the chimney, the same air may be breathed 
 again and again. In a crowded room, with an 
 open fire, the air is for this reason often highly 
 impure. As another source of impure air in a 
 house, it is to be noticed, that the demand of the 
 chimneys, if not fully supplied by pure air from 
 about the windows and doors, operates through 
 any other apertures, and thus often brings in foul 
 air from drains, &c. 
 
 23. VI. Smoke and Dust are often unavoidable 
 from an open chimney, much affecting the comfort 
 and health of the inhabitants of the house, and 
 destroying the furniture. Householders would 
 make great sacrifices to be free from the annoy- 
 ance of smoke. In large mansions, with many 
 fires lighted, if the doors and windows fit closely, 
 and sufficiency of air for so many chimneys can- 
 not therefore enter by them, not only do the 
 unused chimneys become entrances for air, but 
 often the longest and most heated of the chimnies 
 in use, overpower the shorter and less heated, in 
 which also there are fires in the same way as the 
 long leg of a syphon overpowers the shorter leg, 
 and cause the shorter chimneys to discharge their 
 smoke into the rooms. 
 
 24. VII. Loss of Time. During the time every 
 morning while the fires are being lighted, the rooms 
 cannot be used; and there are, besides, the annoy- 
 ances of smells, smoke, dust, and noise. When 
 neglect of servants lets the fire go out in the 
 course of the day, it has to be lighted again.
 
 OX WARMING. 25 
 
 25. VIII. Danger to Property. In London 
 alone, there are at an average 140 fires per month. 
 
 26. IX. Danger to Person. Often in houses 
 burned, some of the inmates perish. The newspa- 
 pers of one day will sometimes report three or four 
 cases of children burned to death, by being left 
 with access to fires or candles. It is a frequent 
 accident for a lady, happening to stand or pass 
 near the fire when the door is opened, to have her 
 thin dress wafted towards the fire by the sudden 
 draught from the door, and so set in a blaze. 
 
 27. X. Expense of Attendance. To light the 
 fire in the morning, and to keep it alight with 
 tolerable uniformity during the day, the frequent 
 attendance and labour of a servant is required 
 much increasing the expense of the fire. 
 
 28. XI. Necessity of sweeping -boys. The suf- 
 ferings of these wretched children give great pain- 
 to many humane spirits. 
 
 29. The chief disadvantages of the open fire are 
 thus particularly distinguished and numbered, that 
 they may be readily referred to in subsequent 
 parts of the essay, where it will be shown that by 
 other means they are all avoidable. Count Rum- 
 ford suggested one modification of the open fire- 
 place, which considerably lessens some of them. 
 He called it the register- stove. It consists in 
 narrowing the entrance or throat of the chimney 
 by a plate, which can be moved to vary the size 
 of the aperture. By this means, particularly if 
 the opening be near the fire, the very hot air 
 directly from the fire enters, before it can mix 
 with much colder air from the room, and thus
 
 26 ON WARMING. 
 
 the draught is increased so as to lessen the chance 
 of smoking (Defect No. VI.), the chance of cold 
 draughts (No. III.), and to diminish the waste of 
 the warm air of the room (No. I.) 
 
 The common close Stove. 
 
 30. In Russia, and in northern continental 
 Europe generally, where fuel is not so abundant 
 and cheap as in England, but where the winter 
 cold is more severe, the open fire above described 
 would be much too expensive ; and, in fact, from 
 wasting so much of the heat, could not be made 
 at all to answer the purpose intended. Hence 
 another plan has been adopted, called the close 
 stove. 
 
 31. In the form here exhibited, 
 for instance, which is commonly 
 known as the Dutch stove, the 
 fuel rests on the bars of a grate 
 near the bottom, the air enters 
 below the grate to feed the com- 
 bustion ; fuel is introduced by a 
 door above the grate, which door 
 is closed while the stove is in action, and as it is 
 the only opening above the fire, no air can reach 
 the chimney, but what has fed the combustion. 
 Now this stove saves the waste of warm air, which, 
 in open fires, passes between the fire and the 
 mantel-piece, while by the surface of its body and 
 flue receiving not only the direct heat of the com- 
 bustion, but also of the intensely heated air rising 
 from the fire, it gives out to the room much of the 
 heat, which, in a common open fire, would at once
 
 ON WARMING. 27 
 
 ascend the chimney. Indeed, if the flue of the 
 stove be made sufficiently long, so as to expose 
 in the room a great surface for giving out heat, 
 nearly the whole heat of the combustion may be 
 applied to use. Then, in a room so heated, there 
 are neither draughts, smoke, nor dust. By such 
 a stove, therefore, several of the disadvantages of 
 the open fire are completely obviated. There is, 
 however, one disadvantage peculiar to the close 
 stove, which countervails nearly all its good qua- 
 lities, namely, that its very heated surface of iron 
 acts upon the air which comes in contact with it, 
 so as to impair exceedingly the air's purity and 
 fitness for respiration. The air acquires a burnt 
 and often sulphurous smell, in part, no doubt, 
 because dust, which it often carries, is burned, 
 and in part because there is a peculiar action of 
 the iron upon the air. It becomes very dry, too, 
 like that of an African simoom, shrivelling every 
 thing which it touches ; and it acquires probably 
 some new electrical properties. These changes 
 combined, make it so offensive, that Englishmen 
 unaccustomed to it, cannot bear it. In this country 
 many forms have been proposed, some of them 
 gracefully designed, with transparent talc doors 
 and other attractions ; and they have been tried 
 in rooms, public offices, passages, halls, &c., but 
 have been afterwards very generally abandoned. 
 Persons breathing the air heated by them are often 
 affected by headachs, giddiness, stupor, loss of 
 appetite, ophthalmia, &c. A north-east wind, 
 which distresses many people, bringing asthmas, 
 croups, &c., and which withers vegetation, is
 
 28 ON WARMING. 
 
 peculiar chiefly in being dry. The stove above 
 described is much used in this country by laun- 
 dresses and others for drying, and in that use it 
 is good and economical. A very common fire-place 
 in the United States of North America, is a square 
 close iron stove, such as 
 here shown, with a ves- 
 o sel of water upon it to 
 
 ** A - give moisture to the air. 
 The stove has a hearth- 
 plate projecting under 
 the door D ; the wood 
 fuel is burned within at 
 A, and the flame passes 
 
 along by B, to the 
 chimney C, around an 
 inner box, which is the cooking oven of the 
 family, opening by a door in the side of the stove. 
 The fuel is introduced by a large door at D, 
 in which there is a smaller door, which, as well 
 as the larger is usually kept shut, because 
 enough air can enter by the joinings around, but 
 in cold weather the small door is opened, to in- 
 crease the combustion. The stove has iron legs, of 
 about a foot long. 
 
 32. In northern continental Europe, to avoid 
 deteriorating the air by the overheating of the 
 surface of an iron stove, it is now common 
 to make close stoves and their chimneys of thick 
 brick-work, either included in the walls, or pro- 
 jecting as a bulky mass into the rooms, the mass 
 being, often covered with porcelain. These do 
 not allow the heat of the fire to pass outwards so
 
 ON WARMING. 29 
 
 quickly as a metal stove, and hence their exterior 
 does not become so much heated. In many cases, 
 to prevent as much as possible any waste of the 
 warm air from the room, the stove is not fed with 
 air from the room itself, but from a passage near, 
 or from the external air. Such massive stoves 
 are charged with fuel, and lighted, in general, 
 only once in the day ; and after the combustion 
 has continued long enough to drive off all the 
 evaporable matter from the fuel of wood or coal, 
 the chimney is nearly closed, and the remaining 
 ignited charcoal or coke is allowed slowly to 
 consume. The heated stove continues to warm 
 the room long after the fire is extinguished, but 
 of course with diminishing power. These stoves, 
 as compared with an open fire, are very econo- 
 mical. An English gentleman once at St. Peters- 
 burg, wishing to see there his old English fire, 
 had an open chimney constructed, but found that 
 with all it could do, and although the close stove 
 also was plied as much as possible, and was lighted 
 twice in the day instead of once, the room was 
 much colder than before. 
 
 33. An economical mode, known in China, of 
 using fuel to warm rooms, is to have the floors of 
 tile, below which the hot smoke of a close fire 
 passes. 
 
 34. In England, where such activity of thought 
 prevails on all subjects interesting to .humanity, 
 and where, from the advancement of the arts 
 generally, wants in relation to temperature arose, 
 which scarcely existed elsewhere as in the
 
 30 ON WARMING. 
 
 necessity of heating factory rooms so large, that 
 one fire was insufficient, and more than one were 
 inadmissible, the imperfection of the open fire, 
 and of the close stoves, having been strongly felt, 
 other means were eagerly sought, and are now 
 extensively used ; namely, 1 . Steam admitted to 
 pipes or other vessels placed in the apartments 
 to be warmed ; 2. Hot water similarly admitted 
 and distributed and circulating back to the boiler 
 to be heated again ; and, 3. Heated air prepared 
 in a separate place, and then distributed by 
 various means over the building to be warmed. 
 
 Of Heating by Steam. 
 
 35. I. Steam admitted into any vessel not so 
 hot as itself, is rapidly condensed into water, and 
 at the same time gives its heat to the vessel which 
 may then diffuse the heat in the space around. It 
 is found that if a boiler for heating a house by 
 steam be carefully set, like that of a steam-engine, 
 on a close furnace or fire-place, which admits no 
 more airthan is required to support the combustion, 
 and keeps the hot air in contact with the sides of the ( 
 boiler, until as much as may be of the heat is taken 
 from it, by such a boiler nearly a half of all the 
 heat produced in the combustion is applied to 
 use, instead of the one-eighth of an open fire. 
 There is a saving, therefore, of three-eighths in 
 the fuel used, as compared with open fires. The 
 other advantages are, the power of distributing 
 the heat as may be desired, there being no dust 
 or smoke in the room, no draughts, no cold air on 
 the floor, no danger of fire in the place warmed,
 
 OX WARMING. 31 
 
 and that when there are many rooms or a large 
 establishment to be warmed from one boiler, 
 less attendance of servants is needed. This mode 
 of heating is found highly advantageous in our 
 extensive manufactories, where steam-engines and 
 boilers are already established for other purposes. 
 In our cotton factories, accordingly, where the 
 quality of the thread preparing is injured by even 
 a small change of temperature, steam is universally 
 used, and where a good system of ventilation is 
 added, the air of the establishment is at all 
 times almost as temperate and pure as can be 
 desired, and the best effects have been produced 
 on the health of the work-people. 
 
 3G. The objections to steam heating for smaller 
 establishments are the great expense of construct- 
 ing and placing the apparatus ; consisting of 
 boiler, fire-place, safety-valves, feeding-pipes, 
 distributing-pipes, &c. &c. ; then the danger of 
 explosion ; the chance of the apparatus falling out 
 of order, and the difficulty of getting servants to 
 manage it well and safely ; the time to wait after 
 lighting the fire before the apparatus acts; and 
 that it cannot be used at a lower temperature 
 than 212, for the steam ceases to enter it when 
 the water ceases to boil ; and even if the boiling 
 be not sufficiently active, the distant parts of the 
 pipes will receive no steam, and will become 
 quite cold. 
 
 37. To determine the extent of surface of steam- 
 pipe or vessel necessary to warm particular apart- 
 ments, it was to be considered that the loss of heat 
 from them occurs in three ways: 1st, rapidly
 
 32 ON WARMING. 
 
 through the thin glass of the windows; 2dly, more 
 slowly through the thick substance of the walls, 
 floor, and ceiling ; and, 3dly, in combination with 
 the air which escapes at the joinings of the win- 
 dows and doors, or at other openings purposely 
 made for ventilation. Different writers and manu- 
 facturers have made very different estimates of 
 the quantities of heat lost in these various ways, 
 and as yet no exposition of the matters has been 
 made with the accuracy which the subject deserves; 
 but an intermediate estimate, as applied to com- 
 mon cases, may be shortly stated thus : that in a 
 winter day, with the external temperature at 10 
 below freezing, to maintain in an ordinary apart- 
 ment the agreeable and healthful temperature of 
 60, there must be of surface of steam-pipe, or 
 other steam-vessel, heated to 200, (which is the 
 average surface-temperature of vessels filled with 
 steam of 212,) about one foot square for every six 
 feet of single glass window, of usual thickness ; as 
 much for every 120 feet of wall, roof and ceiling, 
 of ordinary material and thickness ; and as much 
 for every six cubic feet of hot air escaping per 
 minute as ventilation, and replaced by cold air. A 
 window, with the usual accuracy of fitting, is held 
 to allow about eight feet of air to pass by it in a 
 minute, and there should be for ventilation at 
 least three feet of air a minute for each person 
 in the room. According to this view, the quantity 
 of steam-pipe or vessel needed, under the tempe- 
 ratures supposed, for a room sixteen feet square 
 by twelve feet high, with two windows, each seven 
 feet by three, and with ventilation by them or
 
 OX WARMING. 33 
 
 otherwise at the rate of sixteen cubic feet per 
 minute, would be 
 
 For 42 Square feet of glass (requiring 1 foot for 6) ... 7 
 
 1,238 Feet of wall, floor. 1 , . . , ,, ,. IO A\ im 
 and ceiling .' j (requmng 1 foot for 120) ...10 
 
 16 Feet per minute, "I , . . -, c . c c\ 02 
 ventilation j ( re q u 'S l foot for 6 > 2 
 
 Total of heating surface required 20 
 
 which is, twenty feet of pipe four inches in dia- 
 meter, or any other vessel having the same extent 
 of surface, as a box two feet high, with square 
 top and bottom of about 18 inches. It may be 
 noticed that nearly the same quantity of heated 
 surface would suffice for a larger room, provided 
 the quantity of window-glass and of the ventilation 
 were not greater ; for the extent of wall owing to 
 its slow conducting quality produces compara- 
 tively little effect. 
 
 38. An elaborate exposition of the laws of trans- 
 ference of heat is contained in Leslie's Essay, in 
 Tredgold's able Treatise on Warming, written when 
 steam was deemed the generally preferable means 
 of effecting the object, and in various reports of 
 accurate courses of experiment on the subjects. 
 To these the reader is referred for fuller informa- 
 tion ; but to give an idea of the mode of dealing 
 with the subject, the following short explanation 
 is added. 
 
 39. A heated surface, as of iron, glass, &c. at 
 temperatures likely to be met with in rooms, if 
 exposed to colder air, gives out heat with rapidity 
 nearly proportioned to the excess of its temperature 
 above that of the air around it, less than half the
 
 34 ON WARMING. 
 
 heat being given out by radiation, and more than 
 half by the contact of the air. Thus one foot of 
 iron pipe of 200 external temperature in the air 
 of a room at 60, the difference between them or 
 excess being therefore 140, gives out nearly 
 seven times as much heat in a minute as when its 
 temperature falls to 80, reducing the excess to 
 20, or a seventh of what it was. If window-glass, 
 therefore, cooled at the same rate as iron plate, 
 one foot of the steam-pipe iron would give out as 
 much heat as would be dissipated from the room 
 into the external air by about five feet of window, 
 the outer surface of which were 30 warmer than 
 that air. But, because glass both conducts and 
 radiates heat in any case about one-seventh slower 
 than iron, the external surface of glass of ordinary 
 thickness, forming the window of a room heated 
 to 60, would in an atmosphere of 22, be under 
 50, leaving therefore an excess of less than 30; 
 and about six feet of glass would be required to 
 dissipate the heat given out by one foot of the 
 iron steam-pipe. Through double windows, whe- 
 ther consisting of two sashes, or of double panes 
 half an inch apart in the same sash, the loss of 
 heat is only about a fourth part of what takes 
 place through a single window. Then, it is a fact 
 ascertained by experiment, that one foot of black 
 or brown iron surface, the iron being of moderate 
 thickness, with 140 excess of temperature cools 
 in one second of time 156 cubic inches of water, 
 one degree Fahrenheit's thermometer. From this 
 standard fact, and the law given above, a rough 
 calculation may be made for any other combina-
 
 OX WARMIXG. 35 
 
 tion of time, surface, excess, and quantity. And 
 it is to be recollected that the quantity of heat 
 which changes in any degree the temperature of a 
 cubic foot of water, produces the same change on 
 2,850 cubic feet of atmospheric air. 
 
 Warming by Hot Water. 
 
 40. Of this process there are two very distinct 
 forms or modifications, dependent on the tempera- 
 tures of the water. In the first, water is used at or 
 below the ordinary boiling temperature, and where 
 the pipes do not rise much above the level of the 
 boiler, the vessels need be of no unusual strength. 
 In the second, the water is heated often to beyond 
 300, and is seeking, therefore, to burst out as 
 steam, with force of seventy pounds or more on 
 the square inch, and can be confined only by 
 very strong, or high-pressure apparatus. 
 
 41. For the first modification is required an ordi- 
 nary boiler ; from near the top of which a tube rises 
 to traverse the place or places to be warmed, and 
 then returns to terminate near the bottom of the 
 boiler. Along this tube the heated water circulates, 
 giving out its heat as it proceeds. If the boiler 
 be open to the air, the tube, when once filled with 
 water, acts as a syphon, having an ascending cur- 
 rent of hot water in the shorter leg, and a des- 
 cending current of the cooled water in the longer ; 
 the rapidity of motion depending on the diffe- 
 rence in the lengths of column, and in the tem- 
 peratures, or specific gravities of the two currents. 
 If the boiler be closed, except through the tubes, 
 the syphon action disappears, and the boiler with 
 
 D 2
 
 36 OX WARMING. 
 
 the tubes become as one vessel ; but still the 
 circulation proceeds as in the other case. 
 
 42. This mode of heating, in many respects, re- 
 sembles that by steam, but there are differences. 
 Advantages are, that for some situations it costs 
 less ; that with the open boiler there is no danger 
 of explosion ; that whereas steam does not rise 
 into ordinary pipes until the water producing it 
 has attained the boiling temperature, in this, 
 the circulating water may be of any temperature 
 above that of surrounding objects, and will have 
 motion beginning as soon as the fire is lighted, and 
 not ceasing until the water becomes again quite 
 cold, that the great mass of water heated, lessens 
 the chance of fluctuations of temperature in the 
 place. On these accounts hot water, as a heat- 
 distributor, has lately been preferred to steam in 
 many hot-houses, conservatories, private-dwellings, 
 schools, public offices, &c. Disadvantages of the 
 water-circulation at low temperature are, the great 
 bulk of the apparatus, the slowness of the motion 
 where the height of columns is small, the chance,, 
 if the fire be not lighted, of the water freezing, 
 and bursting the pipes, and the long time required 
 to heat or cool the mass of water employed. Only 
 half of the heat of the combustion is applied to use,, 
 by any mode of heating water. 
 
 43. The other, or high-pressure form of hot-water 
 apparatus proposed by Mr. Perkins, consists in a 
 great length (it may be 1,000 feet or more) of very 
 strong iron pipe, of from one to two inches in 
 diameter, formed into a circuit, in which the water 
 endlessly runs round. Such tube, from its small-
 
 ON WARMING. 37 
 
 ness and flexibility, is easily laid along to fit any 
 form and succession of rooms and passages, and is 
 gathered into a heap by being coiled up like a 
 screw in the various situations where much sur- 
 face is required, whether for giving out heat, as 
 in rooms and stair-cases ; or for receiving it, as 
 around the burning fuel. It thus requires neither 
 radiating vessel nor boiler, other than portions of 
 itself, and is therefore beautifully simple ; but 
 from the great strength and thickness required in 
 the whole length of the pipe, with safety-valves, 
 feeding-contrivance, peculiar joinings, &c. of cor- 
 responding strength, it becomes an expensive 
 apparatus. It is liable to bursting, although the 
 accident is not of great importance ; and its high 
 temperature often gives smell, or other disagree- 
 able quality to the air. The circulation in it is 
 very rapid, owing to the water, on leaving the fire- 
 place, being generally mixed with steam, and 
 therefore being as a mass, specifically light. 
 
 44. By using, with the forms of steam and hot- 
 water apparatus now described, the self-regulating 
 fire treated of in a future part of this essay, several 
 of the objections to such apparatus would be 
 avoided. 
 
 Hot- Air Distribution. 
 
 45. For this plan of warming, the air has 
 hitherto been usually prepared by sending it 
 through pipes or other spaces connected with fur- 
 naces, fire-grates, stoves and their flues, cockles, 
 &c. and more lately by making it pass around 
 or between thin boxes or pipes filled with hot
 
 38 OX WARMING. 
 
 water. When thus heated, it has been directed, 
 either unmixed or diluted according to its tem- 
 perature, into the apartments. By all these pro- 
 cesses, except the last- mentioned, the air is gene- 
 rally much vitiated from being over- heated, as 
 described at Art. 31, under the head of the 
 " Close Stove." It was air driven against the 
 surface of iron plates, or vessels, nearly red hot, 
 and then diluted with colder air before being 
 admitted to the apartment, which, in the winter 
 of 1805-6, affected the health of the 200 persons 
 occupying the Long Room in the Custom-House 
 so seriously as to draw public attention to the 
 subject. In any case of sending very heated air 
 into an apartment, (unless, contrary to common 
 practice, it be admitted by many openings,) it 
 does not mix readily with the air already there, 
 but rises at once as a distinct mass or current to 
 the ceiling, and is then, in great part lost, by pass- 
 ing away in the ventilation. When the common 
 attempt has been made to distribute air heated 
 in one place to various rooms, at different dis- 
 tances, and on different levels, by the mere influ- 
 ence of the comparative levity of the heated air, 
 there has generally been a signal failure, owing to 
 the disturbing influences of difference of altitude 
 in the conduit-pipes or columns, and of difference 
 in the action of the chimneys, windows, and doors 
 in the various rooms. The danger of sending cur- 
 rents of very hot air through parts of buildings in 
 which there is wood, is proved by almost daily 
 occurrences in this country. Recent remarkable 
 examples are the destruction of the Houses of
 
 ON WARMING. 39 
 
 Parliament in 1835 ; of part of the University 
 College, London, in 1836 ; and of the costly edi- 
 fice in Liverpool, called the Mechanics' Institute, 
 in the same year. It is possible, however, to 
 warm air moderately by a hot water, or steam 
 apparatus, or by other means which shall certainly 
 prevent the temperature from exceeding 212, and 
 then, by unfailing mechanical agency, to distribute 
 it as desired through any building. In a few in- 
 stances this has already been accomplished ; but 
 at so great an expense, that if the apparatus used 
 had not existed for other purposes, it would never 
 have been erected. There are much cheaper means 
 of accomplishing the object, as will be explained 
 below. 
 
 Self -Regulating Fire; or, Thermometer- Stove. 
 
 46. The preceding paragraphs contain a sketch 
 of the chief means of warming which were known 
 and practised, up to the year 1834. Various pro- 
 fessional occurrences at that time called my atten- 
 tion to the important art of controlling temperature 
 in our dwellings, for the purposes of health and 
 comfort. The subject had before engaged my 
 thoughts, enough to make me aware that there 
 were many errors of common practice easily avoid- 
 able, and to give me an impression that a revision of 
 it might lead to new and useful results. Setting 
 before me, therefore, the problem "to secure effec- 
 tually, in any part of the world, and at all seasons, 
 the temperature, moisture, and purity of atmo- 
 sphere most congenial to the human constitution,"
 
 40 ON WARMING. 
 
 I resumed my study. That T might have constant 
 motive and better opportunity to observe, to expe- 
 riment, and to reflect on the subject, I directed a 
 manufacturer to fit up in my library, the apparatus 
 for warming by circulating hot water. Accord- 
 ingly a box of iron to hold water was placed at 
 one side of the room, having communication by 
 ascending and descending pipes, with a boiler 
 fixed at the back of the kitchen fire, and so that 
 as soon as the fire was lighted, circulation of the 
 water might commence, and be continued at 
 nearly boiling heat while the fire burned. This 
 apparatus effected, in weather not very cold, (for 
 it was of too small dimensions for the room) all 
 the pleasing results described in a former page, as 
 belonging to the warm-water circulation mild, 
 equal temperature over the room, no dust, smoke, 
 .trouble of watching a fire, danger of fire, draughts, 
 cold layer of air on the floor, &c. The objec- 
 tions were, 1 st, That in very cold winter nights, 
 when the kitchen fire was not burning, the safety 
 and supply pipes which descended from an exter- 
 nal cistern, were exposed to freeze. On one occa- 
 sion the water in the safety-pipe did freeze, and, 
 by shutting in the steam, endangered my safety 
 when the fire was next lighted. 2dly, Considerable 
 expense of fuel. 3dly, Considerable original ex- 
 pense of apparatus. 4thly, That when once fixed 
 it could not be moved to another place. 5thly, The 
 noise and disturbance (likely to distress a sick per- 
 son,) of the regiment of bricklayers, plumbers, 
 smiths, and carpenters, who came under a master 
 and foreman to set it.
 
 ON WARMING. 
 
 4i 
 
 47. A mode of obviating several of the objections 
 without much countervail- 
 ing trouble, at once occur- 
 red to me, and was tried ; 
 namely, to have the box 
 of water heated, not by 
 communication with a dis- 
 tant fire, but by a small 
 fire within itself, as here 
 represented. This consti- 
 tuted a water-clad stove, 
 and as the steam of the 
 water, when heated to the 
 boiling point, passed by 
 an aperture provided, into the chimney, the exter- 
 nal surface of the box could never be hotter than 
 boil ing- water, and could no more, therefore, vitiate 
 the air of the room than the simple water-box did. 
 To prevent the water from boiling too rapidly, 
 and being wasted, the air, to feed the combustion, 
 was admitted only by a small aperture near the 
 door of a close ash-pit, in which aperture was placed 
 a throttle-valve, regulated by a peculiar thermome- 
 ter which will be described in a future page. The 
 aperture was closed by the thermometer when- 
 ever the temperature reached the boiling point, or 
 any other point that might be chosen, and was 
 opened again whenever the thermometer fell to 
 below the point chosen. This stove, besides its 
 uniform moderate temperature for it was a box 
 of boiling water which, although giving out heat, 
 never cooled had nearly all the economical advan- 
 tages of the close German or Dutch stove, for so
 
 42 OX WARMING. 
 
 much of the chimney-flue might be exposed in the 
 room as to apply usefully nearly all the heat of 
 the smoke. There was here, however, still an 
 apparatus, rather difficult to make, and expensive, 
 liable to be out of order, heavy, requiring con- 
 siderable attention from servants, &c. It may be 
 mentioned, however, that several forms of the 
 water-clad stove may still be useful. 
 
 48. After the step made, by the construction of 
 the stove just described, it was easy to make ano- 
 ther and more important step. The object sought 
 was now clearly seen to be, merely to place in 
 any apartment the required extent of metallic 
 surface, kept steadily at a temperature not exceed- 
 ing 200 of Fahrenheit. It 'evidently was of no 
 importance what hot fluid filled and warmed the 
 vessel whether water, steam, oil, or air, or whether 
 there were an included fire provided the tempe- 
 rature of the surface was maintained ; for the box 
 in any case would be quite close, permitting no 
 escape of its contents. If, therefore, in a box of 
 the required size, a fire could be placed so as to 
 warm the box with perfect uniformity all around, 
 while the fire itself were so controlled by a self- 
 acting regulator, that it should burn always 
 exactly as fast as was required to keep the box 
 steadily at any desired temperature, the object 
 sought would be attained, and there would be 
 many concomitant advantages of cheapness, sim- 
 plicity, &c. These words have sketched the Self- 
 regulating Fire, or Thermometer -Stove, of which the 
 form first tried is now to be described more parti- 
 cularly by aid of the wood-cut.
 
 OX WARMING, 
 
 43 
 
 49. The outline abdc 
 represents a box formed a 
 of sheet-iron, and divided 
 by the partition g h into 
 two chambers, commu- 
 nicating freely at the top 
 and bottom. The letter 
 e marks the fire-box or p 
 furnace, formed of iron, 
 lined with fire-brick, and 
 resting on a close ash-pit, 
 of which b marks the 
 door, and near which 
 door there is a valved opening, by which air enters, 
 to feed the fire when the door is shut ; i marks the 
 door of the stove, by which fuel is introduced 
 c is the chimney-flue. While the stove-door and 
 ash-pit door are open, a fire may be lighted, and 
 will burn in the fire-box just as in a common 
 grate, and the smoke will rise and pass away by 
 the chimney, mixed with much colder air, rushing 
 in by the stove-door; but if the stove-door and 
 ash-pit door be then closed, and only as much air 
 is admitted by the valved opening in the ash-pit 
 as will just feed the combustion, only a small 
 corresponding quantity of air can pass away by 
 the chimney, and the whole box will soon be full 
 of the hot air or smoke from the fire circulating in 
 it, and rendering it every where of as uniform 
 temperature as if it were full of hot water. This 
 circulation takes place, because the air in the 
 front chamber around the fire-box, and which 
 receives as a mixture the red-hot air issuing from
 
 44 ON WARMING. 
 
 the fire, is hotter, and therefore specifically lighter, 
 than the air in the posterior chamber, which 
 receives no direct heat, but is always losing heat 
 from its sides and back ; and thus, as long as the 
 fire is burning, there must be circulation. The 
 whole mass of air is, in fact, seen to revolve, as 
 marked by the arrows, with great rapidity; so 
 that a person looking towards the bottom of the 
 stove through the stove-door i, might suppose, if 
 smoking fuel had been used to make the motion 
 visible, that he was looking in at the top of a 
 great chimney. The quantity of new air rising 
 from within the fuel, and the like quantity escap- 
 ing by the flue c, are very small, compared with 
 the revolving mass. There remains to be noticed 
 only the thermometer regulator of the combustion. 
 Many forms presented themselves to my mind, as 
 described in the section on the manufacture of the 
 stove, any one of which will close the air-passage, 
 slackening or suspending the combustion at any 
 desired degree, and will open it again instantly, 
 when the temperature falls below that degree. 
 
 50. I had thus a simple box of iron, of cheap 
 and easy construction, answering all the purposes 
 of expensive steam or hot-water apparatus, burn- 
 ing its fuel as steadily and regularly as an argand 
 lamp burns its oil, or as an hour-glass lets its 
 sand run through, and allowing me, by merely 
 touching a screw on the thermometer, rapidly to 
 increase or diminish its heat, as by touching 
 another regulating screw we increase or diminish 
 the light of a lamp. 
 
 51. What chiefly surprises a stranger in this new
 
 ON AVARMIXG. 45 
 
 stove, is the very small quantity of air required 
 to support the combustion which warms a large 
 room ; the whole might enter by an opening of half 
 an inch diameter, and the quantity of air or smoke 
 which passes into the chimney is of course pro- 
 portionally small. These facts at once suggest 
 how small the consumption of fuel must be, as 
 that depends on the quantity of air entering, how 
 perfect the combustion of the fuel must be where 
 so little is expended, and how completely the 
 heat produced in the combustion must be turned 
 to account. The combustion is so perfect, because 
 the fuel is surrounded by thick fire-brick, which 
 confines the heat so as to maintain intense ignition ; 
 and the saving of heat is proved by the rapidly 
 diminishing temperature of the flue, detected by 
 a hand, passed along it from the stove. During the 
 winter 1836-7, which was very long and severe, 
 my library was warmed by the thermometer-stove 
 alone. The fire was never extinguished, except 
 for experiment or to allow the removal of pieces 
 of stone which had been in the coal, and this 
 might have been prevented by making the grate 
 with a moveable, or shifting bar. The temperature 
 was uniformly from 60 to 63. I might have made 
 it as much lower or higher as I liked. The quan- 
 tity of coal used (Welch stone coal) was, for several 
 of the colder months, six pounds a day less than 
 a pennyworth or at- the rate of half a ton in the 
 six winter months. This was a smaller expense 
 than of the wood needed to light an ordinary fire, 
 therefore the saving was equal to the whole amount 
 of the coal-merchant's ordinary bill. The grate, or
 
 46 ON WARMIXG. 
 
 fire-box, fully charged, held a supply for twenty- 
 six hours. It might have been made twice as large, 
 or to hold a supply for two days, and there would 
 have been no waste, as the consumption is only 
 proportioned to the air allowed to enter ; but, in 
 general, it may be convenient to have to look at 
 and charge the fire in the middle of the day and 
 at bed-time. Many strangers coming into my room 
 did not suspect that I had fire in the stove, for it 
 was used generally as a table for a book-stand. 
 They thought the agreeable warmth of the room 
 came from the kitchen, or some neighbouring 
 room. I believe that persons must themselves feel, 
 to be able truly to conceive, the charm, in dreary 
 winter, of knowing, wherever they be, in cold, or 
 rain, or snow, that a perfect and unvarying summer 
 room always awaits their return home. 
 
 52. The thermometer-stove, as compared with 
 other modes of warming, will be best understood, 
 by reviewing its chief qualities. A general ex- 
 pression for them is, that it possesses all the advan- 
 tages of steam or hot-water warming, with many 
 advantages peculiar to itself. 
 
 53. I. Economy of fuel. We have seen, at Art. 
 18, that a common open fire wastes seven-eighths 
 of the heat produced. This stove saves or puts to 
 use very nearly the whole, because, first, it does 
 not allow the air which has fed the combustion to 
 escape, until deprived of nearly all the heat ; and 
 secondly, it does not allow any of the warm air of 
 the room, except the little which feeds the fire, to 
 escape through the chimney. Marking, strikingly, 
 how the heat produced in the stove is applied
 
 OX WARMING. 47 
 
 to use, we find, that a sheet of paper set fire to, 
 and put into a cold stove, will warm the whole 
 almost as if boiling water had been poured into it, 
 and the heat i.s afterwards all diffused in the room. 
 The same sheet of paper burned under the chimney 
 of an ordinary grate, would produce no sensible 
 effect in the room. The ascertained fact respecting 
 the expenditure of the stove is, that an eighth of 
 the fuel which is needed for a common fire suffices ; 
 and stone-coal, or anthracite, coke, and even 
 cinders in a word, the cheapest fuel answers 
 better than that which is dearer. Thus, since 
 bituminous coal has become so precious, as the 
 gas-giving material for common lights, the rem- 
 nant of it, after the gas is taken away, has also 
 acquired a new value. 
 
 54. II. Uniform temperature in all parts of the 
 room, and throughout the day. There is no scorch- 
 ing on one side, and freezing on the other, as often 
 with a common fire. The occupants of a room are 
 not obliged in winter to abandon their sofas or 
 other conveniences, to crowd around the fire. 
 There can be no draughts in the room, nor layer 
 of cold air on the floor. Again, throughout the day, 
 invalids may have always around them, without 
 watching or anxiety, the steady temperature which 
 is so important to them. How unlike this to what 
 happens with the open fire, which in spite of close 
 and laborious attention, is fluctuating from hour to 
 hour. If an uniformity of temperature through the 
 night and day be required, greater than by reason 
 of fluctuating external temperature a steady action 
 of the stove can give, it is attainable by making a
 
 48 ON WARMING. 
 
 thermometer obedient to the temperature of the 
 room co-operate in regulating the stove with the 
 thermometer of the stove itself. 
 
 55. III. TheStove is always alight. This pecu- 
 liarity, next to the saving of fuel, if not even 
 before it, may be deemed a leading characteristic 
 or advantage of the stove, from which many minor 
 advantages flow. Its importance is perceived by 
 reflecting on the disadvantages of common inter- 
 rupted fires, as the trouble and expense, with 
 smoke, dust, and noise, of lighting the fire every 
 morning at least, and at all other times when from 
 carelessness or accident it has been allowed to go 
 out, rooms becoming useless for the time when 
 there is no fire, and valuable hours for labour 
 being thus often lost, the distress, and often great 
 injury to invalids from the fire becoming extin- 
 guished during the night, or the scarcely less 
 objectionable alternative of disturbed rest from 
 attendants entering to trim the fire, that a room 
 with a fire cannot be locked up and left for any 
 considerable time, without the probability of the 
 fire being extinguished, the great expense of 
 watching the fire in many chemical and other 
 processes, which require that an uniform heat be 
 continued for many hours or days ; and the farther 
 loss, because no watching is sufficient effectually 
 to secure these ends, the fact that in many 
 manufactories, the frost of one night, if not 
 resisted, will effect damage to great amounts, 
 the dependence of persons generally, in winter, 
 on the regularity of servants or others, by being 
 obliged, in the mornings, to wait in bed, until fires
 
 OX VARMIXG. 49 
 
 are lighted and rooms are put into order. The early 
 riser, student, or man of business, with his ever- 
 burning stove and alarum clock, is independent of 
 seasons. In England, many persons acquire the 
 habit of lying a-bed in winter, as above explained, 
 and then continue it in the summer, and become 
 eventually sluggards through life, from the acci- 
 dent of our imperfect domestic economy. It is 
 because the stove is ever alight, that the tempera- 
 ture of the place warmed by it is so uniform, and 
 that so much fuel is saved. More fuel would be 
 wasted in one morning hour, by the attempt sud- 
 denly to raise the temperature of a room which 
 had become cold in the night, than by keeping 
 the fire burning moderately all the night. 
 
 56. IV. No smoke can come from it, for the 
 only passage is the small opening by which air 
 enters to feed the fire, and in this, if desired, there 
 may be a flap or valve allowing air to enter freely, 
 but not to return. If the chimney be bad, or 
 from any cause will not draw, the stagnation or 
 downward pressure of the air in it may extinguish 
 the fire, but cannot return smoke through a well- 
 made stove. Neither will the presence of a stove 
 in a house disturb the draught of other chimneys, 
 causing them to smoke, nor will it draw foul air 
 from drains. As in the thermometer-stoves, fuel is 
 used which produces no visible smoke, we may 
 here remark, once for all, that when we speak of 
 the smoke of the stove, we mean the carbonic acid 
 or invisible gases which rise from it, as from a 
 charcoal fire, or gas flame, or wax candle. 
 
 57. V. No dust, such as arises from poking 
 E
 
 50 OX \VARMI\G. 
 
 common fires, and which is so hurtful to furniture, 
 books, and articles of female dress. When the fire 
 of the stove has to be stirred, and the ashes are 
 taken away, the dust set in motion in the close 
 ash-pit naturally passes through the fire and up 
 the chimney. 
 
 58. VI. No danger to persons, such as is exhi- 
 bited when a child or an epileptic person falls 
 against the bars of a common grate, or when a 
 lady's dress catches fire by too near an approach. 
 Hence its fitness for dressing-rooms and nurseries. 
 The fire of the stove is shut up in a box, and is 
 farther secured in the fire-pot, at a distance even 
 from the sides of the box, and never while the 
 regulator is acting will the box become hotter 
 than boiling water, or the particular degree fixed 
 on. If the chimney be of moderate size, the box 
 could not be made dangerously hot by any possible 
 mismanagement. And besides, a cage of wire- 
 work might surround it, as a guard to prevent 
 children or other persons from touching it. The 
 chimney of the stove cannot be set fire to, under 
 any ordinary circumstances; and if it were, the 
 fire, by shutting the doors and valve, could be 
 immediately extinguished. 
 
 59. VII. No danger to property , such as attaches 
 to common fires. No live coal can be shot from 
 this close fire, and any accident is scarcely con- 
 ceivable by which an object could be inflamed by 
 it. 
 
 60. VIII. Obedience to command. The screw 
 of the regulator as certainly increases or dimi- 
 nishes the temperature, as the screw of a lamp
 
 OX WARMING. 51 
 
 varies the light; and by having a thermometer 
 accurately made and graduated, the very degree 
 of heat required in any art as in enamel painting, 
 &c. can be obtained with certainty. To manage 
 tolerably an open coal fire is no easy art, as stran- 
 gers in England at first discover. The fire is often 
 the master of the attendant, not the attendant of 
 the fire. A child may manage the stove, without 
 failing. 
 
 61. IX. The trifling original expense, compared 
 with the cost of apparatus for warming by steam, 
 hot water, or distributed hot air and as com- 
 pared even with a good open grate and fire-irons. 
 The saving of fuel in one winter would nearly pay 
 for the stove. 
 
 62. X. The small expense of attendance upon it-, 
 whereas if a common fire is to be kept burning, 
 there must be some person to watch it, and if 
 there be several such fires, the servant will be 
 almost constantly employed passing from room to 
 room. 
 
 63. XI. It is easily moved, after the chimneys 
 are prepared, from room to room, or house to house 
 nearly as a large chair, or a chest of drawers 
 may be moved. 
 
 64. XII. Graceful form. It maybe fashioned 
 to please the fancy as a pedestal, vase, urn, pillar, 
 even a statue, or, indeed, may be of almost any 
 beautiful form. 
 
 65. XIII. It is a good cooking-stove, and there- 
 fore the poor man's stove. A second small iron 
 box placed within it, with a door opening out- 
 wards through the side of the stove, is a perfect 
 E 2
 
 52 ON WARMIXG. 
 
 oven as is proved, indeed, by the common 
 American stove, described at Art. 31, which in this 
 respect resembles it. A small kettle or cooking 
 vessel may be placed directly on the fire. Pota- 
 toes and other things may be roasted in the ash-pit; 
 and if the ash-pit be made large, with the fire-bars 
 sloping, so as to present a considerable surface of 
 naked fire looking downward and forward, meat 
 may be roasted there. The top of the stove is a 
 perfect hot-plate, on which any thing may stand, 
 either to be heated, or to be kept warm. If the 
 stove be heated to the boiling point of water, a 
 tea-pot of cold water placed upon it, under a dish 
 cover, soon contains boiling water, and similarly 
 eggs or other things may be boiled. Thus the 
 breakfast of a solitary student in London chambers 
 may be easily prepared by himself. 
 
 66. XIV. No sweeping -boys are required, as 
 already explained. 
 
 67. The advantages hitherto enumerated of the 
 stove in its domestic bearing, might be otherwise 
 classified under the heads of Economy of Fuel 
 Economy of Original Expense Economy of Ser- 
 vice Economy of Comfort Economy of Health 
 and of Life Economy of Furniture and Property 
 generally and Economy of Time. 
 
 68. There is one circumstance connected with 
 this stove, as used in a sitting-room, which may at 
 first by some be deemed a disadvantage, namely, 
 that the fire is concealed from view. But that the 
 English feeling on this subject is merely an acci- 
 dent, is proved by the contrary feeling existing as 
 strongly elsewhere, as in Northern European and
 
 ON WARMING. 53 
 
 some American countries. While the Englishman 
 dreads losing his cheerful hearth or fireside, be- 
 cause of his pleasing associations with it, people 
 on the Continent dread having such a fire, because 
 their experience tells them that the open fire is 
 accompanied by cold draughts, discomfort, and 
 danger, which do not attend the close stove : and 
 if the Englishman himself would, in summer, fly 
 from a fire as an insufferable object, he may soon, 
 in winter, when the thermometer- stove makes a 
 summer for him, cease to desire it. It is possible, 
 however, to have an open fire, with many of the 
 qualities of the stove, as will be shewn in a future 
 paragraph. 
 
 9. Another objection likely to be made by 
 persons before reflection, is, that they would be 
 rendered very susceptible of cold by living in 
 rooms always heated to about 60. Now the tem- 
 perature of 60 is in most countries the medium 
 equally distant from the extremes of heat and cold, 
 which persons may permanently use, or may ap- 
 proach or leave, with perfect safety. The danger of 
 catching colds or heats is on entering or leaving 
 rooms with open fires, heated as they often are 
 to 70 and more, or cooled to 50 and below. 
 
 70. Besides the uses of the stove in dwelling- 
 houses, which in the preceding paragraphs have 
 been chiefly contemplated, there are likely to be 
 many applications of it in the arts of life, as 1st, 
 By chemists in distillation, preparing infusions 
 and vegetable extracts, &c. 2d, By cooks in num- 
 berless cases ; 3d, In the arts of tempering steel, 
 enamelling, painting on glass or porcelain. 4th,
 
 54 OX WARMING. 
 
 For cellars which have no chimneys ; for arches 
 under raised roads to make them habitable ; for 
 low, damp apartments, for strong rooms, in which 
 plate, deeds, books, &c. are secured. 5th, In the 
 arts of drying, as for printers ; in feather-dressing, 
 washing, drying vegetable substances. 6th, In 
 warehouses or stores ; in rooms of painters, sculp- 
 tors, &c. 7th, In stables occasionally and dog- 
 kennels, houses for wild animals, &c. 
 
 7f. Were this thermometer- stove to be adopted 
 generally in England, consequences of no ordinary 
 importance would follow, adding to the list of 
 advantages, above given, others of a more general 
 nature ; as, 1st, the great saving of coal. This 
 substance, unlike corn, of which every season 
 brings a new supply, exists in any country in a 
 limited quantity tending to exhaustion ; and in 
 England, owing to the recent prodigiously multi- 
 plied uses of it in our manufactures and arts, 
 rendering the state of society in England more 
 and more dependent upon the coal mines, the 
 price has risen considerably. A new means which 
 should lessen the consumption of coal only one- 
 half, would be equivalent to the discovery of as 
 many more coal-beds in the country as at present 
 exist in it. 2d. In London the atmosphere would 
 have as much less carbonic acid in it as less coal 
 were used, and nearly all visible smoke would 
 cease, for the stove makes none. At present, over 
 London, at any instant is to be seen floating in 
 the atmosphere as smoke, many chaldrons of the 
 most precious part of our coal, that part, in fact, 
 which, with proper management, is convertible
 
 OX WARMING. 55 
 
 into gas for lights. Authors have calculated that 
 one-eighth of all the coal brought to London 
 escapes in this way which at present must be a 
 loss of 100,000 chaldrons a year. 3d. There might 
 be great increase of domestic comfort among the 
 poorer classes, to whom want of warmth is one 
 of the greatest miseries, often driving them to the 
 destructive alternative of dram-drinking; or at 
 least, to frequenting heated public-houses, be- 
 cause there is not warmth at home. 4th. If good 
 ventilation were superadded, a great proportion of 
 the winter diseases of the people, both rich and 
 poor, might disappear. During the prevalence of 
 influenza in late years, houses warmed uniformly 
 by steam or hot-water, have been found to give 
 almost perfect security to their inhabitants. The 
 fact has been striking in some extensive establish- 
 ments, as in the Hanwell Asylum for Lunatics. 
 
 72. The preceding remarks apply to the thermo- 
 meter-stove, chiefly in relation to English wants, 
 but it is equally fitted for the use of other coun- 
 tries, as of continental Europe and America. In 
 Italy, Spain, and North Africa, almost the only 
 means of winter-warming is the open chafing- 
 dish or brazier filled with burning charcoal. This 
 rapidly contaminates the air. In rooms having no 
 chimneys, like most rooms in Southern Europe, a 
 chimney-tube or flue from the stove passed out to 
 leeward at a window, or a hole in the wall would 
 suffice : if the chimney opened to windward, it 
 would have to be accompanied by an air tube to 
 feed the stove, of which the mouth received the 
 same atmospheric pressure as the chimney.
 
 56 
 
 ON WARMFNG. 
 
 73. The stove is well adapted, also, for ships; 
 and one of small size, burning charcoal, might 
 serve well to warm carnages, in winter journeys. 
 A useful application of it would be to warm water 
 in baths. A small box, water-tight of tinned iron 
 soldered, for example plunged into the water, with 
 an opening at the top, c, for 
 
 the admission of burning fuel 
 into the fire-pot, b, and one 
 tube, a, to carry pure air a 
 down to the ash-pit, while 
 another, d, served as a chim- 
 ney, would effect the purpose 
 readily. In this or the pre- 
 ceding modifications, the air- 
 feeding and chimney tubes might be placed toge- 
 ther, or at least near, and the apparatus might be 
 suspended with the appearance of a lamp. 
 
 74. After the next section, which describes 
 various means of ventilating, we shall show that 
 the thermometer-stove, in combination with these 
 means, and having a vessel of water on it, to diffuse 
 moisture, may be effectually applied to maintain a 
 healthful state of atmosphere, not only in private 
 dwellings, but also in hospitals, churches, thea- 
 tres, courts-of-lavv, schools, lecture-rooms, hot- 
 houses, &c. 
 
 ON VENTILATION. 
 
 ( The subject continued from Art. 10.) 
 
 75. Having now considered the modes of using 
 fuel to warm artificially, we resume, as promised,
 
 OX VENTILATION. 57 
 
 the consideration of modes of ventilating, often in- 
 timately connected with the process for warming. 
 7G. The nature of man's breathing, and the con- 
 version by it of the pure air, which is life to him, 
 into foul air, which is poison, have already been 
 explained at Art. 10, as also the beautiful provi- 
 sions of nature for ensuring the required supply 
 of air; first, by the heating, and consequent 
 rising into the atmosphere above, of air which has 
 been breathed, to be replaced by fresh air from 
 below; and, secondly, by the never-ceasing 
 greater motions, called winds, of the atmosphere 
 itself, which mingle the whole, and submit it 
 to influences maintaining its general purity. These 
 aerial movements are, to man, what the con- 
 stant gliding past of a clear river stream is to 
 the fishes which inhabit it ; and as certainly as we 
 should destroy the trouts of a stream, by confining 
 them in a small portion of their watery element, 
 until it became a dirty putrid puddle, or as we 
 should distress and injure them by confinement 
 and privation in less degree, so do we destroy or 
 injure human beings, when we too closely confine 
 around them a portion of their aerial element. 
 The arts of life and usages of society have led, in 
 many parts of the earth, to the practice of forming 
 apartments, which thus confine the air ; but, 
 because the air, become unfit for breathing, is 
 still as invisible as before the change, and the 
 cause of the consequent distress and disease is 
 not obvious, it has been, and still is, in innu- 
 merable instances, allowed to continue working 
 its fatal results, without awakening suspicion.
 
 58 ON VENTILATION'. 
 
 Science, however, having at last detected the 
 concealed destroyer of so much life, and health, 
 and happiness, the mass of the people are begin- 
 ning to deal with it as it is befitting. A striking 
 instance of popular ignorance with respect to this 
 subject, and of mischievous practice founded upon 
 that ignorance, was to be witnessed very lately, 
 if it is not still, in Buckinghamshire, among the 
 poor girls who gain their livelihood by lace- 
 making. To save the expense of fire, they were 
 wont, in winter, to choose, among the rooms 
 belonging to their families, the smallest, which 
 would contain to the number of twenty or thirty 
 of them, and there to congregate, and keep them- 
 selves warm by their breathing. The odour of 
 their breaths, although unperceived by themselves, 
 soon became, to a stranger entering, exceedingly 
 offensive. The pale faces, broken health, and early 
 deaths, of many of the ignorant self-destroyers, 
 told, to a better-informed observer, what they had 
 been doing ; but it was very difficult to convince 
 themselves of their folly. Proving how much is 
 yet to be done, to inform the public sufficiently 
 on this subject, I need only add, that even now, 
 many schools, manufactories, churches, ball-rooms, 
 courts-of-law, and other rooms of assembly, are, 
 for hours together, in a state little better than the 
 rooms of the lace-workers above described ; indeed, 
 sometimes in a worse state, as shown by the car- 
 rying out of persons fainting and half suffocated, 
 and the cry among the company left for open 
 windows. The scene of death in the Black Hole 
 of Calcutta was the consequence of confinement
 
 OX VENTILATION. 59 
 
 without ventilation, carried not very much further 
 than has been witnessed for a short time in some 
 voluntary English crowds. 
 
 77. Until lately, the necessity for ventilation, be- 
 yond what chimneys, and the openings of doors 
 and windows produced, was in very few cases sus- 
 pected ; and one mischievous error of many persons 
 was their deeming cold air and pure air the same : 
 so that, if a school-room, with children, was by 
 them found to be cold in a winter's day, it was 
 supposed to be at least well ventilated. It is a 
 remarkable fact, that the first accomplishment of 
 perfect ventilation for a crowded place was not, as 
 might have been anticipated, in the houses of the 
 great and learned, and therefore in our houses of 
 parliament, or in the churches of the wealthy, or 
 in fashionable assembly-rooms of any kind, but in 
 the cotton-factories. In the first- mentioned places, 
 it is true, that openings were made in the ceilings 
 and side walls, and cowls were placed over the 
 openings, or fires or strong lamps were placed 
 within them, to rarify the air, and cause it to 
 ascend ; but as, in all these cases, the important 
 object was trusted to the working of invisible 
 draughts or currents which might not take place, 
 and which, very often, from unsuspected coun- 
 tervailing influences, did not take place aright, 
 the object was most imperfectly accomplished. 
 It was in the cotton factories that fan-wheels 
 were first set in motion, which, by a certain speed 
 of revolution, were known to extract a certain 
 quantity of air. The happy effects of this mecha- 
 nical ventilation on the health of the operatives
 
 60 OX VENTILATION. 
 
 have been loudly proclaimed by various observers. 
 The earlier introduction of mechanical ventilation 
 into the factories probably sprung from there being 
 already in them steam-engines constantly at work 
 to move any apparatus, and persons who had 
 previous knowledge of fan-wheels used for other 
 purposes. 
 
 78. Mechanical ventilation once introduced 
 would have been already much more common 
 than it is, but for a great and very costly error 
 made in all the apparatus hitherto employed to 
 effect it an error arising from inattention to a 
 grand principle or truth in natural philosophy. 
 That principle is, that in giving motion to any 
 fluid, (water, or air, for instance,) the force re- 
 quired is as the square of the velocity : that is to 
 say, must be increased four times to give double 
 velocity, nine times to give triple velocity, one 
 hundred times to give ten times the velocity, and 
 so forth. Thus, water jetting from an opening in 
 the side of a vessel, one foot below the surface, 
 has a certain velocity depending on the pressure of 
 the one foot of water over it, and that the jet may 
 have a double velocity, it must issue from an open- 
 ing not two feet, but four feet below the surface, 
 and so on ; the reason being, in the case supposed, 
 that there are not only twice as many particles of 
 water moved or driven out, which costs double 
 force, but each particle is made to move twice as 
 fast, that twice as many may pass through in the 
 same time, which costs another doubling of the 
 force, and the two doublings make four times the 
 original amount. We shall now view this law as
 
 OX VENTILATION. 61 
 
 regulating- the motion of air. If in a house there 
 were a passage fifty feet long by ten feet high and 
 wide, quite open to the atmosphere at the two 
 ends, a child who could easily push along on the 
 smooth level bottom of the passage a common 
 wheel-chair or small carriage, could, in a calm 
 day, push the same along with almost equal ease 
 although a sail were hoisted upon it very nearly 
 filling the passage, as a piston fills a pump-cylin- 
 der, but without absolute touching or friction, and 
 by so doing he would push all the air which were 
 in the passage (5,000 cubic feet in the case sup- 
 posed) out at one end of it, while an equal quantity 
 entered at the other. And if the passage were over 
 the ceiling of the House of Commons, and were 
 made to take its new air always from the body of 
 the house, while it threw the old into the atmos- 
 phere, the child, by walking backwards and for- 
 wards a few times, would have changed the whole 
 air in the House of Commons. In the case sup- 
 posed, the effort required to move forward the 
 sail or piston, would be little more than would move 
 a large expanded umbrella forward in a calm, 
 and merely enough to overcome the inertia of the 
 mass of light air. But if the supposed passage, 
 instead of being quite open to the air with an 
 aperture or section at both ends of one hundred 
 square feet, were closed at one end by a wall in 
 which there were an opening of only one foot 
 square, evidently the air in the passage, to be 
 driven out in the same time, would have to move 
 through the opening of one foot a hundred times 
 faster than through the opening of one hundred
 
 62 OX VENTILATION*. 
 
 feet, and would cause to the child or other power 
 propelling it, merely from the different mode of 
 moving it, an expenditure of one hundred times 
 the force to displace the same quantity in the 
 same time. And if the quantity of air expelled in 
 the same time were increased, the loss of force 
 would be as the square, in the way above ex- 
 plained. If farther, the air were both expelled 
 from the passage by a small opening, and drawn 
 into it by a similar opening, the waste of force 
 would be again doubled. The air might be said, 
 in any such case, to be " wire-drawn," both on 
 entering and on leaving the passage, and the 
 obstruction would be of the same kind as if, in one 
 of the great water-pipes for the supply of a 
 city, a strong plate or partition were somewhere 
 placed across the pipe, with a small hole in it, 
 through which all the water should be squirted. 
 The striking difference of power required in such 
 a case is experimentally felt by a person who, 
 with a common fire-bellows, first suddenly draws 
 in or expels its fill of air through the large valve 
 behind held open, and then tries to draw in or 
 expel the air in the same time through the small 
 opening of the nozzle. He may crack the leathern 
 cheeks of the bellows, and exhaust his own strength, 
 in the fruitless attempt. The quantity of air 
 moved in both cases would be the very same, but 
 there would be a difference in the size of the 
 opening. Now in all the modes of mechanical 
 ventilation which I have seen, except that by a 
 chimney to be noticed below, which has a fault 
 of another kind, the error above described of
 
 ON VENTILATION". 63 
 
 wire-drawing the air has been signally committed, 
 and the force wasted therefore in accomplishing 
 the object has been very great. Some of the 
 fan-wheels, the agency of all of which, from being 
 oblique, is wasteful, are made to revolve many 
 hundreds of times in a minute, and to force the 
 air through a narrow passage, expending thus the 
 power of one or two horses, where the weight 
 which moves a great clock, would do almost as 
 well. 
 
 79. That in regard to ventilation, which subject 
 has but lately engaged philosophic attention, the 
 expensive error here spoken of should have been 
 committed, is not so remarkable as that, from igno- 
 rance or neglect of the same principle in natural 
 philosophy, the prodigious amount of steam-power 
 at work in the mines of Cornwall, should for many 
 years have been in great part used to waste. It is 
 a fact discovered less than two years ago, that the 
 numerous Cornish engines, among which there are 
 single ones of 600 horses' power, had been for nearly 
 twenty years, although under the eyes and direc- 
 tion of some of our most experienced engineers, 
 working to produce often scarcely a half or a third, 
 or even in some cases, a fourth of the effect which 
 they were equal to owing to the steam having 
 been sent from the boilers into the working cylin- 
 ders through openings so small, that the power was 
 expended in the passage, like the power of a hand 
 forcing air through the nozzle of a bellows. The 
 error was, I believe, discovered by a kind of acci- 
 dent ; but its nature was at first so far from being 
 scientifically apprehended, that the early reports
 
 04 OX VKXTILATIOX. 
 
 of increased performance from correcting it, were, 
 by persons deemed good judges, called lies and 
 imposture ; and even now, although wide channels 
 are generally provided for the steam, I have not 
 seen the case referred to the general law which 
 ascertains the precise amount of loss or gain. The 
 two errors, in respect to ventilation and steam- 
 power, here cited, prove of what importance to 
 general education or, at any rate, to all profes- 
 sional education it is, to include, in the course 
 of study, a knowledge of those general laws of 
 Physics or Natural Philosophy, which explain the 
 great phenomena of nature, and which alone can 
 direct aright the proceedings of men in the various 
 arts of life. 
 
 80. From what has been said above, it will be 
 seen that a box or case, cylindrical or square, for 
 a pump-body, with a loose piston, very nearly, 
 but not quite, rilling the body, so as to move in it 
 almost without friction, and with valved openings 
 nearly as large as the area of the pump, is the best 
 blowing or exhausting machine for ventilation ; 
 and there may be a single pump, or two united, 
 to be worked by a single or double crank and 
 weight, or any of the numerous modes of giving 
 the required reciprocating motion. Such a pump 
 answers not only for extracting foul air, but also 
 for forcing in pure air where wanted. It may be 
 fixed in position, or may be a moveable piece of 
 furniture, to be used, for instance, to draw air 
 from the top of a window opened on a ball- night, 
 or from an opening in the wall concealed from view 
 by a picture-frame. By such a pump, air of perfect
 
 ON VENTILATION. 65 
 
 purity, and in any quantity, may easily be sent 
 from any neighbouring situation, as from the top 
 of a lofty tower, to supply a dwelling placed where 
 unwholesome exhalations might enter by the doors 
 and windows. 
 
 81. The mode of ventilation by a chimney, al- 
 luded to above, in which mode the air is not wire- 
 drawn, is exemplified in mines, where a large fire, 
 placed at the bottom of one upright shaft or open- 
 ing, converts it into a chimney, in which a bulky 
 column of hot air is constantly ascending, to be 
 replaced by a corresponding quantity of cold pure 
 air, descending by other shafts to ventilate the 
 mine. An instance of the same mode of moving 
 air has lately been exhibited in the temporary 
 British House of Commons. By the side of the 
 building is placed a great round chimney, 120 
 feet high, by 11 feet wide at bottom, and 8 feet 
 wide at the top, with a fire-grate near the bottom, 
 having 25 square feet of bars or surface, and 
 therefore big enough for a steam-engine of 25 
 horses' power. A passage, as wide as the chimney, 
 leads to its bottom or fire-place, from a space 
 over the ceiling of the House, into which the 
 impure heated air from the House enters freely 
 by many openings ; and, when the fire is lighted, 
 the air which supplies it, and which becomes the 
 rising column in the chimney, is the impure 
 heated air spoken of, a corresponding quan- 
 tity of fresh air of course entering the House 
 below. The chimney thus becomes a kind of 
 pump, but worked at the expense of many horses'
 
 G6 ON VENTILATION. 
 
 power, to effect what a ventilating pump, made 
 on the principle above described, and worked by 
 a power of one horse or less, would even more 
 certainly perform. The mechanical force of such 
 a chimney is the difference of weight between the 
 mass of heated air in it, and an equal bulk of 
 the external air, which difference in this House of 
 Commons chimney, in an ordinary winter day, 
 is a pressure less than two hundred pounds. 
 Advantages of a proper ventilating pump in such 
 a case would be, a great saving of original ex- 
 pense, a saving of fuel ever afterwards, and that 
 there would be means of knowing, to within a few 
 gallons, the quantity of air changed. 
 
 82. There is, with respect to ventilation, a popular 
 misconception and erroneous practice, of a nature 
 the opposite of the total neglect described in 
 former paragraphs. Because ventilation is impor- 
 tant, there are persons not satisfied with enough, 
 but who demand , at heavy sacrifices, what is excess. 
 It would be a similar error, if a man, from knowing 
 that water is a necessary of life, should abandon 
 the never-failing well in his garden, and his con- 
 venient home, that he might drink always from 
 the Nile or the Ganges. A man needs, per minute, 
 as explained in Article 10, the oxygen of one- 
 sixth of a cubical foot of atmospheric air ; but, 
 because of the mixture of his breath with the air 
 around him, he requires, to be safe, a ventilation- 
 supply of from two to three cubical feet per minute. 
 Now the ordinary workmanship of house-builders 
 in England leaves, as crevices around doors and
 
 OX VEXTILATIOX. 67 
 
 windows, passage for many times three gallons per 
 minute, besides that there is the powerful ventila- 
 tion of the frequent openings of the door, when per- 
 sons come and go. Yet there are in England many 
 persons, who, under all circumstances, call out 
 for open fires and open windows, and by the cold 
 currents and other concomitants of a ventilation 
 twenty or a hundred times more than neces- 
 sary, prodigiously waste fuel, and injure or kill 
 their children and friends, by catarrhs, rheuma- 
 tism, pleurisies, &c. To these persons it must ap- 
 pear wonderful, that in Russia, where, all through 
 the winter, there are only close stoves, and dou- 
 ble windows, carefully closed, and no provision 
 made for ventilation, beyond accidental crevices, 
 the people are very healthy, and more indivi- 
 duals attain a very advanced age, than in al- 
 most any other country in Europe. In a room of 
 twelve feet in all its dimensions, and containing, 
 therefore, 1728 cubical feet of air, there is, with- 
 out any ventilation whatever, an allowance of two 
 feet a minute for one person, for more than fourteen 
 hours. 
 
 83. Double-current warm ventilation. I have 
 now to describe a new mode of ventilating, by 
 which the hot impure air, as it passes away, is com- 
 pelled to give up its warmth to the pure air en- 
 tering to take its place. I had ascertained the 
 principle many years ago, and I have in my 
 " Elements of Physics" explained it by the case, 
 that if a quantity of boiling water be placed in a 
 vessel, a, and be allowed to run along a very thin 
 
 F2
 
 68 ON VENTILATION'. 
 
 metallic tube, from a to d, where it escapes with 
 
 7 
 
 speed regulated by the cock at d ; and if, at the 
 same time, an equal quantity of cold water be 
 placed in the vessel, b, and be allowed to run 
 along a larger tube, b, c, including or enveloping 
 the other, to escape by the cock, c ; the hot water 
 from a, losing, every instant, a little of its heat to 
 the counter-current of colder water surrounding it, 
 will, when it arrives at d, be only one degree 
 or even less hotter than the quite cold water 
 descending from b; while, on the other hand, 
 the originally cold water from b, acquiring every 
 instant, in its passage along the tube, b, c, heat 
 from the tube of hot water within it, will, when 
 at last discharged, be onlyby one degree or less 
 different from the boiling water issuing from the 
 vessel, a. Thus, by making the two currents run 
 counter to each other, in almost mixed contact, 
 there is not, as in former processes, merely a 
 mixture of two temperatures producing an average 
 temperature, but the whole excess of heat of the 
 one is given, with very trifling loss, to the other ; 
 and the hot water, which might be the foul water 
 of a bath just used, has become the cold water; 
 and the cold water, which might be pure water 
 for a bath intended, has become the hot. Now 
 the same transference of heat takes place, where
 
 ON VENTILATION. 69 
 
 the counter-currents are of any other fluid, of 
 air, for instance, instead of water, as many persons 
 had occasion to witness, four years ago, in Erick- 
 son's air-engine ; and, therefore, the very heated 
 impure air, which accumulates at the top of an 
 enclosed space containing a crowded assembly, 
 may, as it passes away under the influence of a 
 ventilating pump, be made to give up its whole 
 warmth, or as much of it as desired, to an equal 
 quantity of pure air, entering from another pump. 
 And where there may be a considerable number 
 of persons present, no other heating apparatus will 
 be required but the lungs of the company. This 
 mode of warm ventilation is applicable generally 
 from the case of an assembly of thousands of per- 
 sons in a church or theatre, through the descend- 
 ing series of courts-of-law, ball-rooms, schools, 
 sitting-rooms, even to that of a single person, 
 who, wherever placed, may send out his warm 
 breath through one tube, to warm the pure air 
 drawn in through another tube, surrounding the 
 first. The application of the apparatus to particular 
 cases will be more minutely described below. 
 
 84. This process, for transferring heat from im- 
 pure air about to be dismissed into the atmosphere, 
 to pure air about to be applied to use, will, by 
 many readers, be deemed quite new ; and yet, in a 
 less perfect form, it has been a popular practice in 
 Europe from time immemorial. When a person, 
 going out of his house into the cold air of winter, 
 ties a bulky woollen handkerchief, called " fear- 
 nothing," around his neck and face, or holds any 
 such porous mass over the mouth, that he may
 
 70 ON VENTILATION. 
 
 breathe through it, he is really applying the same 
 principle. His warm breath, going out through the 
 handkerchief or other mass, warms it, and then 
 the cold pure air, drawn towards the mouth through 
 the heated mass, absorbs a great part of the retained 
 heat, .and enters the chest of the individual much 
 less cold than the air of the atmosphere around. 
 The hackney-coachmen of Paris are rarely seen 
 in winter, without such a defence; and in all 
 countries, medical men commonly desire patients, 
 with tender chests, not to pass, even from one 
 room to another, through a cold staircase, without 
 such protection. Lately, a useful modification of 
 this simple process has been presented to public 
 notice, by a medical practitioner returned from 
 India. He substitutes, for the bulky handker- 
 chief, or texture of common thread, a less bulky 
 texture, yet more heat-absorbing, of metallic 
 thread or wire in fact, folds of fine wire-gauze, or 
 pierced plates of metal, which when fixed in a 
 light frame, form a compact mouth-piece fitting 
 closely around the lips, and leaving free passage 
 for the air between the numerous apertures. The 
 folds or plates are heated by the warm breath going 
 out, and then give up the heat so acquired to the 
 pure air going in. The contrivance may be called 
 the fear-nothing of metal, and it has the advantages 
 of being less bulky, of retaining less of the impure 
 air in it, and of allowing speech to be heard 
 through it, almost as if there were no interruption. 
 The effect of any means of this class is to give 
 in reality an artificially warmed atmosphere to a 
 person walking out in the open air, as if he were
 
 OX VEN 7 TILATION T . 71 
 
 still in his room heated by a fire. It may be called 
 a portable warm room, or a suit of warm clothing 
 for the lungs. It affords a valuabje security to 
 persons labouring under certain kinds of weakness 
 or disease of the chest, and who are compelled by 
 their duties to leave home ; and it will allow many 
 persons who, without it, would be confined to 
 their rooms all the winter, to walk abroad with 
 impunity. It is an addition made by art, to the 
 beautiful provision already existing in nature, of the 
 long narrow channels of the nostrils and throat, 
 which have considerable effect, by their warmth, 
 in tempering the air which passes through them 
 to the lungs. The arrangement of metallic threads 
 or plates, forming the air-warming mouth-piece, 
 has been called, by the proposer, a respirator, and 
 has been made the subject of a patent. We may 
 regret that, in this country, there should be no 
 other provision for rewarding men who make 
 useful suggestions, but by allowing them, even 
 where the public health is concerned, to levy a 
 tax, and which often falls heavily on persons who 
 can little afford to pay it. In the present instance, 
 a great many of the persons needing any new 
 means of relief will be among the poor, already, 
 perhaps, suffering from want of clothing and fuel ; 
 and the price charged for the first of the wire- 
 gauze instruments was so high, that only the rich 
 could afford to buy them : they are now cheaper. 
 We may remark, with respect to the wire-gauze, 
 that the temperature of the air inspired through it 
 is very unequal, being much higher at the com-
 
 72 ON VENTILATION. 
 
 mencement of the inspiration than towards the 
 end, when the metal has already given up nearly 
 all its heat. But a perfect uniformity of tempera- 
 ture is obtainable, by using a suitable modification 
 of the double-current apparatus, of which I have 
 spoken above. For this purpose is required a 
 mouth-piece, from which one or more tubes, of 
 thin metal, or other substance, may carry the hot 
 breath to the atmosphere, and to which another, 
 larger tube, surrounding the first, may bring pure 
 air from the atmosphere, the currents being kept 
 quite distinct by simple valves in the tubes. The 
 warmth of the departing air will thus be given to 
 the coming air, and the degree of warmth retained 
 will depend on the length of the tubes, or on 
 the action of a valve placed over a lateral open- 
 ing in the outer tube, near the mouth-piece, and 
 made obedient to a thermometer. Thus also will 
 uniformity of temperature be secured. The appa- 
 ratus may be made to resemble a cane held 
 to the mouth, or a Turk's pipe, or may bend round 
 the neck, and be concealed in a cravat. Because 
 twice as much heat issues with the breath as is 
 wanted again, a person will not lose the advantage 
 of the apparatus, by detaching his mouth from it 
 occasionally, to take his part in an ordinary con- 
 versation. A mode, recommended by me in the 
 " Elements^ many years ago, of keeping and using 
 the warmth of the breath, was an extension of 
 the common practice of blowing into one's hands 
 covered with gloves, to warm them ; namely, for 
 persons going to bed with cold feet, which would
 
 ON VENTILATION". 73 
 
 probably keep them awake for hours, and spoil 
 their night's rest, to send their warm breath down 
 to the feet through a tube. 
 
 85. One other modification of the principle of 
 transferring heat may be mentioned ; namely, to 
 cause the pure air, entering a building for ventila- 
 tion, to pass through a long subterranean passage ; 
 in winter, there to absorb a portion of the pre- 
 ceding summer's heat still remaining in the earth 
 around the passage; and in summer, there to 
 give a portion of its heat to the earth. This method 
 has been found to raise or depress the tempera- 
 ture of the entering air from ten to fifteen degrees. 
 
 86. We may here observe, how applicable the 
 double-current apparatus is to the purpose of 
 drying substances. In the air of a room full of 
 damp recently printed paper, or of wet linen, 
 evaporation or drying takes place only until the 
 air be saturated with moisture, and then stops; 
 but if the moist hot air be sent away, and caused 
 to give its heat to dry air entering, the new air 
 will take a second load of moisture, and on going 
 away, will leave its heat to aid in taking a third, 
 and so on. 
 
 GIVING MOISTURE TO AIR. 
 
 87. Our atmosphere contains besides the two 
 constant elements, oxygen and nitrogen also a 
 variable quantity of moisture or aeriform water. 
 This is constantly rising into it, under the influence 
 of the sun's warmth, from the exposed surfaces of 
 water on earth, to descend again, where required
 
 74 GIVING MOISTURE 
 
 by animals and vegetables, in the forms of rain, 
 mist, dew, &c. Even while invisible in the atmo- 
 sphere, too, it is supplying essential wants of 
 animals and vegetables, as is discovered particu- 
 larly when the air as in the African simoom, 
 and other dry winds is nearly devoid of it, and 
 then withers up and blights vegetable nature, 
 and much distresses animals. The quantity of 
 water sustained invisibly in air has a proportion 
 to the temperature of the air ; and when the air 
 has not its due proportion as when clear frosty 
 air is heated, without addition of moisture it 
 is felt to be dry, and powerfully absorbent of 
 moisture. To make the atmosphere of a winter 
 room, therefore, congenial to man's nature, it is 
 generally necessary to give it a proportion of 
 moisture as well as of heat. This is easily done, 
 by placing, on or near the thermometer-stove, 
 a vessel containing water, into which a piece 
 of linen or cotton cloth, hanging from any fit 
 support, may dip. The cloth, by absorbing the 
 water, as a lamp-wick absorbs oil which it does 
 more readily for having been dipped into a solu- 
 tion of potash is always wet, and giving out 
 moisture to the air. The quantity may be deter- 
 mined by the extent of cloth exposed, and may be 
 varied by what a sailor would call letting out or 
 taking in a reef. A surface of six inches square 
 will suffice for an ordinary room. The suspended 
 cloth may be concealed from view by any graceful 
 screen, as by a tower-shaped cover of porcelain, 
 open above and below, to favour the passage of 
 air. Invalids, requiring to pay particular attention
 
 TO AIR. 75 
 
 to this point, may be directed by a hygrometer, 
 which will always declare the exact degree of 
 moisture existing in the air. As in England, be- 
 tween a north-east wind which, to most persons, 
 is so disagreeable, and to many so hurtful and a 
 south-west wind, of the same temperature which, 
 on the contrary, is, to the sense of almost every 
 body, bland and refreshing the chief, if not the 
 only difference, is the proportion of moisture ; 
 means which enable us to control the moisture as 
 well as the temperature of the air, may almost be 
 called means of calling up at will, or of manu- 
 facturing, a south-west wind. 
 
 88. Having now described generally the new 
 stove, by which it is possible very economically to 
 obtain any degree.of pure warmth required, and the 
 new process of ventilation by the single or double 
 current, which secures the wished-for change of 
 air, without wasting the heat already in the 
 building, and the mode of regulating the moisture 
 of the air in a building, by the exposure of wet 
 cloth, we proceed to consider, in detail, first, the 
 simplest and most common case of warming and 
 ventilating, namely, that of a common sitting- 
 room ; and we shall afterwards, from that as a 
 standard and example, pass to describe the 
 management of the other most important cases, 
 as of school-rooms, churches, courts-of-law, &c. 
 It is to be said, however, that the object is only 
 to explain the general principles, and not to give 
 working directions to persons unacquainted with 
 the principles. The subjects of warming and ven- 
 tilating, although in themselves simple, still deal
 
 76 WARMING AND 
 
 with things and motions which are impalpable 
 and invisible, and must be studied in their princi- 
 ples to be understood at all. Where the bodily eye 
 can see nothing, the mind's eye must see important 
 processes. The peculiarity of the subject is proved 
 by the fact of so many distinguished architects and 
 engineers failing signally in undertakings to warm 
 and ventilate. 
 
 WARMING AND VENTILATING. 
 An ordinary Sitting- Room. 
 
 89. An ordinary sitting-room, or any apartment 
 of moderate size, occupied by a family of a few 
 persons, will be easily warmed by one thermo- 
 meter-stove, of dimensions calculated by the rule 
 given at Art. 37. The stove gives out its heat 
 partly by radiation all around it, but chiefly by 
 warming the air which touches it. This air then 
 ascends, and spreads over the ceiling, warming 
 that, and soon by downward radiation from the 
 ceiling, and farther motion and mixing of the air, 
 from the descending currents produced because 
 the walls absorb the heat of the air which touches 
 them, the whole room is more or less equably 
 warmed. The difference of sensation experienced 
 by a person entering a room heated to a certain 
 thermometric degree by a stove, and a room heated 
 to the same degree by an open fire, depends on 
 the air being somewhat warmer, and the walls 
 somewhat colder, in the first room than in the 
 second. A small stove, at a high temperature,
 
 VENTILATING. 77 
 
 gives out as much heat as a large stove at a low 
 temperature ; but there are great advantages in 
 using a stove of full size, as, that its moderately 
 heated surface cannot injure the air of the room 
 that there is economy of fuel, because the air, 
 leaving it towards the chimney, carries less heat 
 to waste, and that it acts more steadily from being 
 less quickly either heated or cooled. 
 
 90. Sufficient ventilation for an ordinary sitting- 
 room will be ensured, in a cold winter day, 1st, 
 by the demand of air for the combustion in the 
 stove ; 2dly, by the considerable change occurring 
 through the crevices around doors and windows, 
 which may be taken at about six cubical feet a 
 minute for each ; and, thirdly, by the hundreds 
 of gallons of fresh air, which, every time the door 
 is opened, enter and displace an equal quantity of 
 the air previously in the room. In warmer weather, 
 when the difference between the external tempera- 
 ture and that of the room is less, and there is, 
 therefore, less tendency to spontaneous change, 
 some additional means may be used from among 
 those to be described hereafter. But the three 
 already mentioned have so considerable an effect, 
 that even in Russia, where they are the only means 
 in common operation, and where they are counter- 
 acted very much by double doors and windows, 
 and the closest fittings every where, in rooms 
 without an open fire-place, and heated entirely by 
 the action of stoves which are fed with air from the 
 lobbies or passages, they still are sufficient. This is 
 proved by the ruddy, healthy countenances and 
 long lives of the persons dependent upon them.
 
 78 WARMING AXD 
 
 91. The same sitting-room in a warmer day, or 
 when occupied by a more numerous company, or 
 when the stove has been allowed to be too active, 
 requires for sufficient ventilation to have one or 
 more openings near the ceiling. In many cases, it 
 answers well merely to lower, a little, the upper 
 sash of a window. This is done not so much to 
 allow the most heated and impure part of the air 
 to escape, as to have a light column of a certain 
 altitude within, yielding to the pressure of the cold 
 air outside; for it is to be observed, that the cir- 
 culation, or mixing of air in a winter room, with 
 only a few people in it, is so rapid, owing to the 
 upward motion around the stove, and the down- 
 ward motion near the colder walls and windows, 
 that the ventilation is about equally perfect from 
 whatever part the air be taken. Where a room has 
 an open chimney, such an aperture as now spoken 
 of, instead of allowing impure air to escape, be- 
 comes an inlet for cold air to supply the upward 
 action, or draught of the chimney, which cold air 
 pours directly down upon the heads of any persons 
 sitting near the opening. But with the stove, as 
 more fresh air than is required for the stove finds 
 easy entrance by the ordinary imperfect fittings of 
 the door and windows, there is always a sufficiency 
 to force out the heated air through any opening 
 near the ceiling. 
 
 92. Where the company in a room is so numerous 
 that very much air must be allowed to escape 
 above, and, consequently, as much to enter below, 
 the air which enters in cold weather, should be 
 admitted through a passage expressly calculated for
 
 VENTILATING. 79 
 
 it, and leading it into contact with the stove so as 
 to give it the desired temperature, before it spreads 
 in the room. And there is a general direction, 
 that any hot air entering a crowded room, should 
 be less heated by two or three degrees than the 
 air of the room, for otherwise, it will at once 
 ascend to the ventilating holes, and thus be use- 
 less to the company as a warming medium, and 
 hurtful by preventing the proper ventilation. 
 
 93. In a room or suite of rooms frequently used 
 for assemblies of persons, there would be saving of 
 fuel as well as the most complete ventilation, by 
 using the apparatus for the double current, de- 
 scribed at Art. 82, by which the hot impure air, on 
 leaving the room, is made to deliver its desirable 
 warmth to the pure air entering, and thus saves 
 all expenditure of fuel after the company has met. 
 This double-current apparatus in an ordinary 
 dwelling-house might consist of a certain number 
 of small very thin metallic tubes, leading the hot 
 air from near the ceiling towards the external 
 atmosphere, and which would be included in a 
 larger outer tube, of which the office would be to 
 carry pure air into the room ; and currents would 
 be produced in the two directions by suitable ven- 
 tilating pumps connected with the tubes, the one 
 extracting, the other propelling, and both moved 
 like a kitchen-jack, by a weight wound up from 
 time to time, or by any other power. The expense 
 of the apparatus would be trifling, and the result 
 of extreme importance. 
 
 94. If a room be very large, one stove to heat 
 it must be of dimensions to correspond, or must
 
 80 
 
 WARMING AND 
 
 have a considerable length of flue exposed in the 
 room, or more than one stove must be used in the 
 same room. The common objection to two or more 
 open fires in one room, or in freely communicating 
 rooms, that one of the chimneys acting more power- 
 fully than another, may overpower the other, as the 
 long leg of a syphon overpowers the short leg, 
 and cause it to throw its smoke into the room, can 
 never apply to the stoves which require so little 
 air, and which never smoke. If one stove of large 
 surface be preferred to a number, it would be better 
 to increase the surface by connected tubes or wings 
 
 as here shown, in the form of three pillars, or by 
 some other equivalent modification than to have 
 one very bulky simple box. The fire at the bottom 
 of the central pillar would keep up a rapid cir- 
 culation of hot air in the three. If such tubes were 
 made to extend far from the central box with little 
 ascent, the motion of the hot air in them would be 
 very languid, unless it were quickened by an air- 
 moving contrivance, such as a small fan-wheel 
 included in the circuit ; but with such an addi- 
 tion, air might be sent to any distance, and in any 
 direction from the central box, just as is true of
 
 VENTILATING. 81 
 
 hot water or steam. The ease with which air in 
 pipes is moved with moderate velocity, is seen 
 in the steady supply of gas to lamps, throughout 
 awide district, produced by a very trifling force at 
 the central gas-holder. The objection to using the 
 fan-wheel for ventilation, does not apply to this 
 case, where the required motion is so slow. 
 
 95. Instead of having a fire for each room, all the 
 rooms of a house, however numerous, may be per- 
 fectly warmed and ventilated by a single apparatus ; 
 and there are cases where this plan would be pre- 
 ferable to separate stoves. A channel branching 
 to every room, would carry air of the desired tem- 
 perature from one convenient station, where it 
 would be heated by a suitable thermometer-stove, 
 and from whence it would be propelled by a suit- 
 able ventilation- pump. The discharge of air into 
 the several rooms would be regulated by sliding- 
 shutters in the apertures from the pipe, and as the 
 propelling force would be uniform and certain, the 
 effect would be equally certain, and therefore very 
 different from what is seen where the production 
 of currents has been trusted to the comparative 
 lightness of the heated air. To increase the surface 
 of a stove for such a purpose, tubes would be 
 added to it, arranged possibly in the form of a 
 gate or railing with hollow bars, or in other forms 
 equally appropriate ; or a set of flat pipes, re- 
 sembling folio volumes standing a little apart, like 
 those used in the apparatus for heating air by 
 water, would answer. The water-apparatus men- 
 tioned, if governed by a thermometer-regulator, 
 although requiring more fuel, might, by some, be 
 
 G
 
 82 WARMING AND 
 
 preferred. Such an apparatus, while warming, 
 would also be ventilating. The double-current 
 ventilating apparatus, to save heat, might be 
 adopted here too, if desired. 
 
 96. In all rooms where we wish to have cheap, 
 equable warmth, double windows should be used : 
 they save much heat, or fuel, as stated at Art. 39, 
 and they prevent the cascade of chilled air, which 
 is always pouring down where the air of a room 
 has, between it and the freezing atmosphere, only 
 one thin film of glass. This cold cascade is so 
 remarkable, that persons not well informed be- 
 lieve it generally to come through some opening, 
 which they cannot discover, about the window. 
 Cold glass absorbs heat so rapidly from all bodies 
 exposed to it, that it seems to radiate cold in the 
 same manner as the stove radiates heat. The inner 
 glass of double windows never becomes very cold. 
 In northern continental Europe, double windows 
 are universal. 
 
 97. Double doors also, for the room of an invalid, 
 are of great use in very cold weather, by prevent- 
 ing more of the air of the room from being changed 
 by once opening, than what remains between the 
 doors. 
 
 98. To ventilate a room in summer, an apparatus 
 to extract air from near the ceiling, while fresh air 
 were admitted near the bottom of doors or windows 
 left a little open, would be the perfect plan. But 
 in many cases there would be no hazard to the 
 health of the company, from effecting the whole 
 ventilation by opening some of the windows a 
 little at top, and others at the bottom : yet it is to
 
 VENTILATING. 83 
 
 be recollected, that strong currents even of warm 
 air, are to many persons dangerous. 
 
 9.9. To fit the apparatus described under this 
 head, for the purposes of warm climates, where 
 coolness has to be artificially sought instead of 
 warmth, it will be necessary only to substitute cold 
 surfaces instead of warm surfaces in the situations 
 where the air is passing towards the rooms. The 
 surfaces may be the exterior of vessels containing 
 iced water, or water which has just dissolved salt- 
 petre ; or, may be the interior of tubes, kept wet 
 and cold externally by evaporating water. The 
 rooms should have the doors and windows closed, 
 so as not to interfere with the intended currents. 
 
 To warm and ventilate a School-room. 
 
 In accordance with the principles now ex- 
 pounded, the peculiar management of this case 
 will be : 
 
 100. Before the arrival of the children, to warm 
 the room gradually to near 60, by a sufficient 
 amount of stove surface within the room. During 
 the warming, the doors, windows, and ventilating 
 openings to be all closed, that there may be no 
 useless expenditure of pure warm air. If, to 
 save time in heating, the room be warmed more 
 suddenly by a stove at so high a temperature as 
 injuriously to affect the air, then just before the 
 arrival of the children, the action of the stove must 
 be slackened, and the. windows must be opened 
 for a moment, to change completely the air of the 
 room. The warmth in the walls will then soon 
 be communicated to the fresh air last entered. 
 G 2
 
 84 WARMING AND 
 
 101. During the presence of the children, to 
 ensure proper ventilation either by simple open- 
 ings in or near the ceiling, or by openings feeding 
 a ventilating-pump, the supply of pure air to enter 
 below, through passages which carry it into con- 
 tact with the stoves, and so give it the required tem- 
 perature; or both the ventilating and warming 
 to be effected by the double-current apparatus set 
 in motion after the room is heated. 
 
 102. If the room be warmed at first, or before 
 the arrival of the children, by a current of hot air 
 coming from an external stove, that air should 
 enter near the ceiling, and all high ventilating 
 openings being closed, should displace the cold 
 air by openings below, and should itself gradually 
 fill the room from above downwards. As soon as 
 the children arrived, the process should change 
 by ventilation commencing above, and moderately 
 heated air entering below. 
 
 103. In summer, sufficient ventilation might be 
 ensured by many small openings in the room 
 both above and below, or by the upper sashes of 
 the windows lowered, and the lower sashes raised 
 a little and if some of the openings were not to 
 windward, a ventilating-pump should be used. 
 The want of proper ventilation in schools is most 
 mischievous. While the children are breathing 
 hot polluted air, their minds suffer as well 
 as their bodies, and they study with little profit ; 
 and this is true of all persons similarly circum- 
 stanced.
 
 VENTILATING. 85 
 
 Concert or Assembly-rooms. 
 
 104. These require stoves with closed passages 
 until the company meet, and afterwards ventila- 
 tion by simple openings, or openings with a ven- 
 tilation-pump above, while warmed air enters 
 below : or there may be ventilation and heating 
 together, by the double-current apparatus. Many 
 of the head-aches, &c. which persons suffer after 
 attending crowded lectures or exhibitions, are 
 consequences of the impure air breathed. 
 
 Courts -of -Law. 
 
 105. In these the perfect accomplishment of 
 the object should be aimed at, for they are often 
 occupied in the most crowded manner for whole 
 days together. They should be heated first by a 
 large stove on the floor, or rather by warm air 
 sent in through many openings, situated a little 
 above the floor, and afterwards the double-current 
 apparatus should be in constant action. In summer, 
 it would be better to have the ventilating-pump 
 drawing from above, while the inlets below ad- 
 mitted fresh air, than to open windows near which 
 there would be dangerous draughts. The health 
 of many members of the Bar has been destroyed 
 by their spending so much time in badly-ventilated 
 Courts. 
 
 Churcttes. 
 
 106. The warming of the walls previous to the 
 meeting of the congregation, should be continued 
 longer than in other cases, because of the long 
 intervals during which the building is unused.
 
 86 WARMING AND 
 
 The heat should not be great, as people generally 
 go in their walking-dress. Four or six large 
 stoves distributed over the floor, and acting for 
 some hours before the meeting, would warm the 
 seats and walls of any ordinary church, so as to 
 give the desirable temperature. Afterwards ven- 
 tilation would be obtained by openings in the 
 ceiling, and inlets below, for cold air to approach 
 the stoves. The mass of air in a church is gene- 
 rally so great in proportion to the number of the 
 people, and the duration of the service is so 
 moderate, that ventilation is there of less importance 
 than in many other cases. The temperature and 
 dryness of the walls, however, should have strict 
 attention. 
 
 Houses of Parliament. 
 
 107. The mode of ventilating the present tem- 
 porary House of Commons, has already been 
 spoken of at Art. 80 : it is by the action of a vast 
 chimney. It was adopted on the recommendation 
 of Dr. B.D.Reid, the distinguished Professor of 
 Chemistry, and is, perhaps, as yet, the only in- 
 stance in existence of effectual ventilation for such 
 a place. The fresh air, before entering the house, 
 is heated by passing between flat tubes of iron 
 rilled with hot water. From the place of these in 
 a vault below, it spreads under the floor, and enters 
 the house through a vast number of small open- 
 ings in the floor. The air departing from the house 
 first reaches a space over the ceiling, through 
 suitable passages, and then, by the action of the 
 chimney, is drawn away along a lobby or passage
 
 VENTILATING. 
 
 87 
 
 to feed the great fire at the bottom of the chimney. 
 The force of the action was estimated in Art. 80, 
 and it is such as to carry away in a few minutes 
 any smoke or smell, as of gunpowder inflamed, or 
 ether spilt, from the body of the house. Besides 
 the heavy original expense of the arrangement, 
 there is the defect, which could easily be cor- 
 rected, of the entering air being caused to pass 
 through the floor, and therefore also through the 
 matting upon the floor, which being loaded often 
 with dust from the feet of the members, on any 
 considerable motion of their feet, as on the occa- 
 sion of a division of the house, sends a cloud of 
 the dust upwards, to their great annoyance. The 
 air might enter as well by openings above the 
 floor. 
 
 108. In accordance with the views of the sub- 
 ject taken above, the House of Commons might be 
 warmed by air coming from the present hot-water 
 
 J/f^l 
 
 apparatus, or from a sufficient surface extent of 
 thermometer-stove in the same place, to enter 
 by many openings near, but above the floor, and 
 to be drawn through the house and ceiling by the 
 action of one or more great ventilating-pumps
 
 88 WARMING AND 
 
 worked by a power of one horse or less, in lieu of 
 the very wasteful chimney. And the House being 
 once warmed, would be kept warm, as well as 
 full of pure air, by the double-current apparatus 
 worked in proportion to the number of persons 
 present. Supposing a b c d to represent any great 
 room or hall, through holes in the ceiling of which 
 a by the hot polluted air from the lungs and 
 lamps of an assembly below, might enter a space 
 leading by the tubes b e pf to the pumpg-. If then 
 h were another pump forcing pure air in a contrary 
 direction, or inwards along the larger tube q p I d 
 surrounding the smaller tubes, and taking their 
 heat from them, there would be the complete 
 double-current apparatus before spoken of. At 
 k i might be placed the stove, close to which 
 the entering air might pass to be warmed if 
 required. There is perfect ventilation under an 
 open arch, when the wind blows through it how- 
 ever gently ; and the ventilation would continue, 
 if a crowd of persons were there, seated with their 
 backs to the wind, on open platforms raised like 
 the seats in the House of Commons. Now all the 
 sides of the House of Commons might be thus 
 perfectly ventilated at the same time by air ad- 
 mitted freely from around, towards suitable cen- 
 tral outlets. 
 
 Theatres. 
 
 109. These might be moderately warmed by 
 thermometer-stoves with surface much extended 
 by wings or flues, placed in various situations, and
 
 VENTILATING. 89 
 
 acting for some time before the opening of the 
 doors. Afterwards, during the performance, the 
 double-current apparatus should be in constant 
 action. Because the different tiers of boxes form 
 each a partial roof detaining hot impure air in its 
 hollow or upper part, there should be one or more 
 ventilating openings from each tier communicating 
 with the great pump. Fresh air should be admitted 
 at numerous points. 
 
 Hospitals and Poor -Houses. 
 110. The importance of pure and warm air to 
 our unhappy brethren who become the inmates of 
 hospitals, need not be dwelt upon. Wards may be 
 well warmed, according to their size, by one or 
 two thermometer-stoves in each, and may then be 
 fairly ventilated by suitable simple ventilating holes 
 near the ceiling. A small double-current apparatus 
 might, at little expense, be placed in each ward. 
 One grand system of double-current ventilating 
 and warming might be adopted for the whole 
 house. There would be advantages, however, in 
 having stoves in the separate wards. To the unoc- 
 cupied invalid hospital inmates, the self-regulating 
 fire would be a pleasing companion. In any case 
 of a room, containing a few inmates, where only 
 as much air needs to enter as is required to 
 ventilate the room, even if that air enter without 
 being heated, it will not produce a dangerous 
 draught. Many hundreds of pounds have been 
 expended, in single hospitals in London, on abor- 
 tive schemes for warming and ventilating.
 
 90 WARMING AND 
 
 Uniform climate for Invalids. 
 
 111. At the present day many invalids are sent 
 from England to winter in the south of Europe or 
 in Madeira, away from beloved friends and home, 
 and deprived of their accustomed comforts, because 
 their own country has not offered them safe pro- 
 tection from the weather. Now by uniting the 
 agency of a thermometer-stove always alight, 
 complete ventilation by single or double current, 
 proper diffusion of moisture in the air, double 
 windows, and the use of the air-warming mouth- 
 piece described in Art. 84, the most desirable 
 state of atmosphere through both the day and the 
 night, in the house and out of doors, is easily 
 attainable. A slight difference in temperature 
 between day and night seems not undesirable, 
 even for invalids, as it occurs naturally all over 
 the world, owing to the appearance and disap- 
 pearance of the sun. 
 
 Cotton Mills and other Factories. 
 
 112. These are now conveniently warmed by 
 pipes, receiving steam from the engine-boilers, 
 chiefly at meal times, when the engines are not at 
 work. There being boilers to form the steam, and 
 engineers to manage it always present, and en- 
 gines with spare power to drive fan-wheels for 
 ventilation with any velocity, the purposes are 
 effected at little cost. The substitution of venti- 
 lating pumps for the fan-wheels would be a 
 material improvement.
 
 VENTILATING. 91 
 
 Hot-houses and Conservatories. 
 
 113. Thermometer-stoves, with extended wings 
 or flues, as described in the section on " Manu- 
 facturing," would answer well ; or hot-water 
 apparatus with one of the new heat- regulators, 
 or the common brick flues, made thinner towards 
 the chimney, with a heat-regulator for the fire. 
 
 Zoological Gardens. 
 
 114. The destruction among the tropical ani- 
 mals kept in the London Zoological Gardens, from 
 insufficient and fluctuating warmth and impure 
 air, has been lamentable. The stove and ventila- 
 tion above-described would remedy the evils in 
 respect to the animals of warm climates, and the 
 cooling apparatus in summer would benefit the 
 others. 
 
 Ventilation of Mines, and Prevention of Explosions 
 in them. 
 
 115. In many coal-mines there is a copious dis- 
 engagement of carburetted hydrogen gas or fire- 
 damp, which mixes with the common air, and on 
 being inflamed by a miner's lamp, explodes with 
 such violence as to destroy in an instant the lives 
 of all the persons who may be working in the 
 neighbouring galleries. Security against this acci- 
 dent is sought by ventilating the mines, and by 
 the use of what have been called safety-lamps. 
 The ventilation is effected either by converting 
 one shaft of the mine into a chimney, as described 
 at Art. 80 ; or by directly pumping a large quan-
 
 92 WARMING AXD 
 
 tity of atmospheric air into the mine. The safety- 
 lights are of various kinds. The best known is 
 that of Sir Humphrey Davy. 
 
 Davy, having in the course of his admirable 
 researches into the nature of combustion, disco- 
 vered, that a cloth or gauze made of fine wire, 
 obstructed the passage of flame, proposed forming 
 a lantern of such gauze, and placing a lamp in it, 
 which might then be introduced without explosion, 
 into the most inflamable mixtures of hydrogen gas; 
 and, therefore, into \hzjire-damp of mines. This 
 lamp, since known as Davy's Safety-Lamp, has 
 enabled proprietors to resume the working of many 
 mines ; which, owing to the frequent explosions of 
 fire-damp in them, with great loss of life, had been 
 abandoned. Unhappily, however, even this beauti- 
 ful contrivance has not proved a complete security, 
 for whether, as some have asserted, because the 
 flame traverses the gauze, in the case of a sudden 
 rush of gas upon it, from what is called in the 
 mine a blower ; or, because the workmen are 
 negligent as to shutting the lamp, and keeping it 
 in repair : in the present extended working of 
 coal mines, destructive accidents are again very 
 frequent. There is, moreover, in the Davy lamp, 
 the disadvantage that the gauze around the flame 
 intercepts a great part of the light. Within a few 
 years various modifications of the wire-gauze 
 security have been proposed, but no one is free 
 from objections. 
 
 Having had my attention drawn to this subject, 
 as part of the general subject of ventilating ami 
 warming, I became convinced that perfect security
 
 VEXTILATIXO. .93 
 
 against explosion in mines was obtainable, and 
 in a very simple way, but from a principle entirely 
 different from what has directed previous attempts. 
 This way is to supply the lamps or candles in the 
 mine with air for combustion, not from the mine 
 itself as hitherto, but through pipes from the 
 atmosphere above, as coal-gas is supplied through 
 pipes to common street lamps. 
 
 At the mouth of most mines there is a steam- 
 engine at work, part of the office of which, is to 
 pump air into the mine for ventilation. Now a 
 very small portion of this air, if sent unmixed to 
 the lamps by pipes, would give the security 
 desired. These pipes might be of very cheap 
 material and construction, as of common plank 
 for instance, with the seams pitched, nailed along 
 the cuttings of the mine. At the top or com- 
 mencement of the main pipe, there would be a 
 small gas holder of the usual construction, to 
 receive air from the pump, and which would be 
 nicely balanced, that the propelling pressure 
 might be uniform and accurately determined. 
 That pressure would then be transmitted along 
 the tube, so that at any crevice or opening there 
 would be a steady outward rush of pure atmos- 
 pheric air, as there is a jet of coal gas from 
 any opening in common gas apparatus. A com- 
 mon lantern, therefore, screwed on, or otherwise 
 attached at such opening, would be supplied with 
 pure atmospheric air ; and if there were no open- 
 ings in the lantern but the receiving opening, and 
 a chimney of fit size, defended by a certain length 
 of tube, and even by a valve or wire-gauze, if
 
 94 WARMING AND 
 
 desired, there could be no communication between 
 the flame and the air of the mine 
 
 With such an apparatus for fixed lights, and 
 which might be of any intensity, it would be 
 necessary merely to screw on lanterns to the air- 
 pipe, in desired situations. 
 
 For lights moveable to a certain distance, there 
 would be lanterns connected with the air-pipe, 
 by flexible tubes of covered spiral wire. 
 
 For lights portable to any distance, there would 
 be other lanterns, large enough to hold as much 
 air as would feed the flame for half-an-hour or 
 more, before it became too dim or small ; or lan- 
 terns, having attached to them bags of oiled silk, 
 or other fit material, to be filled from time to 
 time, with pure air from openings in the air-pipe; 
 or lanterns fed with air from strong metallic 
 vessels into which it would be condensed, as coal- 
 gas has been condensed into similar receptacles. 
 
 All along the main air-pipe there would be 
 means of fixing lanterns, and of taking out pure 
 air for any purpose. 
 
 There might be at convenient stations in the 
 mine, boxes or small chambers communicating 
 with the air-pipe, and therefore, always full of 
 pure air, in which the operations of striking a 
 light, lighting lamps, cooking even, &c., might 
 be performed. 
 
 To light lamps or candles where wanted in the 
 mine, a long lucifer match passed through an 
 opening in the side of the lantern, and inflamed 
 within it, by undergoing suitable friction might be 
 used.
 
 VENTILATING. 95 
 
 Ventilation of Tunnels in Railways. 
 
 116. This takes place in all cases, at present: 
 1. By the wind blowing through them. 2. By 
 the effect of the perpendicular openings in them 
 called shafts, through which the air in winter, 
 because then hotter than the atmosphere, ascends; 
 in summer, because colder descends ; producing, 
 in both cases a change of the mass below. 3. By 
 the passage through the tunnel of the trains of 
 carriages driving the air along. 
 
 In any case where these influences are in- 
 sufficient, it would be easy, by hoisting a sail on 
 one of the carriages of a train, as described at 
 Art. 78, which sail would nearly stretch across 
 or fill the tunnel, absolutely to sweep out the 
 whole of the air at each transit. 
 
 Seeing, thus, how certainly the ventilation of 
 tunnels may be effected, it may be well, here, to 
 notice the objections made in the year 1836, 
 before Committees of the House of Commons, by 
 men of reputation, to tunnels in railways, alto- 
 gether, as dangerous to the health of passengers, 
 and chiefly on account of the asserted difficulty of 
 ventilation. Were such prejudices to remain un- 
 exposed, they might prove obstructive of the 
 extension of the new and almost miraculous means 
 which the railway offers, of forwarding human 
 civilization and happiness. 
 
 These parties thought they saw six great 
 dangers to health in the tunnels : namely, 
 
 1. The Temperature. Yet this in tunnels is 
 always the medium temperature of the climate,
 
 96 WARMING AXU 
 
 equally removed from the two hurtful extremes of 
 heat and cold, and differs little from the natural 
 atmospheric temperature of a great majority of 
 days in the year. And in the warmest summer 
 noon, a person entering a tunnel for the usual 
 minute or two of the passage, is less tried, than a 
 person in winter crossing a staircase, from one 
 warmed room to another ; and much less, than 
 one who follows the almost universal practice 
 of going to bed in a room without a fire. 
 
 2. Impurity of Air from Smoke. Yet, the thing 
 objected to, exists of the same kind, and often 
 more in degree, in a smoky room anywhere. 
 
 3. Moisture from the Condensed Steam and the 
 Springs in the Earth. Although there is much 
 less of it than in the air of a misty or rainy day. 
 
 4. Rapid Passage through the Air. Although 
 the effect is the same, as of the wind passing 
 persons in a windy day; and much less than 
 when in the open air the railway carriage moves 
 against the wind. 
 
 5. Sudden Darkness. Although the change is 
 less sudden, than when a person puts his hands 
 over his eyes, or goes into a dark cellar, or when 
 the lights in a room are suddenly extinguished. 
 
 6. Noise. Although this is not so great as in 
 many manufactories, or of military review firing. 
 
 And be it remarked, that, a man who chooses 
 to pull up the glasses of the carriage, and carry 
 the same air with him through the tunnel, abso- 
 lutely avoids four of the alleged dangers, namely ; 
 the change in temperature, in purity of air, as 
 to smoke and moisture and the current ; and bv
 
 VEXTILATIXG. 97 
 
 shutting his eyes and putting cotton in his ears, 
 he may if he choose avoid the other two. 
 
 The whole six objections fall properly under the 
 head of Alarm from Novelty to a person ignorant 
 or inexperienced. And, as a child allowed to 
 believe in ghosts, may be terrified into fits by any 
 noise in a churchyard at night ; so may grown-up 
 children, so ignorant or thoughtless as not to be 
 aware, that the human constitution can bear with 
 impunity much greater changes as to tempera- 
 ture, composition of the air from smoke and 
 moisture, currents or winds, light and darkness, 
 and noise, than he meets in a tunnel be terrified, 
 and, as far as the terror can hurt, be hurt, by 
 passing through a tunnel. The effect, on any 
 ordinary person, is in reality the same as of passing 
 along any narrow street at night. 
 
 REMARKS 
 
 ON MANUFACTURING, FIXING, AND USING THE 
 THERMOMETER-STOVE. 
 
 117. Intelligent manufacturers, on comprehend- 
 ing the principle of this stove, will immediately 
 see that it admits of endless variety of form and 
 arrangement, and will know better than I can be 
 supposed capable of telling them, how best prac- 
 tically to mould their material for the purposes 
 sought. I wish, therefore, the following remarks 
 to be considered rather as suggestions or exempli- 
 fications, than as precise directions. Iron will be 
 H
 
 1)8 REMARKS ON MANUFACTURING 
 
 the fittest material, but a useful stove may be 
 formed of earthenware. 
 
 118. This stove consists, in its common form, of 
 
 the outer metallic case or body, A B C D, en- 
 closing the fire -pot or grate E, with its ash-pit, the 
 light screen f surrounding the fire-pot, the dome 
 k and funnel p placed, when wanted, over the fire, 
 to carry the hot smoke directly into the chimney, 
 and the thermometer-regulator g, of one of the 
 forms to be described below. The openings in 
 the stove are, the door h, the smaller ash-pit door 
 below, the chimney-flue, and the opening for the 
 thermometer. 
 
 1 . Manufacturing. 
 
 119. The body, A B C D, may be of any shape, 
 as of a box, pedestal, vase, urn, pillar, cylinder, &c. 
 or even of a statue. Convenient dimensions for an 
 ordinary sitting-room, are, for the top and bottom, 
 about 20 inches square ; for the height, about 30 
 inches. The body may be of one sheet of plate
 
 THE THERMOMETER-STOVE. 99 
 
 iron, bent into the form, with the openings cut in 
 it ; or it may have the front of cast iron orna- 
 mented, and the back and sides of the bent plate ; 
 or the whole body may be of cast iron. 
 
 120. The top and bottom, A B and C D, may be 
 cast-iron plates with grooves in them, to receive 
 the upper and lower edges of the body, the 
 grooves being filled up and made air-tight as in 
 the common American stove, by plaster of Paris, 
 or good mortar. The groove in the bottom may, 
 if desired, be filled with sand, to facilitate the 
 opening of the stove for any purpose ; or the sand 
 joint may be made at the top, by letting the inner 
 wall of the groove dip into a channel of sand formed 
 around, and within the upper edge of the body. 
 
 121. The fire-pot or grate, E, and ash-pit. The 
 fire-pot may be square or round, and for the size 
 of stove described above, may have about 10 inches 
 internal width, and 10 or 12 of depth. It is lined 
 with fire-brick to the thickness of about 2 inches, 
 which fire-brick, being a bad conductor of heat, 
 preserves the fuel in an ignited state, even after 
 the combustion has been for some time suspended, 
 and so prevents the fire from being readily extin- 
 guished. The grate should have one or two of its 
 bars removable, so that any pieces of stone or 
 clinker which happen to accumulate in it, may 
 be withdrawn without interrupting the combus- 
 tion. To secure in part the all-important object of 
 preventing any air from reaching the fire but what 
 enters by the destined air passage, the ash-pit 
 should form one piece with the outer case of the 
 fire-pot, either having been cast as part of it, or, 
 
 H 2
 
 100 REMARKS OX MANUFACTURING 
 
 being made of sheet iron, with seams close enough 
 to hold water. Any defect in this respect, would, 
 when the ash-pit were quite closed externally, 
 allow the air or the smoke from the body of the 
 stove to enter the ash-pit and to reach the fire so 
 as possibly, if altogether smoke, to extinguish it, or 
 if chiefly pure air admitted by the stove- door 
 above, to make it burn too rapidly. A very free 
 communication purposely left between the ash-pit 
 and stove, allows the air from the ash-pit to reach 
 the chimney without passing through the fire, and 
 changes the action of the stove in an important 
 way, as will be described below. 
 
 122. The stove door, h, should not be much larger 
 than to admit readily the deep narrow shovel 
 convenient for feeding the fire. The reasons are, 
 that it may more easily be made close, and that 
 when it is opened to admit fuel, there may be less 
 chance of any of the hot air or smoke escaping to 
 the room. The hinges may be on the outside or 
 inside, and the catch may be of various kinds. 
 A good door is a flat plate, ground true against 
 the projecting rim of the door, and in lieu of 
 hinges, having a single nail at its side, on which 
 it turns like the common cover of a key hole. For 
 the purpose of increasing occasionally the draught 
 of the chimney, as will be explained below, there 
 should be either means of retaining the stove- door 
 slightly open in various degrees, or there should 
 be a small opening in the door, with a turning 
 plate in it, to be more or less closed, as wanted. 
 
 123. The ash-pit door may be made like the last 
 described, and large enough to allow the easy
 
 THE THERMOMETER-STOVE. 101 
 
 removal of the ashes. It must fit perfectly, or the 
 stove will not be under command. 
 
 124. The chimney-flue should issue from the stove 
 near the top, to ensure ready passage of the smoke 
 into the chimney. As all the fresh air required to 
 feed the fire, may enter by an opening which would 
 admit a finger, and of course no greater quantity 
 of air will leave the stove by the chimney, the 
 glass of an Argand lamp is really big enough to 
 carry away the smoke or gases. But to obtain, 
 when the stove-door is opened, an in-draught so 
 powerful, that none of the hot air shall escape by 
 the door into the room (as hot air from a room 
 escapes into a cold passage by the top of an 
 opened door, while cold air is entering below), 
 there must be a chimney flue of from three to four 
 inches in diameter. 
 
 125. The screen, ff, around the jire-pot. The use 
 of this, as of the partition in the stove represented 
 at page 43, is to ensure in the box circulation of 
 the air, and thereby uniform temperature every 
 where. The fire-pot itself becomes hot externally, 
 notwithstanding the brick lining, and the air in- 
 cluded between it and the screen becoming hot in 
 consequence, rises constantly, and is replaced by 
 the coldest air in the stove through a space left 
 between the bottom of the screen and the bottom 
 of the stove, and thus a constant circulation is 
 maintained. Again, if the exterior of the fire-pot 
 were to become very hot, and had no screen, it 
 would radiate its heat so directly to the sides of 
 the stove near it, as to overheat them, and for 
 this reason also, the screen is occasionally useful.
 
 102 REMARKS ON MANUFACTURING 
 
 A screen such as here surrounds the fire-pot, may 
 be placed externally around the lower part of the 
 stove itself, to ensure perfect circulation of the 
 air in the room, and thereby the desired warmth 
 of the floor. 
 
 126. ~The dome cover, k, when placed on the fire- 
 pot, completely protects the surface of the fire 
 from the approach of atmospheric air, and thus 
 certainly prevents the accident of the large flame, 
 or semi-explosion which might happen, if wood or 
 bituminous coal were incautiously allowed to distil 
 inflammable gas into the body of the stove, and 
 then atmospheric air were allowed, by opening 
 the stove-door, or otherwise, to mingle with the 
 gas in contact with the burning fuel. 
 
 127. The hot air funnel, p. In weather not very 
 cold, or in countries where it might be desired to 
 add only one or two degrees of heat to the air of a 
 room, chiefly to destroy moisture, if by the screw 
 of the regulator, the fire were slackened to the 
 lowest degree, there would be danger of extin- 
 guishing it, or of not sending heat enough into the 
 chimney to produce a draught: but by this funnel, 
 the warm air from even a considerable fire may be 
 sent into the chimney, without being allowed to 
 circulate in the stove- case, and thus all the de- 
 sired objects are secured. 
 
 128. Another mode of sending more heat into 
 the chimney for the purpose above stated, or to 
 make an ill-drawing chimney act, is, to open the 
 stove-door a little, as described in Art. 122, so 
 that cold air may be constantly entering the stove, 
 and displacing hot air towards the chimney ; or to
 
 THE THERMOMETLLR-STOVE. 103 
 
 have a small, ventilating opening in the door of 
 the stove, to be more or less shut at will, by a 
 turning plate or shutter. This is a mode of heating 
 the chimney more expensive than the funnel, by 
 reason of the greater quantity of hot air which 
 escapes, but the necessary expense of fuel with 
 this stove is in any case so trifling a consideration, 
 that the mode here described may often be pre- 
 ferred. It may be combined with the funnel. 
 
 129. In contemplating the action of a chimney, 
 we must recollect, that the carbonic acid pro~ 
 duced by combustion, is heavier than common air, 
 and, if in a chimney it became as cold as com- 
 mon air, would therefore descend. Now if the 
 saving of heat be carried too far in the thermo- 
 meter-stove, the air in its chimney at a certain 
 distance up, may be so cold, as to be heavier than 
 common air, and then, instead of aiding, will 
 obstruct the ascent of the hotter air below it. A 
 chimney built expressly for the stove, and there- 
 fore of small diameter, would waste very little heat, 
 but the large old chimneys often cause a great 
 waste of fuel. 
 
 130. The only fire-iron absolutely required for 
 the stove is the bent piece of strong iron wire fixed 
 in a handle, and called the rake, or poker, used for 
 clearing the fire bars below. It will be convenient, 
 however, to have a small shovel, made expressly for 
 putting on the coal, and a pair of long pincers, or 
 light tongs, for lifting or arranging pieces of the 
 burning coal. For a well managed stove, a bellows 
 to blow the fire can never be wanted; but any 
 common bellows may be fitted to the stove by
 
 104 REMARKS ON MANUFACTURING 
 
 putting around its nozzle a plug which fits one 
 of the apertures into the ash-pit. 
 
 131. Thermometer Regulators. This term point* 
 to the most important part of the new stove, or that 
 on which most of its valuable qualities depend. 
 Because the term explains itself at once to popular 
 apprehension, it is preferred here topyrostat, which 
 would be a single Greek word having nearly the 
 same meaning, but suggesting a clear idea only to 
 persons who know Greek. A great object sought 
 in the construction of the stove was, that when the 
 stove reached any desired degree of temperature, 
 there should be, in or about it, a thermometer 
 capable not only of indicating the degree of tem- 
 perature reached, but also of doing the work of 
 moving a valve to check the admission of air, 
 whenever the heat were at all above the degree 
 desired, and of increasing the admission when the 
 heat fell below that degree. 
 
 Of such working thermometers, or heat-go- 
 vernors, while I was seeking the fittest, a great 
 variety presented themselves to my mind, of which 
 I shall here describe enough to give makers an 
 abundant choice. With the one exception of the 
 pendulum, they all depend on the general law of 
 nature, that heat expands substances. 
 
 132. I. The first which I shall describe is that 
 familiar to the public under several other forms 
 namely, Arnold's beautiful contrivance of the com- 
 pound metallic bar, which, as described in my "Ele- 
 ments of Physics," he introduced into the balance- 
 wheel of his chronometers ; and which has since
 
 THE THF.RMOMETER-STOVE. 105 
 
 been used, as a simple thermometer, by Crichton, 
 of Glasgow, twenty years ago, and by Breguet, of 
 Paris, in a thermometer of another form. I caused 
 a piece of thin iron hoop or plate, two feet long, 
 by about one inch broad and a sixteenth thick, to 
 be rivetted to a similar piece of brass plate, so as 
 to form with it a compound plate straight when 
 of common temperature, but which, when heated, 
 was bent considerably as damp paper is bent 
 or curls when held before the fire. In such 
 rod, the brass, expanding more than the steel, 
 becomes in a degree, like a bow, of which the 
 iron is the bow-string. Such a bar, A B, if 
 firmly fixed at the top, A, hangs 
 straight down, when cold, in the 
 position A B, but, if heated, bends 
 so as to have its lower extremity 
 at C instead of B ; and, if it be 
 placed in a stove of which the air- 
 entrance is near B, it will, by 
 bending, draw the projecting arm 
 of wire, B D, inwards; and the 
 plate D, screwed on the end of the wire, will be 
 brought close to, and will shut the opening at B. 
 Evidently, by screwing the plate nearer to or 
 farther from the stove, the air-passage will be 
 closed sooner or later ; and thus the temperature 
 of the stove may be permanently fixed at any 
 desired degree. 
 
 133. This kind of regulator would be formed and 
 placed variously, according to the construction of 
 the stove. It is very simple, and would answer 
 well where care were bestowed ; but, if it be once
 
 106 REMARKS ON MANUFACTURING 
 
 much overheated, it takes what is called a " set," 
 and does not on cooling return quite to its previous 
 state. 
 
 134. Although this compound bar, besides being 
 used in the ways above described, had been ap- 
 plied also some years ago to regulate the heat of 
 a baker's oven, an eminent chemist here, sub- 
 sequently took a patent for it, and not only as 
 applied to a purpose he then had in view, of regu- 
 lating the heat of a sugar-boiling pan, but in all 
 other applications of it, as a heat-regulator, which 
 future inventors might devise. If the bar, however, 
 had been the only or the best regulator of a stove, 
 which it is not, we can hardly suppose that the 
 law would have allowed a person who had no 
 share in the meritorious original invention of it, 
 or in the subsequent applications of it as a ther- 
 mometer, or in first thinking of a heat-regulator, 
 or in applying the bar as such, to call it his 
 own, to the extent of levying a tax on the public 
 for using it, which tax, at five shillings each for 
 every house in London alone, would amount to 
 50,000. 
 
 135. The next principle which I shall describe, 
 as capable of furnishing a thermometer-regulator, 
 is the expansion of air by heat. It is a fact 
 ascertained, that by adding 4-80 degrees of heat to 
 any quantity of air, the volume of the air is thereby 
 doubled, the effect being in the same proportion 
 for any other change of temperature. By en- 
 closing a quantity of air, therefore, in any tube 
 or vessel placed within the stove, and causing its 
 gradual expansion by the heat to give motion
 
 THE THERMOMETER-STOVE. 
 
 107 
 
 to something, which, at any desired degree of 
 temperature, shall shut a valve in the passage 
 by which air enters to feed the combustion, 
 which valve shall open again the instant the tem- 
 perature falls, the object will be accomplished ; 
 and this is done by any of the forms about to be 
 described. 
 
 136. The annexed figure represents a glass tube, 
 
 u 
 
 (of which the middle portion is not shown here for 
 want of room,) straight from A, where it is closed, 
 to B, where it takes a bent or horse-shoe form, 
 ending with an open mouth at D. Mercury, put 
 into the bent part, between B and C, shuts up the 
 air in the body of the tube, and, as that air is 
 heated and expanded, the mercury is depressed 
 in the part B, to rise equally in the leg C, and a 
 float of wood or glass, on the mercury at C, rises 
 at the same time with force sufficient to move a 
 valve in some one of the numerous ways to be
 
 108 REMARKS OX _M A X UF ACTU RING 
 
 described below. Here the float has a spindle 
 rising from it to H, steadied by passing through a 
 fixed support at H, or through a hole in the cap 
 or cover of the tube, and the spindle has a screw- 
 button on it above D, on which the valve-plate F 
 rests by means of the wire D C G F, and, accord- 
 ing to the height of the button, the valve is shut 
 at a high or low temperature, being lifted by 
 its rising to close the tube E. The float may be 
 made of wood, and it should have little studs or 
 ribs of wire around it, projecting from its sur- 
 face sufficiently to prevent its being any where 
 so near the glass as to expel the mercury from 
 between them, and then to suffer friction. If the 
 tube, from A to the surface of the mercury in B, be 
 twelve inches long, an increase of heat in the stove 
 of 180, or the difference between freezing and 
 boiling water, would expand the air, if remaining 
 under the same pressure, about four inches, 
 according to the law, explained above, that 480 
 double the volume of air ; but, as the mercury in 
 the tube C, in rising above the mercury in B, 
 becomes a column compressing the air, while the 
 lately high column in B, which, by resisting the 
 atmospheric pressure, was expanding the air, 
 exists no more, the confined air, instead of acquir- 
 ing an additional bulk of four inches, will have its 
 expansion restrained, according to circumstances, 
 to about two. This range of motion for the mercury, 
 of about two inches between the points of freezing 
 and boiling water, is necessary to enable the regu- 
 lator to shut the valve at a point sufficiently exact.
 
 THE THERMOMETER-STOVE. 109 
 
 Such a tube, then, as now described, of from half 
 an inch to five-eighths of an inch in diameter, 
 with its straight part B A within the stove, forms 
 an excellent regulator, as easily placed or taken 
 away, or renewed in case of accident, as the glass of 
 an Argand lamp, and which has the great advan- 
 tage that the fluctuating mercurial surface is visible 
 just as in a barometer, declaring, therefore, at any 
 moment, the state of the fire. If there be about 
 three inches of mercury in the tube, so introduced 
 by the means described below, as to be nearly all 
 in the leg B when the instrument is cold, it will 
 descend, on being heated as above described, to 
 rise in the leg C. If the heating be carried too far, 
 as if the valve do not close properly, not only will 
 all the mercury be pushed into the leg C, but 
 bubbles of the confined air will be forced through 
 it, and the adjustment of the instrument will, for 
 the time, be disturbed. When the instrument cools 
 again, however, the mercury will first all return 
 into the leg B, and then bubbles of air will follow 
 through it, to restore the adjustment. Thus the 
 length of tube and quantity of mercury being 
 rightly proportioned to each other, the instrument 
 will readily rectify itself after any disturbance : at 
 some degree above boiling heat, air will be blown 
 out, and at a low heat, any air wanted will again 
 be blown in. But, without waiting for the cooling 
 of the stove, the adjustment may at any time be 
 restored, by 1st, withdrawing the hot tube; 2dly, 
 letting all the mercury run down to the end A ; 
 3dly, letting it run gradually back to its place in
 
 110 REMARKS ON MANUFACTURING 
 
 the bend under C ; and 4thly, cautiously plunging 
 the tube into cold water, to cause air to blow in. 
 The original adjustment is made as now described, 
 only the tube is heated by being put into hot 
 water. The tube of the thermometer may be of iron, 
 as well as of glass, but then the height of the 
 mercury cannot be seen. 
 
 137. The valve part itself which shuts the air- 
 passage, may be of various forms. A round plate F, 
 lifted up against the mouth of the air-tube E, 
 of about two inches wide, is one form, the 
 chief weight of the plate and its wire being sup- 
 ported by a fine spiral spring at G. Such a valve 
 may also be placed at once on the float-spindle 
 at H, to rise against an air-tube's mouth placed 
 above it. Again, the valve may be what is called 
 a throttle-valve, namely, a plate as a b hung on 
 an axis in the mouth of the air-tube 
 ff; so that, when its edge is turned 
 to the current, it offers little obstruc- 
 tion, but when its side is turned, it 
 entirely closes the passage. The wire 
 e d, descending from the regulator D in last figure, 
 by pulling at the short lever d, shuts the valve. In 
 this form a small ball or knob of metal, c, on a 
 screw, is fixed to the back of the throttle-valve, 
 to enable persons, by screwing the ball nearer or 
 farther from the axis, to balance the weight of 
 wire, &c. on the other side. If the valve be not 
 nearly balanced by this knob, the mercury has 
 too much to do, and there may be too much 
 friction.
 
 THE THERMOMETER-STOVE. 
 
 Ill 
 
 138. This figure exhibits another 
 arrangement, in which the float A 
 is, by means of a lever, balanced 
 3 A against the valve plate C, and, when 
 lifted by the rising mercury in the 
 horse-shoe tube lets the valve fall 
 and close. 
 
 139. This cut exhibits, perhaps, the simplest 
 
 form of the expanding air regulator ; a b c is a 
 bent glass tube, closed at a, and open where it is 
 cup-shaped at c. The bottom part, b c, has mer- 
 cury in it. The part a b is placed within the stove. 
 Over the cup c, and dipping into it, is the mouth 
 of the tube, which admits air to the stove. When 
 the stove is heated, the expanding air in a b 
 depresses the mercury in b, to raise it in c, until 
 it approaches or reaches the mouth of the air tube, 
 and so arrests the entrance of air. In this form 
 there is no moving part or friction, but in the 
 rising fluid, the surface of which is in fact, the 
 valve-plate or stopper, and it cannot fail to act.
 
 112 REMARKS ON MANUFACTURING 
 
 Common oil would serve in it nearly as mercury, 
 rendering the apparatus very cheap. To enable 
 persons by this regulator to fix the heat of the 
 stove at any desired degree, the mouth of the air- 
 tube c is made to slide or screw up and down, so 
 as to be approached by the fluid at a higher or 
 lower degree of heat. 
 
 140. This is merely another arrange- 
 ment of the parts shown in the last. It con- 
 sists of an outer cup with a wide mouth, 
 of an inner cup inverted and fixed in the 
 other, but allowing passage of mercury 
 or oil between them ; of the small tube A 
 coming from a vessel of air in the stove, 
 = and reaching to near the top of the inner 
 cup, and lastly, of the air tube D, gaping into the 
 exterior cup. Heating the stove then causes air to 
 enter the inner vessel, and to drive the mercury 
 contained in it out at its bottom, so as to rise in 
 the outer vessel, and when the mercury reaches 
 the wide part above, it touches and so shuts the 
 mouth of the tube D, which carries air to the fire. 
 
 141 . All the regulators of the expanding- air kind 
 as yet described, are also thermometers visible ex- 
 ternally, and whatever may go wrong in them, is 
 therefore evident, and can easily be remedied. 
 This is a quality of such importance, that no judi- 
 cious person will use a concealed regulator. To see 
 the mercury is in effect to see the fire, for the 
 slightest change towards increase or diminution of 
 activity is indicated at once, just as changes of 
 atmospherical state are shown by the barometer 
 in the bulging and brilliancy or in the sinking and
 
 THE THERMOMETER-STOVE. 
 
 113 
 
 fadingof the top of the mercurial column. There are 
 other forms of thermometer which have the disad- 
 vantage of being more or less concealed, for example: 
 142. Two bulbs, or globes 
 of glass A and B, are blown 
 at the ends of a small tube, 
 which is supported, and turns 
 like a balance on its centre. 
 One of the bulbs A, which is 
 close, has air and mercury in 
 it, and when it is heated, the air expanding pushes 
 the mercury into the other bulb which is open at 
 the top, and causes that bulb to preponderate with 
 force sufficient to move a valve. The valve may 
 be any of those described above, as the plate E 
 suspended over the air passage D. A sliding 
 weight G, on one arm of the glass, enables persons 
 to fix the preponderance at different degrees of 
 heat. A small weight C, projecting below from 
 the middle of the tube, keeps the centre of gravity 
 below the point of suspension, and compensates 
 for a certain degree of motion of the mercury to- 
 wards B, at the instant of the balance turning. In 
 this form the axis may project outwards, through 
 the front of the stove, and carry a hand, or index, 
 from which the wire which works the valve may 
 descend. 
 
 143. This is another form 
 of the last described mo- 
 dification, which allows the 
 mercury to be seen; the 
 part B E being outside of 
 the stove, and parallel to 
 i
 
 114 REMARKS ON MANUFACTURING 
 
 its surface. The tube at E is bent, not only as here 
 seen in profile, but also across, so that about an 
 inch of it at E forms the axis of motion of the 
 whole. Much motion is not to be allowed in either 
 this, or the preceding form. 
 
 144. This represents a tube, 
 formed into a wheel or circle, 
 turning on its axis C, the end 
 D of the tube being closed, 
 the end E being open, with a 
 quantity of mercury B A in the 
 middle, shutting up air in B D. 
 In this form, as in the last two, the expansion of 
 inclosed air, by driving mercury from one side B 
 of the point of suspension, to the opposite A, 
 causes the side A to preponderate, and to turn the 
 hand or index, which, as in the last two forms, works 
 any valve. This form, contrary to my expressed wish, 
 has been extensively used, and many failures have 
 hence arisen. The causes have been chiefly that it 
 was not readily understood by ordinary persons, 
 and being of delicate adjustment, was often ill- 
 made : there was imperfect balancing on its axis ; 
 unsuitable quantity of mercury; blowing out or 
 evaporation of the mercury from over-heating; 
 too much friction ; necessity of opening the body 
 of the stove to fix it ; greater price, &c. All the 
 three kindred forms last described, when properly 
 proportioned, rectify of themselves any accidental 
 derangement, by blowing out and blowing in air, 
 as described in article 135. In a circle of this kind, 
 of uniform bore, mercury resting in the middle 
 when cold, would cause about a ninth of a revolu-
 
 THE THERMOMETER-STOVE. 115 
 
 tion, while the machine were being warmed from 
 freezing to boiling. To have greater range, the 
 mercury must be placed nearer the end E, or the 
 closed end of the tube must be made wider to 
 contain more air, or the tube must be formed into 
 two smaller turns or circles, instead of one large 
 circle. The best mode of using this form, would 
 be to let the axis come out through the side of the 
 stove, to exhibit by the motion of an index upon 
 it, the progress of heating, and by that index, or 
 something attached to it, to shut the valve at any 
 desired degree. 
 
 With respect to all the kinds of air-thermometer, 
 it is to be observed, that the changing pressure of 
 the atmosphere indicated by the barometer, influ- 
 ences them a little ; but as the effect on the heat 
 of the room can never amount to a change of one 
 degree, the fact is quite unimportant. 
 
 145. Another principle which furnishes a regu- 
 lator, but of delicate adjustment, is that of the 
 ^ pendulum. Supposing D to be the 
 
 tubular opening, by which air enters 
 to the stove, and B to be a conical 
 plug to fit it, hanging as a pendulum 
 from the point A ; evidently the cur- 
 rent of air entering to feed the fire, 
 would impel the plug more or less in- 
 wards, and the stronger the draught, 
 the more would the plug be impelled 
 inwards. But the plug being conical, the more it 
 entered the tube, the less space would be left 
 around it for the passage of air ; and the diminution 
 i 2
 
 116 REMARKS ON MANUFACTURING 
 
 of passage and speed of draught being properly 
 combined, the quantity of air entering, and therefore 
 the amount of combustion, would always be the 
 same. The combustion would be quickened or 
 slackened at will, by turning the screw at A, 
 which causes the plug to hang nearer or farther 
 from the opening. 
 
 146. The kinds of regulator now described are 
 only a part of what would be likely to occur to a 
 person possessing aptitude for such speculations, 
 and having present to his mind the leading idea of 
 the self-regulating fire. But to a person who has 
 not ready apprehension of such subjects, even a 
 longer description, than here given, might fail to 
 convey a clear notion, and at any rate, to prove a 
 sufficient direction for constructing. A great object 
 is to make well whatever form is chosen. I have 
 ascertained that any one of those now described 
 will answer perfectly. The form treated of in Art. 
 136, with the throttle-valve described in Art. 137, 
 is what I have chiefly had in use. Its excellences 
 are its simplicity, its being visible, its being almost 
 as easily replaced if injured, as a lamp glass, and 
 that every body can at once understand it, and to 
 get it mended would be independent of any more 
 skilful help than could almost any where be ob- 
 tained. 
 
 147. The part of a regulator containing the air, 
 the expansion of which is to work the valve, should 
 always be placed within the stove, and high 
 in it. If it be not within, instead of corresponding 
 always to the state of the fire as is intended,
 
 THE THERMOMETER-STOVE. 117 
 
 it will be affected only by the temperature of 
 the outer case, which receives and yields heat 
 slowly. If it be not near the top of the stove, it 
 may, at the first lighting of the fire, remain for 
 a considerable while nearly unaffected, and so 
 allow the combustion to become excessive. In 
 either of the cases supposed, it would resemble, 
 not the bridle of the skilful horseman, which acts 
 almost by anticipation, and maintains the steady 
 pace which is safe and useful ; but the rein of the 
 novice, which is slackened and tightened out of 
 time, wasting the horse's strength and incurring 
 danger. 
 
 148. Whatever be the form of heat-governor 
 used for a stove, the air-door or valve part should 
 be hung so as to allow of its being fixed by hand 
 in any determined position ; that is to say, should 
 be convertible at will into a hand-regulator. Thus, 
 if the thermometer part should by accident be 
 injured, the stove, although lamed, would still 
 remain useful. The thermometer-regulator is so 
 easily made, and confers so many important advan- 
 tages not attainable without it, that a person who 
 understands its uses can never rest satisfied with a 
 hand-regulator. It should be known, however, that 
 a person who has watched for some time the work- 
 ing of a stove in any place, may judge so well of 
 the degree in which the air-valve requires to be 
 open to suit the particular chimney, in ordinary 
 states of wind and weather, that he may obtain 
 many of the advantages of the stove by the hand, 
 regulator; that is to say, by the valve governed by
 
 118 REMARKS ON MANUFACTURING 
 
 himself instead of by a thermometer. And the 
 action of a hand-regulator may be rendered still 
 more steady, by establishing a direct communica- 
 tion through a tube, from the ash-pit to the 
 chimney-flue; in which case the constantly varying 
 draught of the chimney influences the enclosed 
 fire scarcely more than the varying barometrical 
 state of the atmosphere influences any fire in the 
 open air. With a hand-throttle valve in such a 
 tube, and a hand-regulator in the ash-pit door, 
 considerable uniformity of combustion may be 
 obtained, but still very much less than with the 
 complete heat-governor. 
 
 149. There are now in the arts of civilized 
 life, so many examples of mechanical arrange- 
 ments, which cause the few simple and uncon- 
 scious forces of nature to perform work of the 
 greatest complexity and nicety, that we have 
 ceased to wonder at them; otherwise, even the 
 arrangements in a self-regulating stove might not 
 be contemplated without considerable interest. 
 We know the difficulty to human head and hands 
 of managing a common fire, so as to have even an 
 approach to regular action, and if the fire be wanted 
 through the night and day, at least two persons 
 must be employed about it; but here we see a 
 simple apparatus, which, if a few pounds of fuel 
 be entrusted to it in the morning > will so use that 
 during the four-and-twenty hours, that the most 
 able chemist could not equal the perfection of its 
 performance and all the valuable results spring 
 from the rising and falling of a little float on the
 
 THE THERMOMETER-STOVE. 119 
 
 surface of the mercury, as some confined air is more 
 or less expanded by heat. And still farther, this 
 float will, if desired, ring a bell to call for assist- 
 ance when any accident occurs to the stove, which 
 it cannot itself remedy as when the servant has 
 forgotten to supply fuel at the proper time, or to 
 rake the fire, or has negligently left the ash-pit 
 door open. In these, and in any other cases of 
 disordered action, the stove necessarily becomes 
 either too hot or too cold, and the little float 
 mentioned, then either rising above, or falling 
 below its natural limits, may release the detent of 
 an alarum bell, and so compel attention. 
 
 150. Having now described forms of the stove 
 and regulator, which exhibit in a clear light the 
 objects sought by them, and the principles in 
 volved in their action, it remains for me to show 
 by what simple changes upon, and additions to, 
 forms of stove already known, the same objects 
 may more or less perfectly be attained. 
 
 151. By the common Dutch stove with a long 
 flue, as described in Article 31, the whole heat of 
 the combustion may be applied to use, and the 
 greatest possible economy of coal obtained, but 
 the atmosphere around such a stove is unsuitable 
 to human respiration, and to many persons at once 
 insufferable, because of the scorched, and other- 
 wise impaired condition of the air, produced by 
 the excessive heat of the surface of the stove, and 
 of the part of the chimney near the stove. Now
 
 120 
 
 REMARKS ON MANUFACTUEING 
 
 by merely placing the stove A, 
 and part of the chimney, in a case 
 or cover of iron, which case may 
 be a simple box or pillar, as here 
 shewn, or vase, with which a ther- 
 mometric regulator is connected, 
 the hurtful effects are prevented. 
 The scorched air from the surface 
 of the stove then serves only to 
 give a gentle warmth to the whole 
 iron cover, and through that to 
 the air of the room. According to 
 the length of chimney included 
 in the case will be the saving of 
 heat. When, in any thermometer- 
 stove, the smoke-funnel described in Article 127, 
 with a dome or cap, becomes a cover closely 
 fitting the fire-pot, the stove is thereby made to 
 belong to the modification now described. When 
 the fuel perfectly suited to the open fire-pot cannot 
 be procured, namely, stone-coal, coke, or charcoal, 
 this modification of stove is preferable to the 
 other. 
 
 152. This form of stove, and indeed any other 
 of the forms exhibited of the thermometer-stove, 
 may be said to compress together into one short 
 mass several yards of the chimney flue of a 
 common Dutch stove, rendering the temperature 
 of every part the medium or average, between 
 the nearly red heat of the part near the fire, and 
 the comparative coldness of parts farther off. The 
 box or outer case is, in reality, only a swelled
 
 THE THERMOMETER-STOVE. 
 
 121 
 
 portion of chimney-flue, in which the smoke is 
 caused to tarry until it yield up its useful heat. 
 
 153. Another modification, admitting of many 
 forms, is represented by the adjoining figure : A 
 
 is a simple stove-body or fire-pot, lined with such 
 thickness of brick, or other slow conductor of heat, 
 that the external surface shall never become over- 
 heated. The flue B C D E constitutes a circuit 
 of any extent and shape, in which the smoke re- 
 volves and gives out its heat : F is the chimney 
 flue. The hot air ascends from the stove along 
 B C, mixing with the revolving mass coming from 
 E, and maintaining the whole circuit at nearly the 
 same temperature. A small portion of the revolving 
 mass escapes into the chimney at F, to let an 
 equal portion of fresh air enter to feed the com- 
 bustion . The regulator obeys the heat of the circuit 
 B C D E. A passage or communication exists 
 between the flue above A, and the chimney flue F, 
 by which the hot smoke maybe allowed, if desired, 
 to pass away directly, instead of performing the
 
 122 REMARKS ON MANUFACTURING 
 
 circuit, and leaving its heat in the room. The small 
 flue may be continued all the way round. 
 
 154. Another modification 
 is represented by this figure, 
 viz. a vessel of water, of 
 pillar-shape, made to rest 
 on the fire-pot A, of the 
 last figure. The flue passes 
 through the water, and heats 
 it. A spiral pipe from the 
 top to the bottom of the 
 water keeps it always cir- 
 culating, and contributes to 
 diffuse the heat. 
 
 155. This figure represents the stove fitted for 
 
 a hot-house or green-house, by the flue being 
 carried in a slanting direction (it might be ho- 
 rizontal) to a considerable distance from the stove, 
 thereby distributing the heat more suitably. The
 
 THE THERMOMETER-STOVE. 123 
 
 flue is surrounded by another .pipe, which forms 
 part of a circuit, acting to equalize the tempera- 
 ture of the whole. 
 
 156. I shall conclude this part of my subject by 
 describing ways in which the advantages of ther- 
 mometer-stove economy and self-regulation, may 
 be obtained from an open fire. The arrangement 
 maybe called the " coal torch," or " coal candle," 
 fitted to give both light and heat. Persons who 
 recollect seeing, many years ago, the stove called 
 Cutler's, will very readily understand this. Cut- 
 ler's was a deep, narrow box of iron, with the 
 bottom made to slide up and down like a piston, 
 and which, when filled with coal and lighted at 
 the top, exhibited the upper exposed part of the 
 coal in a state of rapid combustion, with a long 
 flame of gas issuing from it, the combustion being 
 regulated by screwing up or down the moveable 
 bottom, and thereby causing the burning mass to 
 protrude more or less into the air, in the same way 
 as the wick of a lamp protruding from its tube or 
 channel is screwed up or down, and is thereby 
 made to produce a large or small flame. Now if a 
 cylindrical box, made of thin wood bent, about 
 two feet deep and eight inches wide, be filled with 
 common bituminous or flaming coal, and be lighted 
 at the top, it will immediately burn like a huge 
 torch or flambeau, and the combustion may be 
 regulated by placing it in a cylindrical metallic 
 case, which fits it, and gradually raising it above 
 the edge of the case as it is wanted to burn. It 
 will be, in fact, a great lamp, with a wick of solid 
 coal or coke red hot and burning, and with the
 
 124 REMARKS ON MANUFACTURING 
 
 pitch or bitumen of the coal for its oil, and it 
 wants no snuffing, because the wick itself is con- 
 sumed as it rises. If such a torch be caused to 
 send its smokeless flame into the mouth of a thin 
 metallic globe, as capacious as a common stove, 
 placed over it, from which globe a tube or flue passes 
 to the chimney of the room, all the noxious pro- 
 ducts of the combustion of the torch fire will pass 
 away by the chimney, while the light and radiant 
 heat of the fire will be diffused in the room, and 
 the greater part of the heat of the smoke also will 
 be given to the room through the surface of the 
 metallic globe, just as happens with the close stove. 
 There will be, therefore, nearly the economy of 
 the close stove. To obtain a thermometric regula- 
 tion of the fire, it is necessary to hang around the 
 upper part of the metallic case of the torch another 
 shorter case or tube, nearly but not quite touching 
 the first, so supported by a spring, or at the end 
 of a lever balance, that a weak force may suffice 
 to lift or depress it, and thereby in effect to 
 lengthen or shorten the torch case, and excite or 
 damp the combustion ; and the force used to effect 
 the motion would be that of any of the forms of 
 thermometer above described, made large enough 
 and strong enough for the purpose. Many forms 
 and modifications of this kind of fire will imme- 
 diately be suggested to persons likely to try the 
 construction of it. I need hardly observe, that the 
 smoke or hot air from a common fire, in a common 
 grate, ma)', by a tube with a trumpet mouth placed 
 closely over the fire, be caught and sent into such 
 a globe as described above, suspended in the room,
 
 THE THERMOMETER-STOVE. 125 
 
 or into any circuit of tube, such as seen at Article 
 153, to leave its heat in the room before departing 
 by the chimney. 
 
 2. Fixing the Stove. 
 
 157. The first object demanding attention, is to 
 close the chimney completely, except where the 
 flue of the stove enters ventilation being pro- 
 vided for otherwise. Some persons for this purpose 
 have used a chimney board, with a plate of iron in 
 its centre, through which was a hole, just fitting 
 the stove flue. Others have shut the register of 
 their chimney until only opening enough remained 
 to admit the flue of the stove, and then have closed 
 all around with plaster, &c. The convenient way 
 for a permanent fixing, is to take out the old grate, 
 and build up the space as an alcove, in which the 
 stove may stand. If proper coal be used, ordinary 
 sweeping can never be wanted, and therefore, it is 
 not necessary to leave a hole, for a sweep to enter. 
 If such hole be left, however, it should be as low 
 down as possible, and it must be perfectly closed, 
 by plaster or otherwise. A very small opening in 
 the chimney will waste much heat, will allow 
 some smoke to be drawn into the room every time 
 the door is hastily shut, and will favour the occur- 
 rence described in the next paragraph. 
 
 158. The stove flue of metal placed within the 
 brick chimney should not rise much above the 
 level of the body of the stove, for the draught of 
 a long iron flue would cause the fire to burn when 
 the brick chimney were not drawing ; and if, by 
 accident or otherwise, there were any communi-. 
 cation between the chimney and the room, the
 
 126 REMARKS ON FIXING 
 
 smoke or gases from the burning stove would 
 return and spread almost as if proceeding from a 
 brazier in the middle of the room. With a very 
 short flue, on the contrary, want of draught in the 
 chimney would check or extinguish the combus- 
 tion in the stove, and thus warn attendants of the 
 true state of things. So great yet is popular igno- 
 rance respecting combustion and its products, that 
 if heat were obtained by burning, in a close box 
 or case without a chimney, a fuel so prepared, 
 that the carbonic acid and other matters produced 
 in the combustion remain invisible, many persons 
 saying that the fire consumed its smoke, would 
 have to learn that the poison of the smoke, though 
 invisible, was still there. 
 
 159. As so little air ascends the chimney, the 
 opening at the top of ordinary chimneys, as well 
 as their general width, is too great. It answers 
 a good purpose to put on the chimney pot a coni- 
 cal cap, with the apex cut off, so as to leave an 
 opening of only four inches diameter. 
 
 160. When the stove is to be used with a 
 descending flue that is to say, to stand like a 
 desk or pedestal in the middle of the floor, with 
 the flue passing underneath the floor to the ordinary 
 brick chimney it is necessary to adopt means 
 which shall ensure the arrival of as much heat in 
 the brick chimney as will produce sufficient draught 
 to maintain the combustion. This is done, first, 
 by making the stove itself altogether of cast iron, 
 so that its thickness may prevent the too great 
 cooling of the air within ; secondly, by making the 
 concealed horizontal flue also of slow conducting 
 material, as of cast iron surrounded by brick, or
 
 THE THERMOMETER-STOVE. 127 
 
 of brick alone; and, thirdly, by having a door 
 near the bottom of the brick chimney, through 
 which some fire may be introduced to heat the 
 chimney, so to cause draught from the stove, until 
 the stove itself, and its horizontal flue, be suffi- 
 ciently heated and in action. The peculiarity of 
 the thermometer-stove, that it is always alight, 
 makes it very suitable for the descending flue, the 
 objection to which often is, the difficulty or trouble 
 of lighting the fire, or making the flue draw. 
 
 3. Using the Stove. 
 
 161. Kinds of Fuel. It is very important to 
 observe that the fuel for this stove, where the fire- 
 pot is open to the body of the stove, must be non- 
 bituminous that is to say, must be incapable of 
 producing smoke or flame such as rises from a 
 common fire of Newcastle coal, or wood. It must 
 burn with the appearance of red-hot stones, as 
 do charcoal and coke, and the stone coal, called 
 also anthracite, existing abundantly in Wales, 
 North America, and elsewhere. This necessity, 
 instead of being a hardship or disadvantage, 
 is, on the contrary, a good, for it renders fuel of 
 inferior cost, as precious in use as the dearest. The 
 reason of the necessity is, that the stove being 
 closed, no air can reach the fire but what enters 
 by the ash-pit. That air then ascends through the 
 red-hot fuel, and burns with it, losing in that 
 ascent all its power of farther supporting combus- 
 tion. If any pitch, gas, or other inflammable 
 matter, therefore, be disengaged from the fuel at 
 the upper surface of the fire, as no pure air can
 
 128 REMARKS ON USING 
 
 reach it to burn with it, and produce flame, as over 
 a common open fire, the volatilized pitch remains 
 unburned and wasted, and quickly condenses in 
 the stove and flues, choking up all the passages, 
 and the evolved carburetted hydrogen, or coal gas, 
 may accumulate in the top of the stove, in such 
 quantity as to make an inflammable mixture, liable 
 to become on the door being opened, a large flame, 
 of the same nature as what is seen in miniature 
 flickering and exploding over every common coal 
 fire. The stone coal from Wales is now used in 
 many important mnufactories in London, as in 
 the brewhouse of Sir Henry Meux, where, mixed 
 with a little Newcastle coal, it answers admirably, 
 and is free from the nuisance of smoke. That 
 other brewers and great muanufacturers should be 
 permitted still to use common coal, darkening and 
 poisoning the atmosphere of the metropolis, when 
 proof exists in the practice of one public-spirited indi- 
 vidual of the possibility of avoiding the evilswithout 
 private loss shows that there are defects remain- 
 ing in the London police laws. Some of the Welsh 
 coals have in them ninety-seven per cent, of pure 
 carbon, and therefore only three per cent, of any 
 thing else. Some of the Newcastle coal has thirty 
 or forty per cent, of bituminous matter, convertible 
 chiefly into gas. The common coal of North 
 America is stone coal, or anthracite, and so much 
 more difficult to inflame than ours, that, until 
 lately, the people generally did not believe it 
 could be used as fuel : it is now, however, in 
 almost universal use. In the thermometer-stove, 
 the fire-pot keeps the ignited fuel so closely toge-
 
 THE THERMOMETER STOVE. 129 
 
 ther, and, by being of thick non-conducting sub- 
 stance, confines and concentrates the heat so much, 
 that stone coal burns in it perfectly without any 
 admixture, and is better fuel for it than even coke 
 or charcoal, by reason of the little bulk in compa- 
 rison with the weight or quantity. In situations 
 where only wood or bituminous coal can be ob- 
 tained, these may be used with safety and with- 
 out much waste, by having the close funnel or flue, 
 described in Article 150, or by leaving the common 
 stove door more or less open, to admit pure air to 
 inflame the generated gases ; and in this case, if 
 desired, the stream of pure air may be, by a tube, 
 carried directly to the fire. 
 
 162. Lighting. The stove, when the upper fuel 
 door and the ash-pit door are both open, exhibits 
 merely a common fire-place, and the fire may be 
 lighted in the ordinary way, by mixing wood and 
 coal, or by putting a large shovelful of burning 
 coal into the grate, with fresh coal above it. But as 
 the ash-door would admit so much air as rapidly 
 to overheat the stove or too quickly to consume the 
 wood, it should be shut immediately, that the 
 supply of air may be furnished through the valve. 
 The upper door should then be left open more or 
 less, until the bituminous matter appearing as 
 smoke or flame be nearly exhausted. Where there 
 happens to be little draught in the chimney, as in 
 warm days, so that the fire will scarcely begin to 
 burn, a sheet of paper, or some wood shavings, may 
 be burned in the top of the stove to warm the 
 chimney ; a bellows may have its nozzle fitted to 
 the air-entrance, and will very quickly make the 
 K
 
 130 REMARKS ON USING 
 
 fire blaze like that of a smith's forge. Lighting a 
 fire with much wood, and closing the door too 
 soon, endangers accumulation of inflammable gas. 
 By partially closing the door, however, the draught 
 may be increased without inconvenience. The coal 
 used should neither be in very large pieces nor 
 very small. A mixture of sizes is best, unless the 
 whole could be procured in the state of cubical 
 pieces of one or two inches. 
 
 163. Quantity of Fuel. As the quantity is only 
 a small part of what would be needed for an open 
 fire, the necessity for charging the stove occurs in 
 proportion more seldom ; and as no waste arises 
 from having a large quantity of ignited coal in the 
 stove, provided the entrance of air is controlled 
 (for expenditure is proportioned only to the air 
 admitted), there is an advantage in having a large 
 fire-pot. This may hold coal to last for about thirty 
 hours; but then, like a watch, which is always 
 wound up before it can run down, the fire, to pre- 
 vent its falling so low as to disturb its uniformity, 
 should be made up perhaps night and morning. 
 If it were desired to have a fire which should last 
 very long without being touched, it would be 
 necessary to have either a fire-pot larger than 
 usual, or to invert a basket of wire, filled with 
 coal, over the fire, from which coal might descend 
 as wanted. In^such a case, it would be necessary 
 also to have the fire-bars more than usually open, 
 to prevent ashes being retained and choking the 
 fire. 
 
 164. The ashes may be taken away every morn- 
 ing, if much fuel be burned, but seldomer if not.
 
 THE THERMOMETER STOVE. 131 
 
 It may be convenient to have a drawer in the ash- 
 pit to receive them, which can be carried away at 
 once, without raking or other motion, which raises 
 dust ; or instead of the drawer, to have a close box, 
 with its mouth fitted to the door of the ash-pit, 
 and with a rake passing through it by which the 
 ashes may be drawn into it without a particle of 
 dust being allowed to escape. 
 
 165. Raking or poking the fre. The fire in the 
 stove may be extinguished in two ways, besides its 
 wanting fuel and wanting air, viz. first, by having 
 the coal so small and closely packed, that air 
 cannot pass through it to maintain the combustion; 
 secondly, by the ashes or clinkers accumulated 
 below, and similarly obstructing. The preventive 
 of these accidents is to rake the fire from below, 
 once or twice in the twenty-four hours, according 
 to the quality of the fuel. It will depend on the 
 width of space between the bars of the grate, and 
 on the nature of the coal, whether frequent raking 
 may be necessary or not. 
 
 THE ERRORS MOST LIKELY TO BE COMMITTED 
 BY PERSONS, ON FIRST MAKING, FIXING, 
 AND USING THE THERMOMETER-STOVE. 
 
 Errors in making. 
 
 166. Not being aware of the exceedingly small 
 quantity of air required to support the combustion, 
 and therefore not making the ash-pit with its door 
 and air- valve sufficiently close. The consequence
 
 132 ERRORS IN MAKING 
 
 is, that the fire is insufficiently controlled, and 
 burns so as to overheat the box, and to put the 
 regulator for the time out of order. Whenever the 
 box becomes too hot with the valve closed, there 
 is imperfect workmanship. The proper security, 
 therefore, is to have the ash-pit and exterior of 
 the fire-pot cast in one piece, and to let the mouth 
 of the ash-pit appear through the front of the 
 stove, to receive the ash-pit door, accurately fitted. 
 
 167. Placing the fire-pot too near the side or 
 the bottom of the stove, so as to overheat the 
 part. When there is the least smell from the stove, 
 either the whole is overheated, or the fire-pot is 
 heating it unequally ; and in the latter case, there 
 is faulty workmanship. The ash-pit may have 
 a tile between it and the bottom or side of the 
 stove, to prevent the overheating of the bottom 
 or side. 
 
 168. Neglecting to see that the sand -joints, if 
 there be any, and all other joinings, are perfect. 
 When a joint above the fire is not perfect, some of 
 the gases may escape through it every time the 
 door is opened, and may give smell to the air of 
 the room. While the stove-door is closed, the 
 draught of the flue renders every aperture in the 
 stove an inlet for air; but, with the door open, 
 every aperture above the door may be an outlet. 
 This marks the importance of not opening the 
 stove-door unnecessarily, as at first persons are 
 likely, from curiosity, to do. 
 
 169. Having regulators which, from friction or 
 other cause, do not work. No one of the regulators 
 here proposed requires such nice workmanship as
 
 THE THERMOMETER STOVE. 133 
 
 an Argand lamp, or a common wooden clock, 
 which costs a few shillings. There will be no 
 excuse, therefore, for the manufacturer not making 
 whatever form of regulator he may adopt abso- 
 lutely certain in its action. No regulator should be 
 accepted which is not exposed to view, and so 
 simple, as to be easily mended or replaced by an 
 ordinary workman. 
 
 Errors in falng. 
 
 170. It is common to forget the importance of 
 closing the chimney around the flue entirely. Any 
 aperture there, besides being exceeding wasteful 
 of heat, may let smoke return. 
 
 171. It is common to place a stove in a small 
 outhouse, as a conservatory, which has a short 
 chimney, between which out-house and the dwell- 
 ing there is an open passage or communication. 
 In such a case, the long chimneys of the house 
 will overcome the short one of the out-house, as 
 the long leg of a syphon overcomes the short leg ; 
 and the stove will not burn while the communica- 
 tion remains open. The error would be doubly 
 great, if the stove had a descending flue. If the 
 communication can be completely interrupted, by 
 shutting doors or otherwise, the stove will act 
 well ; or for such a case the stove may be made 
 absolutely close, by having the doors ground air- 
 tight, and causing the air-feeding or supply pipe 
 to lead from the outside near to where the chimney 
 terminates. Thus would the two columns of air 
 be under the same pressure, and the warmer would
 
 134 ERRORS IN FIXING 
 
 certainly be forced up. There might be cowls, 
 looking opposite ways, placed on the tops of the 
 two tubes. 
 
 172. A similar error exists where a stove and an 
 open fire are placed in the same or in communi- 
 cating rooms, even if they have chimneys of the 
 same length. The strong chimney, or that sending 
 up and wasting much heat, will overcome the 
 other, and draw back into the room all the gases 
 or smoke of the stove ; just as the chimney of one 
 drawing-room with a strong fire is seen to over- 
 come that of an adjoining drawing-room with a 
 weak fire. A gentleman put a stove in his study, 
 which stove acted perfectly for some time ; but, 
 one day, having lighted a great fire in a commu- 
 nicating room, the chimney of the stove returned 
 the whole of its contents. There is absolutely 
 no situation, however unfavourable to obtaining 
 a chimney action, in which a thermometer-stove 
 may not be placed to perform in the most perfect 
 manner, if instead of by a chimney, the draught 
 be produced by any of the mechanical means 
 for giving motion to air ; described here under the 
 head of ventilation, and the smoke, or gases, may 
 then be sent along a small tube in any direction, 
 and to any distance, with ease and certainty. 
 
 Errors in using. 
 
 173. Attempting to light the fire with a cold 
 chimney in a warm day, without first heating the 
 chimney by the common means of a handful of
 
 THE THERMOMETER STOVE. 135 
 
 straw or a sheet of paper, inflamed in the flue or 
 top of the stove. 
 
 174. Producing a burst of gas flame from the 
 stove. It is familiarly known to those using the 
 common Dutch stove, that when wood or bituminous 
 coal is employed as fuel, there is disengaged from 
 the fire, so as to fill the upper part of the stove, 
 a quantity of gas, which darts out as a long flame, 
 whenever, by opening the stove-door soon after the 
 fire is lighted or coal has been put on, atmospheric 
 air is admitted to mix with the gas in contact with 
 the fire. The phenomenon may be called a semi- 
 explosion, although differing exceedingly in vio- 
 lence from the true explosion of gas occurring in 
 mines, or near gas pipes, by reason of the large 
 quantity of carbonic acid gas always mixed with 
 the air. Now the same phenomenon may, by gross 
 carelessness, be produced in the thermometer- 
 stove. It cannot occur if proper fuel (Art. 158) be 
 used ; and not even with improper fuel if the stove 
 door be not closed too soon after fresh fuel has 
 been put on, and then opened soon after ; and 
 it cannot occur even with improper fuel and bad 
 management of the doors, if the cap (Art. 125) be 
 kept on the fire-pot. 
 
 175. Leaving the ash-pit door open. 
 
 176. On seeing the stove first lighted, and not 
 feeling so much heat to be radiated from it as from 
 a common fire, the believing that it is not giving 
 enough heat, and therefore with impatience open- 
 ing the ash-pit door even for a little while, which 
 may rapidly heat the whole to excess.
 
 136 ERRORS IN USING 
 
 177. Believing that there is a saving of fuel, by 
 having the fire alight for only half a day, instead 
 of constantly. Besides the expense of wood for 
 lighting, more heat and fuel may be wasted in 
 a morning hour, during which the fire is exces- 
 sively urged, than during six succeeding hours. 
 The action of this stove is not to give out a sudden 
 and wasteful rush of heat, but to warm steadily 
 and gently, like the mild season itself. In country 
 houses and offices, however, which are used for 
 only a few hours in the day, persons may choose 
 to light the fire daily, and let it burn out. If so, 
 it should be lighted two or three hours before 
 persons come to the office, and should be charged 
 with only fuel enough to burn for the hours 
 required. 
 
 CONCLUSION. 
 
 178. The first stove made, as described at arti- 
 cle 49, and which I exhibited in the Theatre of 
 the Royal Institution, was made for me by Mr. 
 Huxley, of 16, Castle Street, Long Acre. Although 
 prepared in a very few days from the time of my 
 giving the order, and therefore roughly put toge- 
 ther, it was such as to prove most satisfactorily all 
 the qualities of the contrivance. The external 
 case and its door were tolerably close. The ash- 
 pit, internally, was made air-tight by sand cover- 
 ing the joinings. The ash-door and valve I could
 
 CONCLUSION. 137 
 
 shut so as sufficiently to control the fire. In a 
 word, I had in it a fire under command, to which I 
 could apply any fit thermometer as a regulator. 
 Yet even after this specimen of actual performance 
 existed as a direction for future labour, Mr. Hux- 
 ley had difficulty, as happens with all new things, 
 in getting his workmen to understand exactly the 
 ends or purposes of what they were doing, and 
 he had disappointments, therefore, from doors not 
 close, and ash-pits not close, and regulators which, 
 from friction, not being balanced, &c., did not 
 work well, all which occurrences, when I hap- 
 pened to hear of them, were disappointments to 
 me also, who, for a moment, had thought that a 
 thing so simple in itself, and of which every part, 
 if properly made, must act with as much certainty 
 as a stone falls to the earth, should at once have 
 been produced, as perfect as it existed in my own 
 conception but Mr. Huxley has now, I hope, 
 made arrangements to ensure that success in all 
 cases which has attended his best performances. 
 And at any rate, I trust that the explicit directions 
 here given, and the knowledge of how perfectly 
 the stove acts when well made, will prevent errors 
 being committed anywhere in future. Other persons 
 also, guided by the description given in my public 
 lecture, have made the stove with success ; and I 
 learn that now many leading manufacturers, as the 
 Messrs. Bramah, Cottam and Hallam, May and 
 Mcniit, and others, are waiting for the publication 
 of this tract, to engage largely in the work. I 
 hope, therefore, that while all who engage in the
 
 138 CONCLUSION. 
 
 manufacture maybe well requited for their labour, 
 the public will have offer of abundance, and 
 variety, and out of the honourable competition of 
 makers, will obtain stoves of excellent quality, 
 and at moderate prices. A thermometer-stove, well 
 made, well set, and once lighted, will, with ordi- 
 nary care, keep its fire burning steadily for the 
 whole season. 
 
 THE END. 
 
 Printed by 
 
 J. L. Cox and Sons, "}3, Great Queen Sir 
 Lincoln's-Inn Fields,
 
 
 THE LIBRARY 
 UNIVERSITY OF CALIFORNIA 
 
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 STAMPED BELOW. 
 
 Series 9482