Simple Water Testing b r PHILIP EDELMAN THE JOSEPH G. BRANCH PUBLISHING CO. Return this book on or before the Latest Date stamped below. A charge is made on all overdue books. U. of I. Library Noii rit 14685-S Simple Water Testing BY PHILIP EDELMAN CHICAGO The Jogeph G. Branch Publishing Co. 1913 Copyright, 1913, by Joseph G. Branch. THE HENRY O. SHEPARD CO., PRINTERS, CHICAGO. 0 La i k> 4 (T C^7 SI' ^ 6 ' . tdtf* ELECTRICAL EilCIKEEWMO PREFACE This book gives the practical worker a useful under- standing of water, so as to enable him to analyze quickly and with but little expense boiler feed-water, and to show how the ill effects of impurities may be regulated. Natural water is never found pure. Rain water is the purest natural water. As the rain falls it washes the gases and dust from the air. Upon striking the ground, it takes up impurities from the soil, the rocks and plants. Part of the water flows on the surface, absorbing more impurities. On filtering through the ground, the water loses most of its organic impurities which were absorbed from vegetable and animal de- posits on the surface. As it does this, however, it also dissolves and absorbs mineral matter and gases. Since all boiler feed-water must necessarily con- tain these impurities to a greater or lesser extent, the engineer must know how to avoid same, and this book will tell you in a clear and practical way how to do it. It explains it all so clearly that you can analyze the water yourself, and be able to adopt proper remedies for counteracting the ill effects of such impurities. May 12, 1913. THE AUTHOR. I 283860 Simple Water Testing CHAPTER I. The purpose of presenting this material, under the title of “Simple Water Testing,” is to give practical workers a useful understanding of water, to enable them to analyze feed-waters, and to show how the ill effects of impurities may be regulated. Occurrence of Water in Nature. There are three general forms of water : the liquid, vapor, and ice. Water as a liquid covers about three- fourths of the earth's surface. All animals and plants contain large quantities of water and soil, and porous rocks hold a considerable amount. Many substances, like paper, which appear dry, contain a large propor- tion of water. The human body is nearly seventy per cent water, and the foods that are required to sustain life contain large amounts. Water is continually evaporating from the surface of the oceans, lakes and rivers, from moist earth, from animals and from plants. As a vapor, water is present in the atmosphere, and when this vapor condenses it appears in the form of clouds, mist, fog, rain, snow, dew, hail and frost. As ice, water covers the polar regions and the tops of high mountains. Source of Water. Natural water is never found pure. Rain water is the purest natural water. As the rain falls, it washes gases and dust from the air. Upon striking the ground 2 SIMPLE WATER TESTING. it takes up impurities from the soil, the rocks and plants. Part of the water flows on the surface, absorb- ing more and more impurities. As streams, creeks and rivers, this water finally reaches the ocean. A large part of the rainfall soaks into the ground and gradually filters through the soil. On filtering through the ground the water loses most of its organic impurities which were absorbed from vegetable and animal de- posits on the surface. As it does this, however, it also dissolves mineral matter and gases. This water finally reaches the surface again as a spring or well. The most common mineral compounds which are found in water as a result of this filtering through the ground are : 1. Calcium and magnesium compounds. Water containing these is called hard water. 2. Chlorin and chlorids. 3. Carbon dioxid gas, alkaline matter and sulphur compounds. 4. Iron compounds. 5. Lime and magnesium compounds. 6. Traces of many other substances. These underground waters eventually enter into a lake or river. Since it is from these rivers and lakes that feed-waters usually come, it is well to note the manner in which impurities occur. In the first place it must be remembered that water is a great solvent. As a result, all water has more or less mineral matter and gases dissolved in it. The amount of mineral matter will naturally vary according to the soil which it has filtered through. The proportion of these min- eral impurities may mean a great difference in the usefulness of the water, as will be seen later. Simi- larly, the kinds of mineral matter found in the water are due to the nature of the soil through which it has passed. Since the soil varies greatly in different locali- ties, it follows that there are great differences in the SIMPLE WATER TESTING. 3 water in each district. This makes set rules and cal- culations in which water is concerned impossible for all localities. Supply from Rivers. River water contains the impurities from both the waters which have been filtered into the ground and surface waters. These surface waters form little brooks and creeks, and owe their impurities largely to the erosive power of water. Surface waters have minute organic matter, bits of animal and vegetable refuse, suspended in them. These are often so well suspended that the eye can not detect them, and again they may be so thick that the water is colored by them. River water, in addition to these impurities, con- tains matter from sewers, refuse from cities and fac- tories and other insoluble particles. Rivers often con- tain much suspended soil particles. Slow rivers are generally more impure than swift ones. Swift rivers, however, are liable to be more turbid than the slow streams because the suspended matter does not have a chance to settle. Sometimes the muddy appearance of river water is caused by the swift current washing the bed along with it. Such muddy water is called turbid water. The turbidity of rivers is greatest after heavy rains. The river overflows and is able to carry the softer soil on the banks along with it. Lake Water. Lake water is generally free from suspended mat- ter because the still water allows all insoluble matter to settle to the bottom. Lake water contains dissolved mineral matter. Feed- water. From the foregoing it will be seen that water in nature can not be absolutely pure. The questions which determine the utility of any water are : 4 SIMPLE WATER TESTING. 1. What impurities does the water contain? 2. What proportion of the impurities does it con- tain? 3. What is the nature of the impurities? 4. How can these impurities be regulated? This is in addition to the question of supply. It is absolutely essential to know these facts about the feed- water. Water is a deceptive substance. It may appear perfectly clear, have no offensive odor, taste or color, and still contain enough mineral matter to make it harmful. Good water is as essential to efficiency as good coal. When the water is evaporated in the boiler, the impur- ities remain in the boiler. Gradually this residue accumulates, and if the water used contains certain impurities, a solid crust forms inside the boiler. In course of time this crust becomes so thick that there is a loss of efficiency. Sometimes this crust can not be removed. The life of the boiler is shortened as a result. Certain mineral impurities have a corroding effect and cause much trouble. A practical worker may determine the nature of the impurities in his feed-water without much difficulty. The only apparatus necessary is a few test tubes, a burette and small portions of some simple reagents. These may be obtained from supply houses or, in the majority of cases, from a drug store. It must be remembered that in determining the nature of impurities, degrees of hardness, etc., very small quantities of the impurities are present in the water. It is therefore essential that great care should be taken in obtaining a fair sample. Any foreign mat- ter or chemicals which come into contact with the sample after it is taken will often change the results. Use clean glass containers for collecting the sam- ples. Mason jars, such as are used for canning fruit, are suitable. Regular gallon water bottles, used for SIMPLE WATER TESTING. 5 distributing drinking water, will also do for this pur- pose. When the water is taken from a tap or pump, some water should be allowed to run to waste first before filling the sample bottle. This insures a fair sample, but if water which has been standing in the pipes is used the results will not be reliable. Simi- larly, when taking samples from a river or lake, it is well to sink the bottle below the surface before remov- ing the cork or cover, in order to obtain samples free from the top scum. After filling the bottle nearly full it should be well corked or covered. The Testing. After the samples have been obtained, the next step is to test them. To test for turbidity in a general way, proceed as Fig. i. 6 SIMPLE WATER TESTING. follows. After shaking the bottle well to diffuse any sediment which may have formed, pour a little into a test tube. Hold the test tube, half filled, up to a strong light and look for suspended matter. If you have difficulty in finding the suspended particles or can not find them at all, the water may be regarded as practically free from turbidity. When these particles are very evident and the sample has a muddy appear- ance, even in ordinary light, a high turbidity may be inferred. Turbidity can be accurately measured. It is ex- pressed as equivalent to a certain number of parts per million of suspended matter of a particular fine- ness. While this would scarcely come under the title of “ Simple Water Testing,” the following simple method of measuring the turbidity will be found suffi- ciently accurate in case it should be desired. A bright new pin is fastened at the extremity of a meter-rod or yard-stick and the stick inserted in the water (see Fig. 1) until the pin can just be seen. The depth of the pin is noted from the stick, and by refer- ence to the following table the turbidity may be deter- mined : Depth of Pin. ^Turbidity. Millimeters. Inches. 10 794 31.26 15 551 21.69 20 426 16.77 30 296 11.65 50 187 7.36 75 130 5.12 100 100 3.94 150 72 2.83 200 57.4 2.26 300 43.2 1.70 500 30.9 1.22 1,000 20.9 .82 * According to United States G. S. SIMPLE WATER TESTING. 7 Hardness. An important property to determine is the hardness of the water. Hardness is caused by the presence of bicarbonates, sulphates, chlorids, or nitrates of lime or magnesia. Waters which are free from these com- pounds are “soft.” Hardness may be caused by a combination of several forms of the lime and magnesia. Hardness which is caused by the presence of bicar- bonates of lime or magnesia is only temporary hardness. Waters of temporary hardness are particularly impor- tant with respect to boilers. When the water of tem- porary hardness is boiled, the heat drives the combined carbonic acid off and leaves a solid residue which falls to the bottom of the container. The sulphates, chlorids, or nitrates or combina- tions of the lime or magnesia cause the water to be permanently hard. Permanent hardness of waters is another important property of water which has to be regulated for use in boilers. Permanent hardness can be removed by chemical treatment or by distillation. 8 SIMPLE WATER TESTING. CHAPTER II. Determination of Hardness. There are two reliable tests for hard waters. They are known as the “ Soap test ” and the “ Acid test.” Both are simple and the results are available in a few minutes. Briefly, they consist in taking an exact measured volume of water or solution of unknown strength and adding to this an exactly measured vol- ume of reagents of known strength. The indication is given by a change of color or other visible means, after the correct amount of the reagent has been added. This method is called the volumetric test, i. e., by volume instead of weight. The Soap Test. The soap test depends upon the fact that lime and magnesia compounds destroy soap in a proportionate quantity to the amount .of the compounds. In other words, the lime and magnesium salts combine with the fats of the soap, and an insoluble compound which can not make a lather is formed. When the mixture is shaken no lasting lather or foam can form unless there is a greater quantity of soluble soap than the given lime and magnesium compounds can destroy. The hardness of water is measured in “ degrees Clark,” or “ degrees Frankland.” In Clark degrees each degree corresponds to one grain of carbonate of lime in each gallon of water. In Frankland degrees, each degree corresponds to one part of carbonate of lime per 100,000. Since a gallon of water contains 70,000 grains, a Clark degree means one part in 70,000. SIMPLE WATER TESTING. 9 Thus, Frankland degrees give figures which are greater than when Clark degrees are used, in the ratio of 10 to 7. For Clark degrees the quantity of water which is tested is 70 cubic centimeters. This is approximately Yio of a gallon. For Frankland degrees the quantity of water tested is 100 cubic centimeters. The method in each case is practically the same. The results can be changed from Clark degrees to Frankland degrees, or vice versa, by multiplying the results by Vio or 10 A as the case may be. Method. Into a clean bottle put 70 cubic centimeters of the water to be tested. A half-pint glass bottle is desir- able for this purpose. The water is measured out by means of a burette (see Fig. 2). This is a graduated tube open at the top and also at the bottom ends. It is marked off in cubic centimeters and usually has sub- divisions. The bottom end is conical and has a piece of rubber tubing slipped over it. This tubing is closed by a pinch cock or a spring clip. After obtaining the 70 cc. of water empty the burette. Prepare a soap solution as follows : Put 1 dram (% ounce) of shaved castile soap into a mixture of alcohol and water (y 2 pint of spirit to pint of water). Shake it well, and let it stand for a time. It should be filtered through filter or blotting paper. Now, if exact results are not desired this solu- tion may be used as it is, but for more accurate results it must be standardized. This is done by testing its strength by means of water of known hardness. The solution is then gradually diluted with alcohol and water in the above proportions until the strength is exactly right. This can be done by making up a water of definite hardness with lime water and sulphuric acid, and then experimenting until the right strength is found. 10 SIMPLE WATER TESTING. For this checking of the soap solution make up the following test solution : 1. Lime Water. — Slake two ounces of quicklime by adding a little water. When cold, put it in a bottle Fig. 2. A BURETTE. with a quart of cold water and shake well. Let the lime settle, and filter through filter paper or blotting paper. Put in a clean well-stoppered bottle. 2. Standard Sulphuric Acid. — Dilute a very small SIMPLE WATER TESTING. 11 quantity of sulphuric acid with a large quantity of water until 11 y 2 cc. of the dilute acid will neutralize 5 cc. of solution 1. This will also be used later for the “ Acid Test,” so it should be saved in a stoppered bottle. Red litmus paper can be used for the indicator, but if phenolphthalein can be obtained it will be easier to use and also more sensitive. Litmus paper comes in little book packets. Phe- nolphthalein comes as little white grains. Before it can be used it must be dissolved in alcohol (about 10 grains to pint). One drop of the phenolphthalein solution suffices to show the pink color. When there is more acid than alkali the color is instantly removed. If red litmus paper is used, the lime water turns it to blue at first. When enough acid has been added (i. e., when the solution is neutralized), the color will be a light purple. Too much acid will turn the paper red again. 3. The standard water is made by taking the neu- tralized solution (5 cc. of lime and 11J4 cc. of acid) and diluting it with distilled water until it makes 70 cc. (using the burette). This standard water, if made according to directions, should be 11 degrees (Clark) hard. This means that if the soap solution previously prepared is standard, this standard water of 11^4 degrees hardness will destroy a like quantity of the soap solution. The Operation. Before testing the sample of water, the soap solu- tion must be tested and standardized as was just directed. Fill up the burette with the soap solution. It will be noticed that the liquid does not show a level surface, but is concave. In reading from the burette the lower curved line of the concave should be made to coincide with the graduation marks. This precau- tion should be observed in filling the burette, also. The reading is facilitated by holding a strip of white 12 SIMPLE WATER TESTING. paper behind the burette at the surface of the liquid. Now to the 70 cc. of standard water gradually add the soap solution from the burette by squeezing the rubber tube. A slight lather may form as the bottle is shaken from time to time, but the bubbles will not last if the proportion of salts in the water is greater than the soap which is added. More soap is added and the bottle is shaken after each addition. Continue until a lather is formed which will last for several minutes. The number of cubic centimeters, less one, of the soap solution added, indicates the hardness of the water in degrees (Clark). The one degree is deducted because distilled water which has a O hardness requires this slight quantity of soap to make it lather. It will be seen that 12^4 cc. should have been required for this standard water. If the soap solution is too strong it must be diluted until this is the case. Having standardized the soap solution, the sample of the water of unknown hardness is then tested in much the same manner. For the best results, only one cubic centimeter of soap solution should be added at a time. If no lather forms, then another cubic centi- meter is added, and again, and again. When a tem- porary lather begins to form, the quantity added each time should be less, as or ^ 1S important to find the point at which a permanent lather is found. When the approximate point is reached, shake the bottle briskly and then let it stand for five minutes. If at the end of this time a lather remains, even though it may be less in volume, the lather is permanent as far as the test is concerned. This may also be decided by listening to the breaking of the bubbles. Let the bottle stand for ten seconds after shaking it. Then listen to the bubbles. If they break with a hissing sound, more soap is needed. As soap is added the sound becomes less audible each time. When a permanent lather is reached there should be no sound at all. SIMPLE WATER TESTING. 13 Several tests should be made. They may not all agree, but a good average can be found. A good plan is to test the water undiluted at first and then to repeat after diluting it with an equal quantity of freshly dis- tilled water. When the two tests correspond, the water contains almost entirely lime compounds. When there are a few grains of magnesian salts present, the diluted water will show more hardness proportionally than the undiluted water. Indeed, lime and magnesia behave differently in the soap test. When the water contains lime alone the reaction between it and the soap is instantaneous. When magnesia as well as lime is present, the reaction requires some time. A water which is 10 degrees hard and having 5 due to lime and 5 to magnesia, will lather after only 6 or 7 cc. of soap have been added. After waiting three minutes the bubbles break up. No amount of shaking will produce them permanently again until the remaining amount of soap is added. Whenever this peculiarity is noted the presence of magnesia is indicated and its proportion may be roughly inferred. Whenever magnesia is present in any quantity the soap test is less reliable for these reasons. Again, equal quantities of lime and magnesia will not each destroy the same amount of soap. Mag- nesia destroys almost 1% as much as a like amount of lime. Remarks. When water contains vegetable matter it has a tendency to froth. This interferes but little, however. Some waters form a scum instead of a lather, at first. This scum contains imprisoned air, lasts a long time, and is very deceiving. It can not be heard and appears like a genuine lather. There is a way to deter- mine the difference. The water below the scum will be found to be nearly clear, while in the case of genu- ine lather in hard water the water becomes milky 14 SIMPLE WATER TESTING. before the lather is. formed. Water containing car- bonates acts in this way. Distilled water which is used should be fresh. It is apparent that there are many chances for in- accuracies in the* soap test. It does not take as long to test as it does to describe the operations. In gen- eral it is quite satisfactory. It does not distinguish' between permanent and temporary hardness. SIMPLE WATER TESTING. 15 CHAPTER III. The Acid Test. The temporary hardness of water is tested by the acid test. The hardness is determined by testing its alkalinity with acid. In general the test is reliable and simple. The carbonates of lime and magnesia which cause the temporary hardness of the water are weak alkalies. The amount of these carbonates present is found by neutralizing a known quantity of the water with a standard solution of weak acid. Methyl orange is used as the indicator. Methyl Orange. — This indicator is a pale lemon- yellow color in alkaline liquids. It is used in the acid test because carbonic acid does not affect its color. It is also a sensitive indicator. It keeps its yellow color as the acid is added until the exact point is reached at which the carbonates have been changed into sulphids, that is, the point at which the carbonates present are neutralized. The color then becomes a pale orange. As excess acid is added the color becomes pink, the shade varying according to the amount of excess acid used. Method. — Use the standard acid solution, prepared as directed. The hardness due to the carbonates of lime and magnesia is indicated by the number of cubic centimeters of acid necessary to neutralize the seventy cubic centimeters of water, as in the soap test. The methyl-orange indicator is made up by dis- solving six or seven grains in a pint of distilled water. Measure out the seventy cc. of the water to be 16 SIMPLE WATER TESTING. tested, taking all the precautions as in the soap test. Add only one drop of the methyl-orange solution. Fill up the burette with the standard acid solution. Add small quantities of the acid until the pale yellow color changes to orange. This change from yellow to orange or pink is only clearly visible in daylight. If it is necessary to work by artificial light add an extra drop of the indicator. The color change can be seen by holding the vessel containing the water in front of a sheet of white paper. Each cc. of the acid used neu- tralizes one milligram of the carbonate. The hardness is thus found directly. Remarks. — Some waters contain carbonate of soda. This impurity is an alkali but it does not cause hard- ness. The alkalinity as measured by the acid test will be greater than the actual hardness. This completes the “ hardness ” tests. Several trials should be made and compared. The tests should be repeated about once in every two months. The results will vary at different times of the year. The tests for hardness form the most important tests and in many cases are all that are necessary. The soap test determined the permanent hardness or the proportion of sulphates, chlorids, and nitrates. The acid test determined the proportion of bicarbonates. For com- parison it is well to test both boiled and unboiled samples of the same water. If there is much carbonic acid in the water the results will vary widely. The boiling of the water in this case drives off the com- bined carbonic acid and leaves the water softer. The difference between the hardness found for the unboiled sample and the boiled sample will give a fair indication of the temporary hardness. Permissible Hardness. — The question will arise as to what degree of hardness is permissible for steam purposes. It is certain that the softer the water is the SIMPLE WATER TESTING. 17 better it will be for this use. We might take a con- crete example. Suppose the water is found to have a total hardness of fifteen degrees. Suppose further that it is proposed to use this water in the boilers for a two hundred horse-power engine without in any way treating the water. It is difficult to understand how such a few grains of solid matter as this particular water contains could amount to any troublesome quantity. Suppose that each day some six thousand gallons of water will be evaporated in the boilers. Now, if each gallon of water contains fifteen grains of lime salts, there will be some twelve pounds of deposit or scale in one day, as follows : 6,000 gallons water. 15 (15 grains of salts to 1 gallon). 90,000 (total weight of residue in grains). Since there are 7,680 grains to the pound 7680)90,000 ( 11.7 + 7680 ^ 13200 7680 55200 53760 1540 In one month of twenty-six days this would amount to 304.2 pounds. At this same rate almost two tons would be de- posited in one year. These figures do not take into account any suspended organic or other particles. This deposit will stay in the boiler until it is re- 18 SIMPLE WATER TESTING. moved. Approximately one-half of the total deposit will form a hard scale. The operating engineer is well aware of this hard scale. He finds it on furnace flues, fire tubes, and circulating tubes. Aside from the corro- sion of the metal, a considerable heat loss results. The crust which forms inside the boiler is a poor heat con- ductor. A noticeable waste of fuel often results. Then there is the trouble necessary in cleaning out the boilers. There is no doubt but that scale always ruins boilers. Indeed, in some cases explosions have been caused by the continual formation of scale. The scale will sometimes crack, breaking away from the iron. The metal may be unable to withstand the sudden pressure and temperature increase and will give way. Flue plates especially are eaten away on account of scale.* Acid Waters.— Occasionally it will be found that a water supply is acid. Such waters have a marked corrosive effect on the boilers. To test for acidity a small sample should be taken of the water which is in the boiler, as well as a sample before the water reaches the boiler. Method. — Take a sample in a test tube from the gauge cock. Let it cool, and test for acidity with the phenolphthalein solution. Repeat for comparison, using very dilute sulphuric acid. (Standard acid solu- tion diluted four times.) Test the sample of water which has not entered the boiler in the same way. The acid is seldom found in injurious amounts. The acids present are usually organic acids and will be noticed more in small streams into which much refuse is thrown. The Test for Chlorids. — One of the factors which causes hardness is the presence of chlorids in water. * For the care and management of boilers, see Chapter 7, Volume 1, “ Sta- tionary Engineering,” by Mr. Branch. SIMPLE WATER TESTING. 19 If present in any large proportion, the water will surely form scale. In the tests for hardness the proportion of chlorids together with sulphates and nitrates has already been ascertained. The exact pro- portion of chlorids can be found by a tedious process which also requires some special apparatus, but it is omitted here. The test for chlorids depends upon the fact that when a solution of silver nitrate is added to a solution of the chlorid, a white, curdy precipitate of silver chlorid is formed. Method. — Dissolve a few crystals in distilled water. Silver nitrate is a white crystalline solid. Make a very dilute solution of salt and water, using ordinary table salt. (Sodium chlorid.) Fill a test tube one-third full of the salt solution. Pour a little of the silver nitrate solution over it. A white precipitate is formed. Repeat, using a sample of the water to be tested in the test tube. If chlorids are present the precipitate should appear. If there is only a very minute quantity of chlorids in the water, the precipitate may not show, but ordinarily the water will cloud slightly. Note. — In making up the solutions always filter same before using, unless otherwise directed. The Test for Sulphates. — Sulphates form one of the most common impurities in water. They always cause hardness, and water containing them always forms scale in boilers. Their proportion together with chlorids and nitrates (taking for granted that the water contains the three), is found by the tests for hardness. Like the chlorids, their independent pro- portion can be found by laborious methods with special apparatus. The test for sulphates depends on the fact that when a solution of barium chlorid is added to a solution of sulphate, a white, insoluble precipitate of barium sulphate forms. 20 SIMPLE WATER TESTING. Method. — Prepare a solution of barium chlorid and water. (See method under “ Chlorids.”) Make a dilute solution of sodium sulphate for comparison. Fill a test tube one-third full with the sodium sulphate solution and add some of the barium chlorid solution to it. The precipitate should at once appear. Repeat, using the sample of water to be tested. If sulphates are present the water should turn milky or cloudy. Nitrates or nitrites are tested for on account of their importance to drinking water. They are unim- portant with reference to water for steam purposes. Nitrate of lime may sometimes occur in water. Carbonate of Iron. — Carbonate of iron is liable to occur, especially when some waters stand in iron pipes for considerable time. It can be tested for in much the same way as was used for the chlorids and sulphates, using potassium ferrocyanid, prepared in a solution. It is seldom that enough of the iron car- bonate is present to show. Iron Tests. If a solution of potassium ferricyanid is made up with distilled water and used as before described, a blue precipitate forms which colors the dilute solution blue. A Delicate Test; — Take a small sample of the water, add a little pure hydrochloric acid to it and then add a little solution of potassium sulphocyanate. A red color or pink in dilute solutions is an indication of iron. These are good tests for iron. One or all may be tried, but the last one will generally serve the purpose. Calcium or lime is sure to be present in feed-waters. This may be proved by adding a solution of ammonium oxalate in distilled water to a small sample. The lime SIMPLE WATER TESTING. 21 is indicated by a white precipitate, or in a dilute solu- tion the sample becomes milky when treated with the ammonium oxalate. This will complete the simple chemical tests as far as water for steam purposes is concerned. Several trials should be made for comparison. Any one water will not necessarily contain all of the impurities which have been mentioned, or again, some may contain more. Having definitely determined the general nature and proportion of the impurities, it will be desirable to know what these impurities are likely to do when the water is used in the boiler, and also how the water may be treated to overcome the ill effects of the im- purities. 22 SIMPLE WATER TESTING. CHAPTER IV. Regulation and Purification. The Report. It may be desirable to keep a report of the results, especially if it is required by the employers. It is a good plan to do this in an orderly manner. An outline is shown in the illustration, Fig. 3. If this plan is followed out, the report should be dated and signed. The remarks may include any items which are not expressly provided for. ANALYSIS OF FEED-WATER. FORM FOR REPORT OF WATER ANALYSIS. Sample Date taken Conditions Date tested Turbidity Hardness (Permanent) Hardness (Temporary) Remarks Results. Acid present .... Chlorids Sulphates Carbonate of iron Remarks Signed Fig. 3. SIMPLE WATER TESTING. 23 Fig. 4. SECTIONAL VIEW OF THE WEBSTER EXHAUST STEAM FEED-WATER HEATER AND PURIFIER. 24 SIMPLE WATER TESTING. Effects of the Impurities. Having determined the probable composition of the water, it is desirable to learn what effects the indicated impurities are liable to have on the boiler. The first item is the suspended matter, which should always be removed before the water enters the boiler. A good method is to use a feed-water heater and puri- fier. One of these heaters is illustrated in Fig. 4. Besides removing the suspended matter these heaters also remove some of the impurities which are dissolved in the water. The substances which are dissolved in water at ordinary temperatures are precipitated when the solution is heated enough. To understand this better, try this experiment. Make a clear solution of lime water by dissolving a little slaked lime in water and filtering. Fill a test tube half full with this solu- tion and heat in a flame. The precipitate will then form. This is what takes place in part in one of these heaters. Acids. Organic Acids. Organic Matter. If the tests show any acid to be present, it will be necessary to neutralize the water with an alkali. The acids are bad for the boiler because they corrode iron. The remedy is to neutralize the water with small quan- tities of carbonate of soda or carbonate of lime. These reagents are added to the water, but it is rarely that water is found which is acid enough to require special attention. The reagents used for the other impurities usually take care of any acid that is present at the same time. Organic matter is removed in the same way as that of mineral matter suspended in the water. Much organic matter would do no harm in a boiler and might even do some good. It has the good properties of SIMPLE WATER TESTING. 25 keeping the scale which tends to form from other im- purities, in a soft removable form. Dissolved Mineral Salts. The dissolved salts in the water (as indicated in the hardness and special test) may concentrate to form a mineral deposit. The usual effect is the precipitates which result from the high temperature. Lime salts are a good example of this. At an ordinary tem- perature of 60-70° F. they are soluble, but at a tem- perature of 300° they are not. The ordinary forms (carbonate and bicarbonate) are precipitated at 212°, which is the boiling point of water. It is for this reason that these particular impurities may be removed by the feed-water heater and purifier. To remove the substance sulphate of lime by this method it requires pressure as well as the temperature of boiling water. The full boiler pressure is used, and the water has to be pumped into the heater. Carbonates. The carbonates of lime and magnesia form a scale in the boiler only when they are not kept in circula- tion and are heated strongly. This might occur if the boiler were emptied while hot. Sulphate of Lime. This substance always causes scale. The hardness of the scale which it causes may vary according to temperature, or the other impurities that are present. It is very desirable to remove this impurity. The carbonates and bicarbonates of magnesia be- have in the same way as the corresponding lime salts. Boiler Precipitates. Scale. — As has been pointed out, the sulphate of lime is soluble at ordinary temperatures, and insoluble at a temperature formed by steam under pressure. As 26 SIMPLE WATER TESTING. Fig. 5. PITMARKS ON SECTION OF BOILER TUBE. SIMPLE WATER TESTING. 27 a result, any water which is forced into the boiler and contains this substance, will lose it by precipitation. The precipitate of sulphate of lime is a heavy, com- pact crystalline solid. On account of these properties it settles rapidly, forming a hard scale. Any one who has ever tried to remove this kind of scale will vouch for its hardness. Unlike the sulphate, the carbonates are light and settle slowly. If no sulphate were present at the same time, these last would always form a soft scale, but when combined with the sulphate, a hard scale results. In general, a precipate always tends to stick to the sides of the vessel or boiler. Ordinarily, precipitated particles do not cohere to each other,' but lie in a state of suspension. The particles will not usually adhere to the other matter in the water, but a group of the loose crystals may be joined to form one large crystal by the addition of other crystals. If the soap test showed the water to be over eight degrees hard, the water is pretty sure to give con- siderable scale in the manner just outlined. In tube boilers the scale forms on the inside of the tubes. If the deposit is soft and loose it is readily removed by blowing. When any of the deposit once sticks to the tube it can be removed only with difficulty. This last kind of scale is removed only after considerable manual labor is expended. Even then it is seldom that all can be removed. At any rate it is poor policy to wait until the scale forms and then to remove it, as a remedy for the trouble. The better way is to either purify or soften the water. Calcium Chlorid. — Unlike the sulphate of lime, it is very soluble. It does not cause any deposit or crust alone. It may be removed the same as the lime sulphate and requires no special attention in most cases. When sulphate of magnesia is present, it may 28 SIMPLE WATER TESTING. cause hard scale by decomposing the sulphate, making sulphate of lime and chlorid of magnesia. The latter would be very corrosive and corrode the iron plates. Nitrate of Lime. — This is rarely found in feed- waters. Like the sulphate and chlorid of lime, car- bonate of soda will take care of it. Carbonate of Magnesia. — This compound resembles the corresponding lime salt. (See Carbonates.) Sulphate of Magnesia. — This compound is very soluble. Like calcium chlorid, it does not form scale itself. It is not corrosive. In the presence of other salts it is objectionable because it tends to prevent the efficient treatment of the other salts. (Soda will de- compose the sulphate of magnesia.) Chlorid of Magnesium. — This needs no special at- tention. It is removed in the same manner as sulphate of magnesia. It is very soluble and will form no scale alone. It is, however, very corrosive. On coming into contact with the iron plates, the free chlorin which results attacks and corrodes the metal. Softening by the use of soda, prevents this corrosive action. The soda combines with the chlorin to form common salt. Carbonate of Iron. — Iron salts in solution are un- stable and absorb oxygen. The resulting iron oxid is insoluble and deposits as a red rust. Silica. — Most waters contain a trace of silica. It is unimportant in the consideration of feed-waters. All of the soluble impurities in water are constantly concentrated in the boiler by the evaporation of the water in the formation of steam. The steam itself as it leaves the boiler is practically pure water. The impurities are thus left in the boiler to concentrate and accumulate, forming scale and corroding the iron. SIMPLE WATER TESTING. 29 Fig. 7. SHOWING OLD SCALB RECEMENTED TO BOILER BY SCALE-FORMING MATTER IN THE BOILER. 30 SIMPLE WATER TESTING. The Purification of Water. Ever since the steam boiler was invented, men have engaged in the problem of purifying the feed- waters. In the latter part of the eighteenth century it was proposed to soften hard water by using slaked lime. Dr. Clark patented his “ Lime Process,” for softening water on a commercial scale in 1841. The soda and lime process was invented a little later. These processes are still in use in a modified form, at the present time. The following processes and de- vices are used with varying results. Some are very good and the others are just the opposite. As far as is possible the list is arranged in the order of efficiency. There are some exceptions in the latter part of the list, however. 1. Softening and purification tank systems. 2. Boiler compounds. 3. Feed-water heaters and purifiers. 4. Filtration. 5. Mechanical boiler cleaners. 6. Surface blow-offs. Distillation is omitted because it is too expensive to be practical. The first two methods are entirely chemical. The remainder are largely mechanical. The feed-water heaters have already been mentioned. The chief defect of this method is that the action is incomplete. The temporary hardness of some waters may be almost entirely removed by the live-steam heater. The per- manent hardness can, however, only be partially re- moved by the exhaust-steam type of heater. In either case, the heater itself becomes clogged up and requires cleaning. In fact, it may be said that the better it is as a water purifier, the worse it is as a heater. SIMPLE WATER TESTING. 31 Chemical Reagents. The cheapest and best method of treating feed- water is the chemical method. The remedy for each special impurity has already been outlined. These Fig. 8. SHOWING COLLECTION OF SCALE IN TUBE. Fig. 9. CORRODED BOILER TUBE. chemicals may be used in either of the ways (1) or (2). The chief reagents used are tabulated below with the approximate cost of each. 32 SIMPLE WATER TESTING. Lime, Y\ cent per pound. Caustic soda, 2 cents per pound. Soda ash (sodium carbonate), 1 cent per pound. Trisodium phosphate, 4 cents per pound. Barium chlorid, 2 cents per pound. Barium hydrate, 4 cents per pound. Tannic extract (Com.), 2^4 cents per pound. Sugar, 6 cents per pound. ‘Many makers of boiler compounds use acids in addition to some of the above-named reagents. The lime and soda are the chief reagents. Boiler Compounds. A mixture of some of the above-mentioned reagents and often others is popularly known as a boiler com- pound. These compounds do not actually remove the impurities, but either combine with them to form a precipitate or change them into insoluble salts that will settle and can be easily removed. They do not keep the impurities out of the water, but are intended to make them harmless. By judicious use they can be made effective in many cases. The chief object is to prevent the formation of scale (hard scale). The reagents used are designed to cause a soft deposit to form instead of a hard one. For many years it has been a profitable business to make and sell various “ Ready-made ” boiler compounds. A glance at the table of reagents and at a budget of “ Compound Receipts ” would soon show this. While some of these compounds are questionable there are many which are really of some value. The chief defect is that, like patent medicines, one compound can not be a cure for every boiler. Like medicine, a special compound with the ingredients in the proper proportions must be made for each boiler. By chance a ready-made com- pound might just happen to be right for a certain boiler, but the chances are that it will not be. The SIMPLE WATER TESTING. 33 better way is to analyze the water and then make up the compound to counteract the impurities that are found. Tree offers are sometimes made, but, of course, the company expects to furnish the compound that it advises. If used too sparingly the compound can not do its work completely. On the other hand, when used in excess, foaming and wet steam are likely to result. While the weighing out and mixing of the compounds can be done by an inexperienced person with reasonable care, the computation of the correct proportions involves a knowledge of reactions and chemical arithmetic which few operating engineers have. This part should be entrusted to a chemist who has specialized in water purification. A mistake in the proportions could easily cause much waste and dam- age. In general, a compound will be the most effective when the water in the boiler is in good circulation. The use of boiler compounds requires the frequent use of the blow-off valve. 34 SIMPLE WATER TESTING. CHAPTER V. Regulation and Purification. Defects of Boiler Compounds. Under the heading of “ Boiler Compounds/' it was pointed out that one compound having the reagents in a fixed proportion could not be a cure for every boiler. Again, the same compound would not be as effective with a given boiler at all times of the year because the proportion of the impurities in the water varies. To be effective it is necessary that the compound used should contain the reagents in the proper proportion; and, then, that the compound should be used in the proper proportions. Even then the use of a compound can not be entirely satisfactory. Since the compound is applied to the water in the boiler the total impurities in the boiler water are increased. The constant evapora- tion of the water leaves the old compound as well as the original impurities in the boiler. While a boiler compound will prevent the formation of hard scale to a large extent, and, although most ready-made mixtures will prevent corrosion, it must be remembered that the resulting sludge must be frequently removed from the boiler or the good results are lost. Of course, boiler compounds containing such ingredients as potatoes, corn, leather, manure, and similar starchy or gelatinous matter, as well as those containing organic acids, should be avoided. If the plant is a small one and it is decided to try a ready-made compound the maker should be required to say what the compound contains, or, at least, certify that it is free from starchy, gelatinous and acid SIMPLE WATER TESTING. 35 matter. Ready-made compounds are not to be com- mended. Softening and Purification Tank Systems. The softening and purification tank systems are, perhaps, the most satisfactory method of treating feed- waters which have so far been devised. Their action is chemical; but, unlike boiler compounds, the water is treated before it reaches the feed-water heaters and boilers. In these systems the water is freed from its soluble impurities by chemical precipitation, and the corrosive acids neutralized before the water enters the steam plant. There are two classes of tank systems which are used. These are called the continuous and the intermittent, respectively. In each case the proper proportion of reagents is prepared by mechanical mixers and then introduced into the feed-water in large treating tanks. In the continuous system the reagents are introduced into the water in proportion to the flow of the water. The quantity of the reagents introduced into the water must be changed to meet the variations in the water. In the intermittent system, a definite quantity of water is treated with an exact quantity of reagents, time being allowed for sedimentation. In some intermittent systems the reagents are introduced as in the continuous system, but while the water is treated in one tank, it flows into a settling tank or tanks and the process is carried on alternately. The inter- mittent method permits accurate treatment regardless of the variations in the source of supply or the varia- tions in the rate at which the treated water is used. The continuous method, on the other hand, is affected by variations in both the supply and the quantity re- quired, and when wide variations occur, accurate treat- ment is not possible. Since only accurate treatment can give the best results, the intermittent system is to be preferred. By the use of a good tank system all Fig. io. THE WE-FU-GO SYSTEM — INTERMITTENT. SIMPLE WATER TESTING. 37 corrosive matter is removed and the quantity of scale- forming impurities in the water is reduced to the min- imum. It is practically impossible to remove all the soluble impurities from the water because even calcium carbonate and magnesium hydrate, which are the prod- ucts of the chemical treatment, are slightly soluble. The sodium salts which result are soluble ; and, since they are introduced to effect the removal of the other impurities, they are always present in treated water. No further chemical treatment can remove the sodium salts. Fortunately, sodium salts in such minute quan- tities as are present in a properly treated water are harmless to a boiler. The Intermittent System. A good type of intermittent tank apparatus is shown in Fig. 10 and two of the various methods of installation are shown in the diagrams, Figs. 11 and 12. The essen- tial parts are two treating and settling tanks, having power-operated stirring devices, and a jet or pump for 38 SIMPLE WATER TESTING. THE WE-FU-GO SYSTEM — WITH PUMP SUPPLYING OPEN HEATER. introducing reagents into the treating tanks.' A filter is included when necessary. In this apparatus the treating tanks are alternately filled with the water. The reagents are introduced while a tank is. filling and the solution is thoroughly mixed by the rotating paddle. The paddle is operated by power from a line shaft or other source. The revolv- ing paddle also stirs up the old sludge, which floats about in the water and hastens the action. When the tank is full, the paddle is stopped and the water left to stand so that the precipitate can settle to the bottom.' The softened water is drawn off from the top by means of a hinged floating outlet pipe. The water then passes through the filter beds, when necessary, to remove any sludge which may be carried along. During the time that one tank is filled, treated and settled, the other is used to supply the treated water, so that when one is empty the other is ready for use. This method insures a steady supply of clear softened water. In the bottom of the tanks there are pipe connections SIMPLE WATER TESTING. 39 for filling and washing the tanks. The tanks have to be washed out about once each week when in use. This is done by opening the valves to the sewer and starting the paddle which stirs up the sludge. The soft sludge then runs out. The Continuous System. One of the several types of continuous apparatus is shown in Figs. 13 to 16. This particular apparatus is called the tower type. It consists of a tower tank which has separate compartments for the lime and soda re- actions and for settling, and mechanical stirring paddles in the reaction compartments. With the tower tank there are provided lime and soda solution tanks with mechanical paddles, a pump for forcing the solutions into the compartments, a motor or engine to operate the paddles and pumps, and a gravity or pressure filter. The apparatus is automatic and continuous in opera- tion. The quantity of the reagent introduced into the water is regulated by the quantity of the water which flows through the apparatus. The speed of the pumps is regulated by the amount of water which comes into the apparatus and in turn the quantity of the reagents which are pumped into the water is regulated by the pumps. The water enters the tank from the bottom and passes into the first compartment, where it is treated with one reagent, and then enters the second compart- ment, where it is treated with another reagent. As in the intermittent type previously described, the revolv- ing paddles mix the reagent with the water and the old sludge helps to hasten the precipitation. The water then passes up into the third and top compartment which acts as a settling tank. This top compartment is sometimes made large enough so that it can be used for storing the treated water. The treated water is drawn off through a floating outlet pipe, which also SIMPLE WATER TESTING. Fig. 13. THE CONTINUOUS SYSTEM — TOWER TYPE. SIMPLE WATER TESTING. 41 Fig. 14. THE CONTINUOUS-TOWER TYPE SYSTEM. With treated -water storage in treating tank outside of building. With low- pressure filters and operating apparatus inside of building. THE CONTINUOUS-TOWER TYPE SYSTEM. With gravity filters supplying boiler-feed pump. 42 SIMPLE WATER TESTING. THE CONTINUOUS-TOWER TYPE SYSTEM. With gravity flow to open heater. acts as a regulator for the water which enters the tower, and the water passes through filters before reaching the steam plant. These systems are generally installed outside of the steam plant and in large installations they form .a separate plant in themselves. There are various mod- ifications of the continuous and intermittent types which have been described, each having its own merits, but the general scheme in each case is the same. There is one other type of apparatus which is used inside the steam plant and which treats the hot water under pressure as it comes from the heaters. (See Figs. 17 and 18.) It is very compact. The water is treated under pressure at a temperature of 175° F., or more, and the chemical action is very fast. The precipitate is removed by filters and by blowing it out from the precipitating tanks. In all of the systems the complete SIMPLE WATER TESTING. 43 Fig. i 7. THE SCAIFE SYSTEM. 44 SIMPLE WATER TESTING. THE SCAIFE SYSTEM — WITH CLOSED HEATER. SIMPLE WATER TESTING. 45 action of the reagents on the water is accomplished and the treated water is very satisfactory for steam plants. The systems which have been described require some attention daily. They can be cared for by an engineer or fireman without affecting his other work. Tests have to be made from time to time and the pro- portion of the reagents changed to meet the varying conditions. Since there is considerable chance for error if this is not carefully done, the efficiency of the system depends upon the operator to a large extent. The Cost of Softening and Purification. The exact cost of softening and purifying a feed- water varies in nearly every case. It is evident that a water containing a lime content of thirty grains will cost more to soften and purify than a water having a lime content of 15 grains. Besides the original invest- ment, the various savings effected must be considered in considering the cost of a softening plant. Roughly the investment will come to $5 for each horse-power for small plants up to 500 H.-P; $4 for each horse- power in plants of 500 to 800 H.-P. ; $3.50 per H.-P. for plants of 800 to 1,250 H.-P; and for plants of 1,300 to 6,000 H.-P., or larger, the cost will amount to $3 to $1.50 per H.-P. In Fig. 19 some figures are given which give a good idea of the savings which result from treated water. They were compiled by Mr. J. C. Wm. Greth. The plant was a 450 H.-P. one, and the saving in coal, which would amount to about one per cent, was not considered, because the plant was operated at a coal mine. Regulation and Purification. Filtration. — Whenever the feed-water is muddy or if it contains suspended matter, it must be filtered be- fore it is used. When any of the tank systems just 46 SIMPLE WATER TESTING. Operating with Well Water. Boiler repairs, new tubes, and labor $1,450.00 Cleaning boilers, two days each week, 52 cleanings a year, 104 days at $1.60 each 166.40 Cleaning heater twice a week (soda ash used in heater), 5 hours each cleaning, 52 days’ labor at $1.60 83.20 Soda ash, 30,000 lb. at 1 cent per lb * 300.00 $1,999.60 Operating with Water-Softening .System- Treating Well Water, Boiler repair^ (three new tubes)... $111.00 Cleaning each boiler, 4 boilers, 4 times a year, 2 days each cleaning, 32 days at $1.60 per day 51.20 Cost of treating water (about 4 cents per thousand gallons) 531.36 Depreciation at 10 per cent on investment of $1,900..^ 190.00 Interest at 6 per cent on investment of $1,900 .’ 114.00 997-56 Savings effected $1,002.04 Almost 53 per cent on an investment of $1,900.00. Well Water. Raw. Grs. per U. S. Gallon. Volatile and Organic Matter.. 1.85 Silica 1 °5 Oxides of Iron and Alumina., trace Calcium Sulphate 3060 Magnesium Carbonate H-34 Magnesium Sulphate 2.15 Sodium Sulphate 4-39 Sodium Chloride i.8r Total Solids 53- T 9 Suspended Matter 10 Free Carbonic Acid 55 Incrusting Substances 46.99 Treated. Grs. per U. S. Gallon. Volatile and Organic Matter.. .55 Silica 12 Oxides of Iron and Alumina., trace Calcium Carbonate 2.11 Magnesium Carbonate 51 Magnesium Hydrate 70 Sodium Carbonate 13 Sodium Sulphate 3878 Sodium Chloride 180 Total Solids 4470 Incrusting Substances 3.99 SIMPLE WATER TESTING. 47 described are used, a filter is generally included to re- move any sludge which remains after the water leaves the settling compartment. The feed-water should always be free from suspended matter as well as the soluble impurities as far as is possible, before entering the steam plant. The principle of the sand filter is understood by most of the readers without doubt. A good type of filter with a few novel features is shown in Fig. 20. Fig. 20. In this type of filter a coagulent such as aluminum sulphate is used. A comparatively high rate of flow is obtained. 48 SIMPLE WATER TESTING. A good filter should remove all of the suspended matter, but it should be remembered that no filter can remove the soluble dissolved matter. The Surface Blow-off.— This boiler attachment is not a water purifier, but it is mentioned because it is useful in connection with the methods of treating water. Its service is limited to the removal of the impurities which gather at the water line in a boiler. It is invaluable in plants where boiler compounds are resorted to. By frequent blowing, the impurities, which concentrate in the boiler from evaporation, can be reduced to a considerable extent. Chemical Feed-water Heaters. — The chemical feed- water heater has been tried with a little success. In- stead of putting the reagent mixture in the boiler it is introduced into the heater. A filter is used to separate the resulting precipitate. The chief defect of this method is that it does not remove all of the impurities, and although it appears better than putting compounds into the boiler, enough impurities pass into the boiler to form scale in spite of this treatment. Other Purification Systems. — There are many other systems which aim to treat the water so as to purify it for steam purposes. The Patent Office records contain a long list of these attempts. Some appear to be good, others are workable, and still others are absolutely useless. Almost everything seems to have been tried, including mechanical, electrical and chemical methods. The perfect and inexpensive water purifier remains to be invented. It must be cheap, automatic, reliable and furnish pure water. Finally. — It is hoped that this short treatise has pointed out the importance of good feed-water; how the impurities in a given supply can be determined in a simple manner with a fair degree of accuracy; and how a water supply can be regulated and purified for steam purposes. ALPHABETICAL INDEX. PAGE Acids 24 Acid Test, The 15 Acid Waters 18 Boiler Compounds 32 Boiler Precipitates 25 Calcium 20 Calcium Chlorid 27 Carbonates 25 Carbonate of Iron 20-28 Carbonate of Magnesia 28 Chemical Feed-water Heaters 48 Chemical Regents 31 Chlorid of Magnesium 28 Continuous System, The 39 Cost of Softening and Purification, The 45 Defects of Boiler Compounds 34 Delicate Test, A 20 Determination of Hardness 8 Dissolved Mineral Salts 25 Effects of the Impurities 24 Feed-water 3 Filtration 45 Hardness 7 Intermittent System, The 37 Iron Test 20 Lake Water 3 Lime Water 10 50 SIMPLE WATER TESTING. PAGE Method 9 Methyl Orange 15 Nitrate of Lime 28 Occurrence of Water in Nature 1 Operation, The 11 Organic Acid 24 Organic Matter 24 Other Purification Systems 48 Permissible Hardness 16 Purification of Water, The 30 Regulation and Purification 22 Remarks 13 Silicia 28 Soap Test, The 8 Softening and Purification Tank Systems 35 Source of Water 1 Standard Sulphuric Acid 10 Sulphate of Lime 25 Sulphate of Magnesia 28 Supply from Rivers 3 Surface Blow-off, The 48 Test for Chlorids, The 18 Test for Sulphates, The 18 Testing, The 5 Chemistry for the Engineer, the Electrician and the Operating Man By CHARLES A. WATKINS, Ph.D. This book is written for the practical oper- ating man, because it deals with the subject in such a manner as to give valuable knowledge in reference to such chem- istry as is of especial use to engineers, elec- tricians, etc., in every- day life. Among the subjects treated in this work are: The Air: Its Value in the Development of Chemistry. The Air: Its Constituents and Their Functions. Water: Its Composition and One of Its Constituents. Water as a Natural Substance. The Chemical Equation. Carbon : The Element. The Heating Value of Fuel : General Principles. Technology of Fuels. Solid Prepared Fuels. Liquid Fuels. Gaseous Fuels. Coal Gases. Water Gases. Producer Gases. Chemical Formulations and Calculations. The Combustion of Coal under the Boiler. Flue Gas. The Analysis of Flue Gas. Heat Losses in Combustion. Heat Losses in Flue Gas. Other Heat Losses. Chemical Talks, etc. Handsomely bound in cloth, printed in large type, on good paper and fully illustrated. Price, postpaid $1.50 One Thousand Questions and Answers for Engineers, Applicants for License and Electricians By JOSEPH G. BRANCH, former Member of the Board of Examining Engineers of the City of St. Louis, Editor “Practical Electricity and Engineering.” This book contains questions with answers, asked by Examining Boards for'engineer’s license, and for electrician’s card, and alfeo questions and answers covering the entire field of steam engin- eering and practical electricity, including wiring diagrams. It is a complete library in one volume, and one that no progressive engineer, electrician, fire- man, dynamo tender, or student can afford not to have with him at all times, or within reach. The book is printed in large type, fully il- lustrated, 180 pages, 5^x7 V 2 inches, and is strictly up to date. If you wish immediate delivery you must write today as the first edition is already about sold. The Electric Motor and Its Practical Operation By ELMER E. BURNS The only book giving a simple, clear and up-to-date explanation of the principles and opera- tion of all kinds of electric motors. CONTENTS Chapter I. — How an Electric Current Can Produce Motion. Chapter II. — The Beginning and Growth of the Electric Motor. Chapter III. — Power and Efficiency of a Motor. Chapter IV. — Counter-electromotive force. Chapter V. — How Power is Lost in a Motor. Chapter VI. — Armatures and Cummutators. Chapter VII. — Types of Direct-current Motors. Chapter VIII. — Starting Boxes and Their Connections. Chapter IX. — Curve Tracing. Chapter X. — How to Understand Alternating-current Motors. Chapter XI. — Operation of Alternating Current Motors. Chapter XII. — Speed Control of Motors. Chapter XIII. — Motor Troubles and How to Cure Them. Chapter XIV. — Selecting and Installing Motors. Appendix. — Horse-power Required to DriveVarious Machines. Size 5^x7^ inches; 200 pages; fully illustrated. The Joseph G. Branch Publishing Company 608 South Dearborn St., CHICAGO, ILL. Price, $1.50, Postpaid.