Zbi6 IDolume IS AFFECTIONATELY DEDICATED TO MY MOTHER. PREFACE. The manufacture of glafe-s being essentially an industry requir- ing chemical operation, it is apparent that its successful prosecu- tion requires some knowledge of ehemistry. This fact, however, has not been given the attention it deserves. The skill of the glassmaker heretofore has been dependent on his knowledge of formulae and recipes, and on his experience with them which en- abled him to forecast results without aetually knowing the reasons for these results. When unfavorable they were attributed to bad luck," while as a matter of fact, bad luck was probably due to imperfections in the ingredients used in the batch, which with a little chemical knowdedge could have been detected in time to avoid failure in the melt. Most glassmakers are at the mercy of those who supply the chemicals, and although competition has considerably raised the standards of purity there is room for improvement. Besides the testing of raw materials there are operations which should be subjected to chemical scrutiny, such as batch-mixing, gas-making, etc. This is best performed by constant, routine analysis, which will be found very valuable in the long run, be- sides exerting a salutary effect on the workmen. This book is written for those who have not had the advantage of a training in chemistry, but who while engaged in glassmaking have felt the necessit}' of scientific supervision of their work. It is a difficult matter to instruct in chemical analysis one who has had no previous chemical knowledge, and although this book is written in as simple language as possible, it is desirable that the reader, if not a chemist, should obtain practical instruction from some trained operator. This applies particularly to Part III, General Procedure of Analysis, in which the manipulations are difficult to describe with justice, but are quite simple when actu- ally performed. (V) vi PREFACE. Most of the methods of analysis given are from the author's actual experience, the others are those commonly used by chem- ■ lets. I am indebted to Dr. Arthur H. Elliott for many sugges- tions, for several of the methods, and for much kind assistance. CONTENTS. PART I. Chemical Theory 1 PART II. The Metric System 3 PART III. General Procedure of Analysis 5 PART IV. Volumetric Analysis ....... 30 PART V. Reagents 40 PART VI. Methods of Analysis 53 APPENDIX. Specific Gravity ; Tables; The Care of Platinum Vessels. 116 INDEX 131 ( vii ) PART I. » CHEMICAL THEORY. In order to properly understand the various operations of Chem- ical Analysis, a short description of Chemical Theory will be necessary. The smallest sub-division into which a body can be divided without its undergoing a chemical change, is called a molecule. The smallest particle of a body which can exist in chemical com- bination is called an atom. Any substance which cannot be divided into other substances having different chemical characteristics is called an elementary sub- stance or element. A substance which can be so divided is called a compound. The atoms which compose an element have the same nature, while those which make up a compound may be of two or more different natures. As an example, we have the metal Iron. No matter how finely we divide a mass of Iron, the sub-division will still be Iron, and have all the properties of that metal. On the other hand, we have common iron rust, which is a combination of Iron with Oxygen, or an Oxide of Iron. We can by chemical means separate the Iron from the Oxygen, thus obtaining two sub- stances, one of Avhich is a metal, and the other a gas. Atoms combine with each other to form molecules. These com- binations take place according to certain rules and in definite pro- portions. For example, the gas Oxygen combines with the gas Hydrogen to form Water. These gases combine in the proportion of one atom of Oxygen to two atoms of Hydrogen, thus forming one molecule of water. If we have a compound, and wish to determine the proportion of a certain constituent, we proceed to separate that constituent from the compound, that is, we cause it to assume some form by which it may be isolated, and measured or weighed. Take, for example, a mixture of water and Hydrochloric Acid in which we wish to (1) 2 CHEMICAL ANALYSIS FOR GLASSMAKERS. ascertain the amount of Chlorine. We add to the mixture a solution of Silver Nitrate in water. The Chlorine will combine with the Silver, forming Silver Chloride, which will separate and may be weighed, and from its weight the Chlorine may be calculated. In Chemistry the elements are designated by letters, generally the initials of their names. These letters are called symbols, and by means of these symbols we are able to write and explain in a graphic manner, the various chemical combinations of these ele- ments. The elements combine in the proportions of their atomic weights, that is, their weights as compared with that of Hydrogen gas taken as 1. For instance, the atomic weight of Oxygen is 16, or the weight of an atom of Oxygen is sixteen times that of an atom of Hydrogen. As two atoms of Hydrogen combine with one atom of Oxygen to form one molecule of water, we write: Hj + 0 = H20 two Hydrogen atoms plus one Oxygen atom form one molfcule of water. When one atom of an element combines with one atom of Hydrogen or its equivalent, that element is known as Monovalent. When one atom of an element combines with two atoms of a mon- ovalent element it is called Divalent; with three atoms, Trivalent, etc. The following will explain : HCl, here Chlorine (CI) is monovalent. HgO, here Oxygen (0) is divalent. NHg, here Nitrogen (N) is trivalent. This property of elements is termed Valence or Quantivalence, and represents their combining powers in relation to that of Hydrogen. Elements may possess different valences; for example: Chlorine (CI) in Hydrochloric Acid (HCl) is monovalent, while in Potas- sium Chlorate (KCIO3) it is pentavalent. Sulphur (S) in Hydrogen Sulphide (HgS) is divalent, while in Sulphur dioxide (SO2) it is tetravalent, and in Sulphur trioxide (SO3) it is hexavalent. PART II. THE METRIC SYSTEM. The weights and measures given in this book are of the Metric System. This system is used in all operations of chemical anal- ysis. Being entirely of decimal notation it is the most convenient that could be devised, and is coming into universal use even for the common purposes of life. It is the standard system of weights and measures in all civilized countries except the United States and the British possessions. Its fundamental unit is the Meter, which is the distance between two lines, at 0 degrees Centigrade, of a certain bar of platinum- iridium alloy kept at the Internationa] Bureau of Weights and Measures, near Paris, France, and is known as the International Meter. The meter is divided into ten equal parts, called decimeters (dm.), each decimeter into ten equal parts calleJ centimeters (cm.), each centimeter into ten equal parts axlled miUivieters (mm.). These divisions are expressed thus: 1 meter equals 10 decimeters or 100 centimeters, or 1000 miUimeters. Written decimally, 1 millimeter (1 mm.) equals .001 meter; 1 centimeter (1 cm.) equals .01 meter; 1 decimeter (1 dm.) equals .1 meter. The metric unit of volume or capacity is the Liter, which is the volume of the cube of one-tenth of the international meter. The liter is divided into ten equal parts called deciliters (dl.); the deci- liter into ten equal parts called centiliters (el.); the centiliter into ten equal parts called milliters (ml.), or cubic centimeters (c.c. ). These divisions are expressed thus: 1 Liter equals 10 deciliters, or 100 centiliters, or 1000 cubic centimeters. Written decimally, 1 cubic centimeter (1 c.c.) equals .001 liter; 1 centiliter (1 cl. ) equals .01 liter; 1 decihter (1 dl.) equals .1 liter. The unit of weight is the Gram which is the weight of j^^ins" P^^'t of a certain cylinder of platinum-iridium alloy kept at the Inter- national Bureau of Weights and Measures, near Paris, France, and (3) 4 CHEMICAL ANALYSIS FOR GLASSMAKERS. known as the International Kilogram. The gram is divided into ten equal parts called decigrams (dg.); the decigram into ten equal parts called centigrams (eg.); the centigram into ten equal parts called milligrams (mg.). These divisions are expressed thus: 1 gram equals 10 decigrams, or 100 centigrams, or 1000 milligrams. Written decimally: 1 milligram (1 mg.) equals .001 gram; 1 centi- gram (1 eg.) equals :01 gram; 1 decigram (1 dg.) equals .1 gram. The terms decimeter, deciliter, and decigram, are not generally employed. Units of length are expressed in meters, centimeters, and millimeters, units of volume in liters and cubic centimeters, units of weight in grams and milligrams. The following table gives a complete view of the Metric System, showing also the measures which are in excess of the Meter, Liter, and Gram: Meters. Names. Symbols. Liters. Names. Symbols, Grams. Names. Symbols. 10000 Myriameter Mm. 10000 Myrialiter Ml. 10000 Myriagram Mg. 1000 Kilometer Km. 1000 Kiloliter Kl. 1000 Kilogram Kg. 100 Hectometer Hm. 100 Hectoliter HI. 100 Hectogram Hg. 10 Dekameter Dm. 10 Dekaliter Dl. 10 Dekagram Dg- 1 Meter M. 1 Liter L. 1 Gram G. .1 decimeter dm. .1 deciliter dl. .1 decigram dg. .01 centimeter cm. .01 centiliter cl. .01 centigram eg- .001 millimeter mm. .001 milliliter ml. .001 milligram rag. Tables showing the comparative values of the Metric and U. S. Systems will be found in the Appendix. PART III. GENERAL PROCEDURE OF ANALYSIS. SAMPLING AND PREPARING THE SAMPLE FOR ANALYSIS. The object of sampling is to secure such a specimen of the ma- terial to be analyzed as will correctly represent the average quality. Figure 1 represents a convenient sampler or tool for sampling. It consists of a 2-inch brass tube a, about 18 inches long, fitted to a handle b. It has its surface cut away, giving the section c, and the end d is rounded or pointed. If the material to be sampled is in barrels, bags or receptacles of small bulk, the sampler is plunged into each package, and a sample withdrawn. If the contents of a batch barrow are sampled, d a t C portions are taken from various parts of the barrow. These differ- ent portions are thrown in a heap on a piece of rubber cloth about two feet square, and mixed by raising opposite sides of the cloth. When thoroughly mixed the heap is divided into four parts, by drawing a cross through it, with a large spatula. Two of the quarters are rejected, and the sides of the cloth are again raised, the material mixed, quartered as before, and the opposite quarters rejected again. The process is continued until only enough mater- ial remains to fill an 8-ounce, wide-mouth bottle, which is to be tightly stoppered. If the material is in lumps, it is pulverized before mixing and quartering. This is effected by means of a Mortar and Pestle. For substances like Coal, an Iron Mortar and pestle are used. (Fig. 2. ) For lumpy Soda Ash, Lime, and any substance which (5) 6 CHEMICAL ANALYSIS FOR GLASSMAKERS. is easily pulverized, and which does not cause wear on the mortar, a mortar and pestle of porcelain or wedgewood are employed. (Fig. 3..) When fine pulverization is necessary, an agate mortar and pestle are made use of. (Fig. 4. ) Agate pestles are usually of very short length, and inconvenient to grasp, therefore it is better to fit them into a wooden handle, cementing with a little glycerine and litharge rubbed together into a cream. It is well also to fit the mortar into a stationary wooden block, having a depression to hold it, of such a size as to permit its easy withdrawal for the pur- pose of emptying. If the substance is in very hard lumps, such as glass, minerals, etc., a steel mortar and pestle are employed. Figure 5 represents A this form. The parts a and h are fitted together. The material to be pulverized is placed in &, and the pestle c is pushed into h. The whole is then held firmly, and c is struck with a hammer, driving it into h. The mortar is then taken apart, and the con- tents placed on a clean china plate. A magnet is passed through the fragments to remove any particles of steel abraded from the mortar. The lumps and powder are then removed to an agate mortar for further pulverization. It is sometimes necessary to dry a powdered sample before weighing it for analysis. This is done by placing the powder in a porcelain dish (Fig. 47), and setting the dish on the shelf of a drying oven (Fig. 37), which is heated to 100° Centigrade. This operation, in individual instances, will be described in Methods of Analysis. If the substance is in a large shipment, such as a carload, a GENERAL PROCEDURE OF ANALYSIS. 7 number of barrels, etc., a sample is to be taken from every tenth barrel or bag, or at intervals while the car is being emptied, heaped together, and quartered down until it is small enough to be mixed on the rubber cloth as above described. Sampling must be performed with great care, and the fact must be borne in mind, that the sample is to represent the average quahty of the material to be tested, and that an analysis made of an unfair sample is utterly useless as far as practical purposes are concerned. Some substances, such as batches, are difficult to sample, owing to the different densities of their ingredients. These ingredients becoming separated instead of mixed by the movement, the heav- iest sinking to the bottom. It will be found that this trouble may be readily overcome by the use of the rubber cloth. Where special care is necessary in samphng certain materials, it will be described under the Method of Analysis, which is appli- cable in such cases. WEIGHING. The Balance and Weights. Figure 6 represents the ordinary form of Analytical Balance. The beam a is divided into spaces which represent milligrams and fractions when the rider r is placed thereon. The rider r is moved into position by means of the hooked rod h. When not in use the rider is always to be left suspended from the hook. 8 CHEMICAL ANALYSIS FOR GLASSMAKERS. A pair of watch glasses (Fig. 7) of equal weight are placed on the pans c and d. The material to be weighed is placed in the watch glass on the pan c, and the weights in the watch glass on the pan d. The beam a is raised and lowered by means of the screw and the balance finally ~~7 put into action by pressing the push but- ^ — """^ ton /, which lowers the pan supports gg. Ti^.T. When the balance is in equilibrium, the needle h swings over equal spaces on each side of the indicator I. Sometimes the needle refuses to move, and a gentle current of air must be applied to the pan by fanning with the hand. As the balance is a very delicate instrument, and the accuracy of every analysis depends largely on its condition, great care is re- quired in its use. It should never be subjected to any but the most deHcate handhng. The various parts must be kept free from dust by cleaning with a camel's hair brush, and keeping the door of the glass case closed when the instrument is not in use. No substance should be weighed without the intervention of the watch glasses. In setting up and adjusting, follow carefully the directions given by the maker. Do not subject the balance to any shock, and do not place it in any position where it will receive vibrations from the building. It is well to have the shelf on which it stands fastened to the wall, and not directly connected with the floor. A good way to avoid vibration is to support the levelling screws 1 1 on large rubber bottle-stoppers, having thin disks of metal to prevent the screws from sinking into the rubber. This will obvi- ate much of the vibration. Vibration interferes with the operation of weighing and impairs the sensibility of the balance. When using the screw e, turn it slowly. Each day before be- ginning work remove, with a camel's hair brush, all dust that may have settled on the beam and pans. Before weighing, see that the balance is correctly adjusted, thus: If the needle h does not point to the center of the indicator I, adjust it by means of the small screw which is on the pan-rest behind the pan d. Turn the screw e, and press the button /, and if the needle does not move over equal spaces of A;, release /, and turn back e, and then GENERAL PROCEDURE OF ANALYSIS. 9 turn the screws m m. Again turn e, and press /, and repeat the process until h moves over equal spaces on each side of k. It will be readily seen that the side of h which shows the greater number of spaces passed over by h is the lighter, and the object of the screws m m is to overcome this inequality of weight. Always have in the balance case a small wide-mouth glass ves- sel containing fused granular Calcium Chloride to assist in keep- ing the air dry, and preventing any moisture from condensing on the balance. This should be occasionally renewed. The weights used in chemical analysis are of the Metric system which has been described. (See pages 3 and 4. ) These weights are the gram, and its fractions and multi- ples. A convenient set of weights is shown in Figure 8. It has a range of from 50 grams to 5 milligrams, and contains the following: One of 50 grams, one of 20 grams, two of 10 grams, one of 5 grams, two of 2 grams, one of 1 gram, and also the following fractional weights: One of \ gram or 0.5 gram or 500 miUigrams. One of y\ gram or 0.2 gram or 200 milligrams. Two of gram or 0.1 gram or 100 milligrams. One of 2-V gram or 0.05 gram or 50 milligrams. One- of gram or 0.02 gram or 20 milligrams. Two of gram or 0.01 gram or 10 milligrams. One of gram or 0.005 gram or 5 milligrams. Weights lower than 5 milligrams are obtained by the use of the rider r on the balance beam. The beam is divided into spaces corresponding to 1 milHgram, which in turn, are subdivided into milligrams. The weights from 50 grams to 1 gram are made of brass, and the fractional weights from 500 milligrams to 5 milligrams of platinum foil. The sum of the weights used is expressed in grams and decimal fractions, as can be seen in the following example: 10 CHEMICAL ANALYSIS FOR GLASSMAKERS. One 20 One 10 One 2 gram weight, gram weight, gram weight. One 0.5 gram weight. One 0.2 gram weight. One 0.05 gram weight. 0.0034 gram as obtained by using the rider. Total weight 32. 7534 grams, or 32 grams, 753y\ milhgrams. Before replacing the weights in the box, check them by count- ing up from the vacant spaces, to see if the addition is correct. Each empty space represents a weight taken out and used, and the sum represented by such spaces should correspond to the sum of the weights on the balance pan. Each weight is to be returned to its proper place in the set, and the set must be kept covered Avhen not in use. The weights should never be touched or handled with the bare fingers, but always with the pincers which are provided for this purpose. Always keep the set in a place where it will not be affected by acid fumes. A good place is within the balance case. If the weights become tarnished, do not attempt to brighten them. The crust or film which may form is too slight to seriously affect accuracy. When dusty they may be cleaned with a camel's hair brush. The weights should be accurately adjusted, that is, they must be correct multiples; for example, the 20 gram weight must be just twice the 10 gram, and twenty times the 1 gram weight, and so on. This point is really of more importance than the abso- lute accuracy of the weights themselves. As every analysis depends for its correctness on the quality of the balance and weights, care should be taken to purchase only of a maker of known reputation. It is a very poor plan to sacrifice quality for cheapness in this respect. Weighing out a portion of the Sample for Analysis. There are two methods of procedure, namely: I. By direct weighing. II. Weighing by difference. Direct Weighing. Place on the watch glass d (Fig. 6) the weight GENERAL PROCEDURE OF ANALYSIS. 11 of the denomination desired, and on the watch glass c some of the sample, pouring it from the vial or bottle, or using a three-inch spatula (Fig. 9). Turn the screw e, and press the button /. If the needle h moves towards the right, release / and turn back e, and remove some of the sample from the watch grass. If on the other hand, h moves to the left, add a httle more of the sample. Continue thus until h moves over the same number of spaces on either side of h. The watch glass c is then taken from the bal- ance pan and emptied into a convenient receptacle for further treatment. The last portions of the weighed sample are brushed into the same receptacle with a camel's hair brush. The watch glass is then replaced on the balance pan. Weighing by difference. This method is used when the sample c is a liquid, or a solid which absorbs moisture when exposed to the air. The sample should be in a glass vial, which has a flat bottom (Fig. 10), and is closed with a cork or glass stopper. Place the vial upright on the watch glass c, and on d sufficient weights to balance it. Remove the vial, take out the stopper, and pour out a portion of the sample into a convenient vessel. Stopper the vial and replace it on the watch glass. From d re- move sufficient weights to again balance the vial and contents. The weights removed will represent the weight of the sample taken for analysis. Example of weighing by difference: Weight of the vial and contents .... 25.0392 grams. Weight after removal of part of the contents 24.0392 grams. Weight taken for analysis 1.0000 grams. 12 CHEMICAL ANALYSIS FOR GLASSMAKERS. SOLUTION. The next step is to bring the weighed sample into solution. A substance is in solution when it is so diffused through a liquid that its previous form is not apparent to the eye. The liquid is called the solvent, and the combination of the body with the solvent is called the solution. The solution is named from the material dissolved. A familiar example is that of common salt and water. When salt is placed in water it dissolves or goes into solution, and we have a solution of salt. A substance which dissolves readily is said to be soluble. When the solvent has no effect on it, it is said to be insoluble. When a liquid has dissolved all of the substance that it can, we have a saturated solution. There are three conditions to be noted, viz: I. The substance may be soluble. II. It may be insoluble. III. It may be partially soluble. I. The Substance is Soluble. The weighed sample being in a suitable vessel, as a beaker (Fig. 11), or a flask (Fig. 12), the solvent liquid is poured in, and if necessary, the vessel is placed on a tripod (Fig. 13), or a ring stand (Fig. 14), and gently heated by a Bunsen burner (Fig. 15). It is well t<^ interpose a piece of wire gauze between the bottom of the vessel and the flame of the burner. The heat- ing is continued until the sample is dissolved. If effervescence or giving-off of gas is noticed, the beaker should be covered by a watch glass (Fig. 7). When the sample is dissolved the watch GENERAL PROCEDURE OF ANALYSIS. 13 glass is removed, and its convex surface washed with a jet of hoi water, by means of a wash bottle (Fig. 20). The washings oi drippings should be allowed to run into the beaker. The use of the wash bottle will be considered in detail under Filtering. II. The Substance is Insoluble. The weighed sample on the watch glass c (Fig. 6), is removed to a larger watch glass, and mixed with the proper weight of a suitable flux. This mixture is placed in a platinum crucible (Fig. 16), and the crucible heated by a Bunsen burner (Fig. 15), or a blast lamp (Fig. 17), until the contents are in a fused state. When cool, the fused mass may be dissolved. This will be de- scribed in detail under Methods of Analysis. III. The Substance is Partially Soluble. The weighed sample is treated in a beaker (Fig. 11) with the solvent liquid, as described under I, the insoluble portion is fil- tered off (see Filtering), and the filter-paper and contents is heated in a platinum crucible. When the paper has been reduced to ashes, the residue is mixed with a flux, fused, cooled, dissolved, and the second solution added to the first. PRECIPITATION. When we have a solution containing an element or compound, which we wish to separate from that solution, we resort to Precipi- tation, and for this purpose we employ what is known as a Reagent. The term Reagent is applied to any substance, which when placed in contact with another substance, produces some chemical 14 CHEMICAL ANALYSIS FOR GLASSMAKERS. change or reaction. This is best illustrated by an example. We have, for instance, a solution containing Silver Nitrate (AgNOg). We wish to separate the Silver in some form so that it may be easily weighed. To this solution we add another of Salt or Sodium Chloride (NaCl). The Sodium Chloride reacts with the Silver Nitrate, causing a chemical change or reaction. The Silver com- bines with the Chlorine (CI) and forms Silver Chloride (AgCl), which being insoluble in the surrounding liquid, is deposited or precipitated. The reaction is written in chemical terms thus: AgNOg +NaCl =AgCl + NaNOg. Silver Nitrate + Sodium Chloride = Silver Chloride + Sodium Nitrate. By this means we isolate the Silver Chloride, and can filter it off for further treatment. In precipitation, the substance which is precipitated is called the Precipitate, and the reagent which causes the precipitate to form is called the Precipitant. Precipitates are of different natures, and require different treat- ment. They can be flocculent, when the precipitate floats about in the form of flocks or small clouds. Granular, when they are in the form of grains. Gelatinous, when they have the appearance of a jelly. Pulverulent, when resembling a fine powder. Crystalline. when deposited in definite shapes or crystals. The treatment of the different forms of precipitates will be ex- plained in detail under Methods of Analysis. FILTRATIOjy OR FILTERING. To separate a precipitate from a liquid, we filter it, and for this purpose make use of some medium which allows the liquid to pass through it, but retains the precipitate. The best medium is a specially prepared paper known as Filter Paper. This paper is made in two qualities, depending on the nature of the operation. They are. Quantitative filter-paper, which is used when it is neces- sary to preserve the precipitate for further examination, and Qual- itative, or Common filter-paper, which is employed when the liquid only is to be further investigated, or when the operation is one in which the presence of the substances and not their propor- tions are sought. GENERAL PROCEDURE OF ANALYSIS. 15 In connection with the filter-paper we use also a funnel, which is of glass, having the cone (a, Fig. 18) made at an angle of ex- actly 60°, and the stem (6) quite long, and ground to a point. It is important that the paper be folded to properly fit the funnel. Fig. 19 shows how this is to be done. Fold the paper in half along the diameter a, then again along the radius b. Open the paper in the form of a cone c, having one thickness at d and two at e. The paper is then placed in the funnel, and pushed down well. While still held by the fingers, the paper is wetted with a jet of water from the wash bottle (Fig. 20). The paper will cling to the funnel, and should be pressed closely to the glass to drive out any bubbles of air. If the funnel is correctly made, the paper will be close to the sides, and the water will run through rapidly. Always select a filter-paper of the correct size for the funnel used. It should extend to about an eighth of an inch below the funnel edge. Figure 21 shows the ap-pearance of the paper in the funnel, the cut a is the correct way, while b and c are wrong. The dotted curve shows the upper edge of the paper. 16 CHEMICAL ANALYSIS FOR GLASSMAKERS. The funnel is then placed in a filter stand (Figs. 22 and 23), the end of the stem being in contact with the inner side of the xz CM glass vessel placed beneath. Hold in one hand the beaker con- taining the liquid to be filtered, and with the other hold a glass rod against the hp of the beaker (Fig. 24). ^ \\ Incline the beaker and allow the liquid to V"-----^ gently down the rod into the funnel, at the same time keeping as much of the pre- cipitate as possible in the beaker. Allow the hquid to come to about a quarter of an inch below the edge of the paper, and then stop pouring until the funnel becomes nearly empty. Then continue pouring as before. The object of the glass rod is to prevent loss of liquid or precipitate by running down the outside of the beaker, and also to direct the flow so the liquid will not splash into the ■funnel. Never allow the liquid to rise over the edge of the filter-paper. When the liquid has all run through the paper, and the beaker is empty, direct a jet of water from the wash bottle (Fig. 20) on to the inside of the beaker. Pour into the funnel as before. Allow the funnel to entirely empty, and wash out the beaker as GENERAL PROCEDURE OF ANALYSIS. 17 shown in Figure 25, directing the jet of water so as to wash all the loose precipitate into the funnel. If any precipitate adheres to the beaker or rod, remove it with the aid of another glass rod which has a piece of pure rubber tubing on the end (Fig. 26). This second rod is called a policeman^ and is used thus: Wet the rubber with a jet of water, and clean the original glass rod by rub- Fi^ 25 bing it with the policeman, at the same time holding it over the beaker. When the precipitate has been loosened, place the police- man in the beaker, and wash off the rod into the beaker with a jet of water. Then lay this rod aside. Rub the inside of the beaker with the ])oliceman, and wash down the loosened precipitate from the sides and bottom. Hold the policeman against the lip, and pour into the funnel. Now direct a jet of water inside the beaker as shown in Fig. 25, washing 2 18 CHEMICAL ANALYSIS FOR GLASSMAKERS. the remaining precipitate into the funnel. Wash off the rubber tip of the poHceman, allowing the washings to run also into the funnel. When the funnel again becomes empty, gently direct a jet of water into it, turning the funnel at the same time, so as to wash the precipitate together into the bottom. Care should be taken to t 1 have the jet enter the funnel as gently as possible to avoid splash- ing, as this may cause loss of precipitate. Also begin washing at the edge of the paper, and gradually proceed downward. After each application of the wash water, allow the funnel to become entirely empty before resuming. It is important to wash the precipitate thoroughly. The means of determining w^hen thin is properly performed will be given under Methods of Analysis. Fi gures 27 and 28 show different kinds of wash bottles. Figure 28 is provided with a piece of rubber tubing r, to facilitate the directing of the jet. To use the wash bottle grasp it by the neck and blow into a ; a stream of water is forced out at b. When using the flexible tip (Fig. 28), the jet is directed by the forefinger held against the tip r. When a larger stream of water is desired, the bottle is held as in Figure 29, and the water allowed to flow from a. When hot GENERAL PROCEDURE OF ANALYSIS. 19 water is used the neck of the wash-bottle is wrapped with cork, sheet asbestos or heavy string to protect the hand. Terms used in Filtering. The precipitate remaining on the filter paper is sometimes called the filter. The Hquid which runs through the paper is called the filtrate. The liquid which runs through when the filter is washed is called the ivashings. When a precipitate is so fine as to run through the paper along with the filtrate, it should be filtered through two papers placed one within the other. This will retain most precipitates, but in some cases it may be necessary to pour the filtrate through the paper a second time. Filtering by Pressure. Some precipitates, owing to their gelatinous nature, prevent the liquid from passing freely through the paper, and pressure must be used to facilitate the operation. A cone of platinum foil, pierced with holes (Fig. 30), is placed in the funnel. The paper is folded (Fig. 19) and inserted also in Ti«.3o ■Fio,3I. the funnel. The cone prevents the paper from breaking or tearing when pressure is applied. The stem of the funnel is pushed through the hole of a rubber stopper which is inserted in the neck of a filtering flask of heavy glass (Figs. 31 and 31 A). A rubber tube is attached to the side tube a and connected with an exhaust- ing apparatus. The air drawn through a produces a vacuum in 20 CHEMICAL ANALYSIS FOR GLASSMAKERS. the flask, and consequently a pressure in the funnel, thus causing the liquid to pass rapidly through the paper. For some purposes a Gooch crucible is used. Figure 32 shows this form. It is made of platinum, and is in three parts. The part a has the bottom perforated for filtering. The cover h and the cap c are placed on the part a when the crucible is to be heated. When this crucible is used, the part a is inserted in a piece of soft rubber tubing as shown in Figure 33 d, and this tubing stretched over a piece of glass tubing e, which enters the stopper of the filter- ing flask. Some fine ignited asbestos is mixed with water and poured into a while the pressure is turned on. It packs into a pad or felt on the bottom of a, and the crucible is ready for filtering. When the operation is finished, the crucible is removed from the rubber tube, the cap" and cover put on, and the contents further treated as required. To obtain the necessary vacuum we may employ any of the apparatus shown in Figures 34, 35 and 36. Figure 34 shows a simple contrivance for exhausting. The bottle b is provided with an outlet c to allow the water to escape. This draws the air through a and produces the necessary vacuum. The flow of water from c is regulated by the screw compressor m which closes the rubber tube t. Figure 35 represents a glass filter pump. The tube a is con- nected with the filter flask by means of a piece of rubber tubing. Another rubber tube at 6 connects the pump with, a hydrant. GENERAL PROCEDURE OF ANALYSIS. 21 When the water is turned on it is forced in a jet through the crooked part c, drawing the air through a. Figure 36 is the same apparatus made of brass, being preferable on account of not being easily broken. The quahty of the filter-paper used in chemical analysis is im- portant. When the precipitate is to be ignited and weighed, care must be taken to use a paper which has the least possible weight of ash. There are excellent filter-papers on the market of both German and Swedish make, and while the former is the most advertised, it will be found in the long run that the Swedish is the most uniform in quahty. That sold under the name of Munck- tell's Swedish Filter-Paper is perhaps the best for general use, and is of reasonable cost. When selecting a piece of filter-paper to fit a certain size funnel, always see that the diameter of the paper is a httle smaller than twice the diameter of the funnel. 22 CHEMICAL ANALYSIS FOR GLASSMAKERS. Drying^ Igniting, and Weighing the Precipitate. After the precipitate is thoroughly washed, it is removed with the funnel to a drying oven (Fig. 37). This consists of a copper box with a sheet iron bottom, supported on iron legs and heated by means of a Bunsen burner placed beneath. The oven has two openings in the top, and a smaller one in one of the sides near the bottom. The lower opening and one of the upper ones are to ven- tilate the oven, and the other upper opening for the insertion of a thermometer, which is held in place by passing it through a cork. The thermometer should read to 200° Centigrade. The oven is closed by a hinged door, and has a shelf pierced with holes to support funnels. The funnel is covered by a watch glass or another piece of filter- paper wrapped over it to exclude dirt, etc. , and placed in one of the holes of the shelf. The oven door is closed, and the heat GENERAL PROCEDURE OF ANALYSIS. 23 regulated so that the thermometer does not show over 100° C. When the filter-paper and precipitate are dry, the funnel is taken out of the oven, the filter-paper removed, and the precipitate allowed to fall on a small watch glass, a sheet of clean writing paper, or on a sheet of black glazed paper which is sold for this purpose. A platinum or porcelain crucible with a cover is gently heated by being held with the crucible tongs (Fig. 38) in the flame of a Bunsen burner, and when hot placed in a dessicator (Fig. 39). Ti^.40. When cool, the crucible and cover are weighed on the Analytical Balance, and removed to the glazed paper on which the precipi- tate has been placed. The filter-paper is then rolled up length- wise, and held by wrapping round it a piece of platinum wire, which is fused into a glass tube (Fig. 40). The paper is ignited in the burner flame, and allowed to burn while being held over the open crucible; When nothing remains but a charred mass, it is gently detached, and falls into the crucible. The crucible and cover are placed on a clay triangle in an inclined position, and the 24 CHEMICAL ANALYSIS FOR GLASSMAKERS. burner flame adjusted to play gently against the cover, and be de- flected into the crucible (Fig. 41). When the paper is reduced to white ashes the burner is removed. When cool, the crucible is again placed on a sheet of glazed paper, and the precipitate brushed into it. Any particles that have fallen outside of the crucible are also brushed in, A camel' s- hair brush is used for this purpose. The crucible is then placed on the triangle in an upright posi- tion, and partly closed with the cover. A strong heat is applied with the burner. When the contents of the crucible are suffi- ciently ignited, it is removed together with the cover to the desic- cator, and when cool is weighed again. Example, Weight of crucible, cover and precipitate 26.9S63 grams. Weight of crucible and cover 26.6381 " Weight of precipitate .3482 " GENERAL PROCEDURE OF ANALYSIS. 25 Apparatus used in Igniting and Weighing the Precipitate. Figure 39 represents the usual form of desiccator. It is of heavy glass, having the under surface of the cover a ground to make a tight joint with the edge b which is also ground. The narrow part c supports a triangle of clay, or of platinum wire to hold the crucible. The lower part d contains lumps of fused granular Calcium Chloride, to keep the air in the vessel in a dried state. The object of the desiccator (meaning an apparatus for drying) is to insure the crucible being free from the film of moist- ure, which collects on all objects which are exposed to the air. This film, while not evident to the eye, may nevertheless, have an appreciable weight. The desiccator also serves to preserve some substances in the crucible from change due to the action of the air, as absorption of water or Carbonic Acid (COg)- Figure 16 (page 13) shows a platinum crucible. It may be used for igniting precipitates which are not liable to harm the platinum. It is free from the danger of breakage. It is the crucible always used in the analysis of silicates, where the sample must be brought into a fused state by means of a flux. With proper care, a platinum crucible will last a long time. (See re- marks on the care of platinum vessels. Appendix. ) Figure 42 shows a porcelain crucible and cover. Those of Royal Berlin Ware are the best. Porcelain crucibles may be used for nearly all ignitions. They are liable to break when suddenly heated, and the burner flame should be cautiously applied. Figure 38 shows how to hold a crucible when handling it with the tongs. The tongs are of nickel-plated brass, or of German silver, and sometimes have jaws of platinum. Figure 43 shows two forms of clay triangles or pipe-stem tri- angles. They are used with porcelain crucibles. For platinum crucibles, a platinum wire triangle is to be preferred which is shown in Figure 44. The triangle a of platinum wire is enclosed within a ring h of stout iron Avire. Figure 45 is a Bunsen burner. The gas enters at a, and mixes in the tube b with air which enters at the hole c. This mixture of air and gas passing up the tube b is burned at the top. The loose piece d is used to regulate the supply of air. When c is closed the gas burns with a luminous flame. When c is open the flame is blue and of a higher degree of heat. In igniting as described 26 CHEMICAL ANALYSIS FOR GLASSMAKERS. above, the blue flame should be used, as otherwise a film of carbon will be deposited on the crucible, also, if possible, do not allow the inner flame e to touch the crucible. connected with the gas supply and b with the air supply, obtained from a blower or foot bellows (Fig, 46). GENERAL PROCEDURE OF ANALYSIS. 27 EVAPORATION, Evaporation is the driving-off of a liquid in Avhich a substance is dissolved. It is usually conducted in an open vessel, such as a beaker, evaporating dish, or casserole. Beakers are of thin glass, and are shaped as shown in Figure 11. Evaporating dishes are made of porcelain or platinum. The best porcelain dishes are of Royal Berlin ware (Fig. 47). The smaller sizes are glazed on both sides, and the larger are glazed on the inner side, and partly on the outer. The common German porcelain is usually glazed only on the inner side. Platinum dishes (Fig. 48) are used where it is necessary to raise the heat, after the liquid has been driven off. Casseroles (Fig. 49) are porcelain vessels glazed on both sides, having porcelain handles. They may be either of Royal Berlin Ware or ordinary china. The latter are the cheapest, and are quite efficient for many operations. Casseroles are very useful vessels, and having handles are more convenient than evaporating dishes. Evaporation is conducted over the flame of a Bunsen burner (Fig. 45), or by the heat of a water-bath, sand-bath, or air-bath. When the direct flame is employed it is well to rest the vessel on a piece of wire gauze or thin sheet-iron to lessen the liability of breaking. Figure 50 represents a water-bath. It is a copper vessel partly filled with water, and heated by a burner. The top consists of several removable concentric copper rings, to provide different size openings to rest the dishes thereon. The water-bath is used when a gentle heat is, required, i. e., the boiling-point of water (100° Centigrade). Figure 51 shows a sand-bath. It consists of an iron dish filled with sand, and heated with a burner. It is used to obtain a 28 CHEMICAL ANALYSIS FOR GLASSMAKERS. higher degree of heat than that furnished by the water-bath. The sand-bath is also quicker in its operation, and with care in regu- lating the burner flame, loss by spattering may be avoided. Figure 52 represents a simple form of air-bath. It is con- structed of a cylinder a of iron or other material, open at both ends and resting on a piece of wire gauze h. The upper end is covered by a piece of asbestos board c which has an opening in the GENERAL PROCEDURE OF ANALYSIS. 29 center to admit the dish d. The air bath is used to obtain a quick, safe heat, and takes the place of the other baths in many- operations. For operations which evolve noxious fumes, the Fume Closet (Fig. 52 A) will be found desirable. It consists of a wooden box set against the wall, and connected by means of the opening e with the chimney flue of the room. It contains an iron plate a sup- ported on four iron legs, the water-bath 6, the sand-bath c, and the air-bath d. These are all heated by means of the burners /, /, /, /. The closet should be furnished with window sashes, capable of being easily raised or lowered. PAET IV. VOLUMETRIC ANALYSIS. Volumetric analysis is quantitative analysis performed by means of accurately measured volumes of solutions of definite strengths. It possesses the advantages of great rapidity of operation and the use of simple apparatus. For successful operation the following are required: 1. A solution whose exact strength is known, called the Standard Solution. 2. A solution to enable us to determine when a sufficient volume of the Standard Solution has been used. This is called the In- dicator. 3. Apparatus accurately graduated, for measuring the proper volume of the standard solution. The Standard Solution is prepared so that a given volume con- tains a known weight of the reagent used. The standard solutions mentioned in this book are: Sodium Carbonate, Hydrochloric Acid, Potassium Permanganate, Silver Nitrate, Sodium Chloride, Zinc, Potassium Ferrocyanide. The indicators employed with the above-mentioned Standard Solutions, will be described with these solutions. The Graduated Apparatus are: Flasks, Burettes and Pipettes. VOLUMETRIC OR GRADUATED FLASKS. These are shaped as shown in Figure 53, and may be furnished with a glass stopper or closed with a cork. The former are prefer- able when the contents have to be mixed by shaking the flask. These flasks are made to contain the designated volumes when filled to the mark on the neck at a temperature of 15° Centigrade. A convenient set of flasks consists of the following: 50 Cc. , 100 Cc, 200 Cc, 250 Cc, 500 Cc, 1000 Cc, 2000 Cc (30) VOLUMETRIC ANALYSIS. 31 BURETTES. Figures 54 and 55 represent two forms of Burettes. Figure 54 is a Mohr or pinch-cock burette. It has a glass tip a connected with the body of the burette by means of a flexible piece of rubber tubing h. The tubing is closed with a pinch-cock c. By pressing together the ends of the pinch-cock the rubber tubing opens, and allows the liquid to flow from a. This form of burette may be used for all solutions except Potassium Permanganate, as this chemical acts on or corrodes rubber. Figure 55 is a burette which has a glass stop-cock instead of a pinch-cock. This kind may be used for all solutions. It has the disadvantage that the stop-cock is liable to become fast unless well lubricated with vaseline. Liquids w^hich are alkaline, such as Sodium Hydroxide, should never be left overnight in the burette, as they act on the glass and cause the stop-cock to stick. The burette should be made of a glass tube of even caliber, and accurately graduated. The divisions are either engraved or etched 32 CHEMICAL ANALYSIS FOR GLASSMAKERS. on the tube. A very convenient burette is one which deUvers 50 Cc. and is divided into cubic centimeters and tenths of cubic centimeters. To use the burette, fill it with the standard solution until the level of the liquid is above the zero mark. Then open the stop- cock or pinch-cock and allow the liquid to flow out quickly, clos- ing the cock before the level reaches the zero mark. Then open the cock carefully, and allow the liquid to escape drop by drop until the zero mark is reached. The object of first allowing the liquid to flow quickly is to drive out any air that may be in the narrow part of the burette and cock. It will be noticed (Fig. 56) that the surface of the liquid as- sumes the form of a curve, called the meniscus, the lower part of T r,j.5tx Fi^.57. T^i^.^S. Ti<}5S. which is darker than the upper. This dark part must just touch the zero mark, or in other words, the meniscus must be tangent to the mark. This applies also to any mark on the burette. In using the burette the liquid may at first be delivered one cubic centimeter at a time, the flow being gradually diminished at each addition of the liquid. When the end of the test is ap- proached, it is delivered drop by diop. The test should terminate with a single drop. While adding the standard solution, the liquid in the receiving vessel under the burette must be stirred or shaken gently. The operation of using a burette is called titration, from the French word titre, meaning to test or vouch. In order to insure accurate reading of the burette a float is some- times used. This is of glass, and shaped as shown in Figure 57. It has a mark which assists the reading. Figure 58 showu a VOLUMETRIC ANALYSIS. 33 variety furnished with teeth to keep the float from coming into too close contact with the inside of the burette, and to prevent stick- ing. Figure 59 shows the appearance of the float in use. To employ the float fill the burette with the liquid and insert the float. The mark should be above the zero mark of the burette. Allow enough liquid to escape to bring the float mark on the zero mark. When through titrating observe the mark on the burette with which the float mark coincides. In selecting a float be care- ful to have it fit the burette not tight enough to stick, nor loose enough to wobble, but so it freely moves up and down without any side play. When it is necessary to add a given volume of a standard solu- tion, pipettes are employed. Figure 60 represents a graduated pipette. It is made of glass tubing, and has a mark on the upper, narrow part. When filled to this mark, and the liquid allowed to run out, the pipette delivers the proper volume. To use a pipette insert the lower end in the standard solution, and apply the mouth to the upper end. Gently draw up the liquid until it is above the mark, then quickly close the upper end with the forefinger. Carefully move the finger and permit the liquid to escape until the meniscus reaches the mark. Place the lower end against the inside surface of the receiving vessel and remove the finger. When the flow of liquid stops, the proper V PIPETTES. 3 34 CHEMICAL ANALYSIS FOR GLASSMAKERS. volume has been delivered. When the pipette is properly con- structed, it will not be necessary to blow or shake out the last drops. A set of pipettes should consist of the following: 1 Cc. , 2 Cc, 5 Cc, 10 Cc, 15 Cc, 20 Cc, 25 Cc, 50 Cc, 100 Cc Figure 61 shows the manner in which a burette is supported while being used. The iron stand a has the clamp c, which rigidly supports the burette b. This form of clamp is very useful for supporting apparatus of different kinds. The checknut d holds the jaws e at any desired angle. STANDARD SOLUTIONS. Standard Sodium Carbonate. Heat a platinum crucible over a burner and remove to a desic- cator to cool. When cool place it on the pan c of the balance, and on the pan d enough weights to counterpoise. Then place on d more weights, amounting to about 55 grams. Into the crucible put sufficient c. p. dry Sodium Carbonate to bring the balance again into equilibrium. Place the crucible over a burner and heat for about 15 minutes, adjusting the heat so the bottom of the crucible is a dull red. Remove the crucible to a desiccator, and when cool, place it again on the balance pan c. From d take away enough weights to balance the crucible and contents. Now remove from the crucible sufficient Sodium Carbonate so that 53 grams re- main in the crucible. Dissolve the Sodium Carbonate in distilled Avater in a beaker, and pour the solution into a graduated liter flask (Fig. 53). Wash out the beaker into the flask. Fill the flask to the mark with distilled water, and mix thoroughly by pouring into a 1500 Cc. dry beaker, pouring the solution several times back and forth from the beaker to the flask. Thoroughly wash a glass bottle of about 1 liter capacity, washing it finally with distilled water, and draining as completely as possible. Rinse it out with a little of the Sodium Carbonate solution and drain again. Pour the rest of the solution into it and close with a rubber stopper. Label the bottle thus: Standard Sodium Carbonate Na2C03 53 grams per Liter 1 Cc = .053 Cms. NaaCOg 1 Cc = 1 Cc. standard HCl. f VOLUMETRIC ANALYSIS. 35 As this solution is liable to suffer a change of strength on stand- ing, it should be tested occasionally with the Standard Hydro- chloric Acid as described below. Methyl Orange Indicator. Dissolve about .05 grams of c. p. Methyl Orange in 50 Cc. of distilled water, and keep it in a dropping bottle (Fig. 62). If pure it will dissolve to a bright orange-colored solution. One drop will be sufficient for about 100 Cc. of the solution to be tested. When added to alkaline liquids it imparts a faint yellow color, and to acid solutions a pink tint. Standard Hydrochloric Acid. Select some c. p. Hydrochloric Acid having a specific gravity of 1.20. With the hydrometer (see Appendix) verify this specific gravity. Measure out with a graduated cylinder (Fig. 66) about 76 Cc. and pour it into a liter graduated flask (Fig. 53), and fill the flask to the mark with distilled water. Mix thorotighlj'^, as in the case of the Standard Sodium Carbonate. Wash out a burette Avith this acid, and fill the burette with more of it. Bring the level to the zero mark on the burette (Fig. 56). Now fill a 20 Cc. pipette (Fig. 60) to the mark with Standard Sodium Carbonate, and allow it to run into a 100 Cc. Erlenmeyer flask (Fig. 63). Add a drop of Methyl Orange Indicator, and place the flask under the burette. Allow the acid to drop into the flask, observing the 36 CHEMICAL ANALYSIS FOR GLASSMAKERS. precautions given on page 32, and at. the same time shaking the flask with a rotary motion. When a single drop of the acid pro- duces a pink color take the burette reading. If it is found that less than 20 Cc. of the acid is used, then the acid must be diluted so that its strength is the same as that of the sodium carbonate. Suppose we find that 18 Cc. of the acid neutralizes the 20 Cc. of the carbonate, then 900 Cc. of the acid is equal in strength to 3000 Cc. of the carbonate, and we must add 100 Cc. of distilled water to the 900 Cc. of acid in order to equalize the two solutions. The most convenient way to do this is to pour the remaining acid into a mixing jar (Fig. 64), observe the volume, and with a pipette add the proper quantity of distilled water, then insert the stopper and shake thoroughly. The standard acid is to be kept in a clean glass-stoppered bottle which has been rinsed out with a little of the acid, and labeled thus: Standard Hydrochloric Acid HCl 1 Cc. = 37 Gms. HCl 1 Cc. = .053 Gms. Na^COg 1 Cc. = .031 Gms. Na20. The Standard Hydrochloric Acid will retain its strength for an indefinite period, and may be used to correct the Standard Sodium Carbonate. The uses of the Standard Acid will be given under Methods of Analysis. Standard Potassium Permanganate. Dissolve about 6 grams of c. p. Potassium Permanganate (KMn04) in distilled water in a beaker. Take care to get all into solution. As the liquid will be very dark in color, it is well to pour it off into a liter flask, and add more water to the beaker, and apply a gentle heat. When dissolved pour the rest of the liquid into the flask and fill with distilled water to the mark. Now w^eigh out 0. 2 grams of iron piano wire, place it in a 250 Cc. beaker, add 10 Cc. of dilutee, p. Sulphuric Acid (1 part acid to 3 of distilled water) which has been boiled to expel the air. Then add 100 Cc. of hot water, place the beaker under a burette which has been filled with the Permanganate solution, and using the pre- VOLUMETRIC ANALYSIS. 37 cautions given on page 32, add enough Permanganate to produce a faint pink color. While adding, stir the contents of the beaker with a glass rod. Read the burette. Suppose 13.9 Cc. have been used to oxidize the 0.2 grams of iron wire. This weight of this particular kind of wire contains 0.1994 grams of metallic iron, we have 13.9 Cc. KMn04 equals 0.1994 grams Iron (Fe), hence 1 Cc, KMn04 equals 0.0143 grams Fe. Our solution is too strong, and to reduce it we add water, calcu- lating by means of the following proportion: .0143 : 1000 Cc. ::. 01 :x x = 1430. 1430 less 1000 equals 430. Therefore to every 1000 Cc. of Per- manganate solution we must add 430 Cc. of distilled water, in order to make our standard solution of such a strength that 1 Cc. equals .01 grams of iron. This solution also equals .0143 grams of Sesquioxide of Iron (FcgOg), and .005 grams of Lime (CaO). Keep in a glass-stoppered bottle labeled as follows: Steong Standard Potassium Permanganate KMnO^ 1 Cc. = .01 Gm. Fe 1 Cc. = .0143 Gms. Fe^O^ 1 Cc. = .005 Gms. CaO. When testing for small quantities of Iron a weaker solution of Permanganate is used. It is prepared by taking 100 Cc. of the above, pouring it into a liter flask, and filling with distilled water to the mark. This solution is of the strength of the other. Label the bottle as follows: Weak Standard Permanganate 1 Cc. = .001 Gm. Fe 1 Cc. = .0014 Gm. FegOg. Standard Silver Nitrate. Dissolve about 17 grams of c. p. Silver Nitrate (AgNOg) in dis- tilled water in a beaker. Pour into a liter flask and fill with dis- tilled water to the mark. To correct this solution we require one of Sodium Chloride the value of which is known. To make up this latter solution proceed as follows: Place about 2 grams of c. p. 38 CHEMICAL ANALYSIS FOR GLASSMAKERS. Sodium Chloride CNaCl) in a crucible and heat sufficiently to cause the salt to fuse. Carefully weigh out 1 gram of the fused salt, dissolve it in distilled water, pour into a liter flask and fill to the mark. Keep in a glass-stoppered bottle labeled thus: Standard Sodium Chloride NaCl 1 gram per liter 1 Cc. =0.000606 Gm. CI. Dissolve about 10 grams c. p. Potassium Chromate (K2Cr04) in 100 Cc. of distilled water, place it in a bottle and label it Po- tassium Chromate Indicator. With a pipette carefully measure 100 Cc. of the Silver Nitrate solution and allow it to run into a porcelain dish (Fig. 47). Add a drop of the Potassium Chromate Indicator, and from a burette add sufficient Silver Nitrate solution to produce a faint reddish color. While adding, stir constantly with a glass rod, and observe the precautions given on page 32. Carefully note the red color produced, and in subsequent opera- tions stop adding the Silver Nitrate when the same tint is noticed as when adjusting the Standard Silver Nitrate. Knowing the strength of 100 Cc. of the Standard Sodium Chlo- ride, we can calculate the value of the Standard Silver Nitrate Solution. Suppose we found that 17 Cc. of the Silver Nitrate solution produced the red color in the 100 Cc. of Sodium Chloride solution, we have, 17 Cc. Silver Nitrate equals 100 Cc. Sodium Chloride or 17 Cc. = .0606 grams Chlorine (CI), therefore 1 Cc. = .00356 grams Chlorine (CI). Label the bottle containing the Silver Nitrate solution as follows : Standard Silver Nitrate AgNOa 17 grams per liter 1 Cc. = .00356 Gm. CI 1 Cc. = .0059 Gm. NaCl. Standard Zinc Solution. Weigh 10 grams of c. p. metallic zinc in stick form, and place it in a liter flask. Add about 100 Cc. dilute c. p. Hydrochloric VOLUMETRIC ANALYSIS. 39 Acid (1 part acid, 3 parts water). When the Zinc has dissolved fill the flask with distilled water to the mark and mix well. Pour this solution into a glass-stoppered bottle, and label thus: Standard Zinc 10 grams Zn per liter 1 Cc. = .01 Gm. Zn 1 Cc. = .01246 Gm. ZnO. Standard Potassium Ferrocyanide Solution. Weigh out 43 grams of c. p. Potassium Ferrocyanide (K4re- (CN)6). Place it in a liter flask, and dissolve in distilled water. Fill to the mark and mix well. Pour into a glass-stoppered bottle, and label as follows: Standard Potassium Ferrocyanide K,Fe(CN)e 43 grams per liter. This solution must be corrected by means of the Standard Zinc as follows: Carefully measure 10 Cc. of the Standard Zinc Solution with a pipette, and allow it to run into a 50 Cc. beaker. Cau- tiously add the Zinc Solution from a burette. A precipitate will form which will at first be coarse, but which will gradually get finer as more Zinc Solution is added. As the precipitate gets fine take out a drop of the solution with a glass rod, and place it on a china plate in contact with a drop of strong Uranium Acetate solution (5 Gra. to 100 Cc. water). When a brown color appears on the plate the test is finished. Observe the volume of the Ferro- cyanide Solution used, and calculate its value in terms of Zinc. As the Ferrocyanide changes in strength, it must always be tested before use as described above, and the value calculated. PART V. EEAGENTS. The balance used in weighing out the various reagents is of the Robervahl type (Fig. 65). When new it is sensitive to about a ^ gram and will turn with a load of 1 kilo. The weights most convenient to use are Metric block weights of the following de- TicU. nominations: 100 Gms., 50Gms., 20 Gms., two 10 Gm. weights, 5 Gms. , two 2 Gms. and one 1 Gm. They are similar in shape to those shown in Figure 8. Figure 66 represents a graduate measure of cylindrical shape. It is well to have four of these of the following capacities: 1000 Cc, 500 Cc, 250 Cc, 100 Cc. Didilled Water. H^O. When the word Water is employed in this book, Distilled Water is meant. Distilled water is made by evaporating any water and condensing the steam. Figure 67 represents the usual type of still employed, a is a tin-lined copper boiler, fitted with a head h of tin-lined copper. This head with the beak c is detachable from a for convenience in cleaning and filling. The beak c is connected by a union joint d with the worm e. The worm c is of block tin (40) REAGENTS. 41 and passes through the zinc condenser /. Hydrant water is al- lowed to pass into / through a rubber tube to the bottom. The water cools the worm e and escapes at g. Water to be distilled is Figure 68 represents the Domestic Water Still. This has the 42 CHEMICAL ANALYSIS FOR GLASSMAKERS. advantage of being continuous in its operation, and requires little attention. Figure 69 shows a contrivance for obtaining distilled water from the waste steam of a factory boiler. The steam enters the iron cylinder a through the cock e, it passes through closely packed gravel with w^hich a is filled, and enters the block-tin pipe h which is continued in the worm c which is also of block tin. Cold water to cool the worm c is admitted to the iron cylinder d by means of the cock g. It fills d and escapes at h. The condensed steam is collected at /. The cylinder a is emptied of any water of con- densation by means of the cock k. Distilled water should have no odor, and exhibit no reaction when tested with litmus paper (see page 51). It should give no precipitate when Silver Nitrate or Barium Chloride is added, and no residue when evaporated to dryness. ACIDS. Sulphuric Acid. H^SO^. There are two kinds employed, the commercial, and the chem- ically pure. The former is used for the evolution of gases, such as Carbon Dioxide, Sulphuretted Hydrogen, etc. The chemically pure acid should be colorless, and should give no odor when shaken. When a colorless solution of ferrous sulphate is poured into it, the liquids in contact should give no brown tint. When poured on pure zinc, and the resultant gas passed through a glass tube, and burned, and the flame allowed to touch a clean porcelain dish, no metallic film must be deposited. To dilute add cautiously one part of acid to five parts of water. Nitric Acid. HNO^. Pure Nitric Acid is colorless, and leaves no residue when evap- orated in a platinum dish. When diluted with water, and a solu- tion of Silver Nitrate or Barium Chloride is added, no turbidity should appear. On standing for a time Nitric Acid becomes yel- low in color, this may be removed by blowing air through the acid. Dilute Nitric Acid is made by adding an equal volume of water. REAGENTS. 43 Hydrochloric Acid. HCl. There are two kinds used, the commercial and the chemically pure. The former is used for the evolution of gases. The latter should be colorless, and when evaporated leave no residue. It should remain colorless during evaporation. When mixed with water and a solution of Barium Chloride added, no precipitate or turbidity should appear. When neutralized with Anmionia, and Ammonium Sulphide added, no precipitate should form. To dilute add one part of acid to two parts of water. Nitro Hydrochloric Acid. Aqv,a Regia. This is formed by mixing 1 part of Nitric Acid with 3 parts of Hydrochloric Acid. This reagent is not to be used diluted. Hydrofluoric Acid. HF. This acid when pure must leave no residue when evaporated in a platinum dish. As it attacks glass it is put up in Cerasine bottles. Acetic A aid. 0^ H^ 0 ^ ■ This acid should have a specific gravity of 1,04. It should leave no residue on evaporation, and give no precipitate when tested with Hydrogen Disulphide, Silver Nitrate, or Barium Chloride. When neutralized with Ammonia and Ammonium Sulphide added, it should not become cloudy. Bromine. Br. Bromine is a dark brown liquid of specific gravity 2.97. It is very corrosive, and the fumes should not be breathed or allowed to come in contact with the eyes. It is to be kept in a glass- stoppered bottle furnished with a ground-glass cap. A solution known as Bromine Water is used, made by placing about 25 Cc. in an 8-oz. bottle, and filling the bottle with water and shaking. As the solution is used up, more water is added. GASES. 'Carbon Dioxide. Carbonic Acid. CO 2' This gas is formed when a carbonate is acted on by an acid. Calcium Carbonate (Chalk, Marble, Limestone) and Sulphuric or 44 CHEMICAL ANALYSIS FOR GLASSMAKERS. Hydrochloric Acid are commonly used. Figure 70 shows a simple apparatus for producing this gas. The flask a is fitted with a two- hole rubber stopper b through which passes the funnel c and the tube d. The tube d is bent to enter the bottle e which contains water to wash the gas, the gas escaping through the tube /. Figure 71 represents a Kipp Gas Generator which is used when quantities of gas are required. The upper part a is extended into a tube b which reaches almost to the bottom of c. The part b should be of such a diameter as to barely pass through the bottom of d. The substance acted upon by the acid is placed in d, and the acid poured through the funnel / into c until it rises in d. The gas escapes at g. The spent acid may be drawn off at h. Hydrogen Sulphide. H2S. This gas is formed by the action of Sulphuric or Hydrochloric Acid on Ferrous Sulphide. Either of the apparatus described REAGENTS. 45 above may be used. For adding small volumes of this gas to solutions, the apparatus described in Figure 72, designed by Dr. A. H. Elliott, will be found very convenient. The Ferrous Sul- phide is placed in the 8-drachm homeopathic vial a fitted with a one-hole rubber stopper b through which passes the tube c which is enlarged to admit a plug of cotton in d. A bent tube e is fitted into a cork / which is inserted in d and delivers the gas. Hydrogen Sulphide is also used in solution. This is made by Tift. T,^.73, passing the gas through distilled water, until strongly saturated which maj^ be perceived by the odor given when the solution is shaken. Hydrogen. H. This gas is formed when Zinc is acted on by Sulphuric or Hydrochloric Acid. The apparatus described under Carbonic Acid may be employed. Oxygen. 0. Oxygen may be made by heating a mixture of 100 parts Potas- sium Chlorate and 5 parts Man- ganese Dioxide, in a copper retort (Fig. 73). The gas thus pro- duced may be collected in rubber gas-bags (Fig. 74). For labora- tory purposes it is best to pur- chase the gas compressed in cylinders, which may be procured in various sizes. 46 CHEMICAL ANALYSIS FOR GLASSMAKERS. ALKALIES AND ALKALINE SALTS. Sodium Hydroxide. NaOH. This reagent may be purchased in a sufficiently pure state. It comes in the form of sticks and must be kept from the air. It is best preserved in a wide-mouth, glass-stoppered bottle. Potassium Hydroxide. KOH. This is in the same form as Sodium Hydroxide, and must be preserved with the same precautions. Ammonium Hydroxide. NH^OH. This is sold as Stronger Water of Ammonia, and has a density of .90. The solution used in ordinary laboratory operations is formed by adding one part of distilled water to one of ammonia. It should be colorless and leave no residue when evaporated to dryness in a platinum dish. An equal volume of lime water, added to the diluted Ammonia should cause but slight turbidity. Ammonium Sulphide. (NH^^)^'^- This is formed by passing Hydrogen Disulphide through dilute Ammonia until the latter is saturated. It should be kept in glass- stoppered, amber-colored bottles. Sodium Carbonate. Na^CO^. The dry salt is used. It should be perfectly white, and should dissolve in water without leaving any residue. "When the solution is made acid with Nitric Acid and Barium Chloride added, no precipitate or turbidity should form. When tested in the same manner with Silver Nitrate, no turbidity should appear. When evaporated to dryness with Hydrochloric Acid, re-dissolved in Hydrochloric Acid, and again evaporated and re-dissolved, no insoluble residue should remain. Potassium Carbonate. K^CO^. This salt should also be procured in the dry state, and tested for impurities in the same manner as Sodium Carbonate. Flux for Silicates. Mix in a clean dry porcelain dish 53 parts by weight of Sodium REAGENTS. 47 Carbonate, and 70 parts by weight of Potassium Carbonate, and keep in a glass-stoppered, wide-mouth bottle. This flux is used to effect fusion in the analysis of glass and other silicates. Ammonium Carbonate. (NH^) ^CO^. This salt is in the form of transparent crystals. When exposed to the air a white crust forms, which should be scraped off before dissolving. The pure salt should entirely volatilize when heated. After adding Nitric Acid in excess to a solution of Ammonium Carbonate no precipitate should form when tested with Hydrogen Sulphide, Silver Nitrate or Barium Chloride. When used as a reagent one part by weight is dissolved in a mixture of water (four parts) and ammonia (one part). Amm.onium Chloride. NH^Cl. This is referred to under J. Lawrence Smith's method for the determination of Alkalies in Silicates (see page 85). Ammoniim, Oxalate. {NH^) 2^2^4-^^2^' It is used in the form of white crystals. The solution should remain clear when tested with Hydrogen Sulphide, and the salt should entirely volatilize when heated on platinum. For use dis- solve one part by weight in twenty-four parts of water. Sodium Ammonium Phosphate. NaNH^PO^.JiH„0. This is also known as Microcosmic Salt. It is to be dissolved in six parts cold water, but should not be kept in solution, as it acts on glass. It should be made up as required. Hydrogen Di-Sodium Phosphate. Na ^ HPO^ . 0. It is also called Sodium Phosphate. It should be dissolved as required, as it attacks glass. The proper solution is one part in ten of water. Potassium Nitrate. KNO^. This is in the form of white crystals, and may be procured in a sufficient state of purity. Sodium Nitrate. NaNO^. This salt is similar in properties and uses to the above. 48 CHEMICAL ANALYSIS FOR GLASSMAKERS. Potassium Bichromate. Cr^O^. An orange-colored crystalline salt, referred to in this book under Volumetric Analysis. Potassium Bisulphate. KHSO^. A white crystalline salt which, when dissolved in a large excess of water, decomposes into Potassium Sulphate and Sulphuric Acid. When heated it gives off first its combined water, and when the heat is raised to redness Sulphuric Acid escapes. Sodium Bisulphate. NaHSO^. Similar in appearance and properties to the above. Potassium Ferrocyanide. Fe ( CN) g . A yellow crystalline salt which is used in testing for Iron. It gives a blue coloration of ferrocyanide of iron (Prussian Blue) when ferric iron is present. For use as a I'eagent dissolve one part of the salt in tv.'elve of water. Potassium Ferricyanide. K^Fe{CN) A blood-red crystalline salt used for testing the presence of fer- rous iron, with which it produces a blue color. Ferric salts pro- duce no color. Should be made up as wanted and not kept in solution. Potassium Permavganate. KMnO^. This salt is in the form of purple-colored, needle-shaped crystals. It is referred to in this book under Volumetric Analysis. It is readily obtained in a pure state. Potassium Thiocyanate. KCNS. A colorless crystalline salt. When used as a reagent one part is dissolved in ten parts of water. When Hydrochloric Acid is added to this solution it should remain colorless. It is used as a test for very small quanties of iron in the ferric state. When added to a ferric solution a deep-red color is produced. Sodium Chloride, Salt. NaCl. This is used to prepare the Standard Salt Solution, page 38. The best grades of table salt being very pure, are suitable for use as this reagent, provided the solution is not precipitated or ren- REAGENTS. 49 dered turbid by Ammonium Oxaliite, Sodium Pbosphate, or Barium Chloride. Soda Lime. This is referred to under Methods of Analysis, Lime. It is an absorbent for Carbon Dioxide (CO2) and Water (HgO). It is pur- chased in the form of brownish lutnps. ALKALINE EARTH SALTS. Barhim Chloride. BaCl2.2H^0. A white crystalline salt used in the determination of Sulphur. It is to be dissolved in the i)Toportion of one part to ten of water. Calcium Chloride. CUCI2. It is used as a reagent and as an absorbent for hygroscopic- moisture. In the latter case it is in the form of porous lumps. See Desiccator, General Procedure of Analysis. Calcium Carbonate. CaCO^. This reagent is referred to in this book under Determination of Alkalies in Silicates, in the method of J. Lawence Smith. When used for this purpose it should be in the form of a white powder, which should not give any blue color when shaken up in water and a drop of litmus added. This shows the presence of alkalies, and is peculiar to Calcium Carbonate, which has been made by, precipitation with Sodium Carbonate and not properly washed. It may be purified by placing on a filter-paper in a funnel, and thor- oughly washing with hot water. Magnesia Mixture. This reagent is referred to on page 75, Determination of Arsenic. It is made by dissolving 55 grams of crystalh'zed Magnesium Chlo- ride in water and filtering, then dissolving 14 grams of Ammonium Chloride in water, adding a little Bromine water and an excess of Ammonia, and filtering. This second solution is added to the first, more Ammonia is added to give a decided odor, and the solution diluted to about a liter, transferred to a bottle and shaken well. When required a sufficient quantity is passed through a filter and used. 4 50 CHEMICAL ANALYSIS FOR GLASSMAKERS. METALS AND METALLIC SALTS. Iron Wire. Fe. This is used to standardize the Potassium Permanganate Volu- metric Solution (page 36). It may be obtained from dealers in chemicals, and before being weighed should first be cleaned with emery-paper and then Aviped with filter-paper. Ferrotis Sulphate. FeSO^.JH^O. This is used in qualitative analysis in testing for nitrates. It is in the form of pale green crystals, which, when dissolved in water, must leave no brownish-yellow Ferric Sulphate undissolved in the solution. When Hydrochloric Acid is added to the solution, and Hydrogen Sulphide gas passed into it, no precipitate or black tint must be produced. Cupric Sulphate, Anhydrous. CuSO^. Heat crystals of C. P. Copper Sulphate in a porcelain crucible until the combined water is driven off, that is, until they turn white. This salt is used in the U tube of the CO 2 apparatus, de- scribed on page 64, for the absorption of any chlorine that may be liberated. Platinic Chloride. PtCl^. It is used to separate Potassium from Sodium in the analysis of glass, clay, etc. It can be purchased, or may be made from scraps of metallic Platinum which accumulate in the laboratory. The following method of Fresenius may be employed: Place about five parts by weight of metallic zinc in a clay crucible and cover with some common salt to prevent oxidization. Heat until the zinc is melted, and add little by little one part of the platinum scraps. When the last addition is melted remove the crucible, and when cold dissolve the alloy formed in dilute Hydrochloric Acid. When effervescence has ceased add more acid and boil for a short time. Pour off or filter the platinum which is left, and thoroughly wash with water. Boil it in nitric acid and wash again. Dissolve in Aqua Regia and evaporate on the water-bath, adding a little Hydrochloric Acid from time to time. When in a syrupy condition dissolve in ten parts of water. Platinic Chloride may also be made from the washings .which REAGENTS. 51 come from the separation of Potassium and Sodium (page 85) by the following method: The solution containing the platinum salts is boiled in a beaker, and sufficient Ferrous Sulphate added to give it a greenish tint. Then add about one gram of granulated sugar and boil for a short time. Filter o£E tbe precipitated Plati- num Black and wash with hot water. Remove to a casserole and gently heat with Hydrochloric Acid. Pour off the acid, keeping the platinum black in the casserole, and wash three times with hot water, pouring off the water each time. Add a little Nitric Acid and heat again. Then add more Hydrochloric Acid and evaporate on the water-bath until the mass is of the consistency of syrup. Dissolve in ten parts of water for use. Silver Nitrate. AgNO^. This reagent is in the form of white crystals which must be kept in a stoppered bottle of dark color, to prevent the action of light. For use dissolve 1 part of the crystals in 20 parts of water. To test the solution for purity add Hydrochloric Acid until no more precipitate forms. Filter, and pass Hydrogen Sulphide gas into the filtrate ; no precipitate or turbidity should appear. Zinc. Zn. Metallic Zinc for analysis may be purchased chemically pure in the form of sticks. It is used to reduce iron to a ferrous state, and in the preparation of hydrogen gas. LITMUS PAPER. This reagent is an indicator used to determine whether a solution is acid or alkaline. It may be purchased in sheets and cut into strips. It should be kept in a glass-stoppered bottle, so as not to be affected by the fumes of the laboratory. The paper is colored either red or blue. Acid solutions will change the color of the blue paper to red, and alkalies will restore the color or turn the red paper blue. TURMERIC PAPER. This is of a brownish-yellow color, and is used to test for the presence of Boron compounds (Borax, etc.), which cause it to as- sume a reddish tint. Reagents in solution should be kept in glass-stoppered bottles, 52 CHEMICAL ANALYSIS FOR GLASSMAKERS. properly labeled, A good form of reagent bottle is shown in fegure 75. It has the advantage of an indestructible label, the name and symbol of the reagent being blown in the glass. It is sold at a reasonable price. Paper labels should be avoided if possible on reagent bottles, as they are being continually destroyed by the liquid running down the bottle. When they are unavoid- able they should be covered with a thin coat of paraffin. A con; venient size of reagent bottle is 8 ounces, or 250 Cc. Fig. 75. PART VI. METHODS OF ANALYSIS. SODA ASH. Sodium Carbonate, Carbonate of Soda, Na^CO^. Total Alkali or Oxide (NajO), Alkalinity or Test Degree. Weigh out 3.1 grams and brush it into a 50 Cc. beaker. Add about 25 Cc. hot water and boil until the soluble part has been dissolved. Filter through a 9 Cm. paper into a 100 Cc, Erlen- meyer flask (Fig. 63) and wash the filter three times with hoi water. To the liquid in the flask add a drop of Methyl Orange Indicator, and place the flask beneath a burette which contains the standard Hydrochloric Acid, prepared as on page 35. Cautiously add the Standard Acid, 1 Cc. at a time, until about 40 Cc. are in, shaking the flask at the same time with a rotary motion. Then add more Standard Acid, a few drops at a time, and as the test approaches the end, one drop at a time. When a single drop pro- duces a full pink color the test is finished. The number of Cc. and tenths of acid used will be the degree of alkalinity or per cent, of NagO in the ash. This number multiplied by 1.71 will give the per cent, of carbonate or NagOOg. Example: Weight of Soda Ash taken for analysis, 3. 1 grams. Cc. Standard Acid used, 46.0 Cc. Per cent, of NagO or test degree, 46.0 per cent. Per cent, of Na 2 CO 3, 78.66 " In case the results are wanted quickly the solution in water and filtering may be dispensed with as follows: Weigh 3.1 grams of the ash and brush it into an Erlenmeyer flask. Add about 10 Cc. of cold water and shake gently. Add a drop of Methyl Orange Indicator, and remove to the burette and allow the acid to drop in (53) 54 CHEMICAL ANALYSIS FOR GLASSMAKERS. as described above. The results will be slightly high on account of the insoluble lime compounds using up some of the acid. DETERMINATION OF SALT, OR SODIUM CHLORIDE. Salt is present in Soda Ash as an impurity or adulterant. It is sometimes added to 58 per cent, ash to reduce the strength to 48 per cent. Weigh out 1 gram of Soda Ash, brush it into a 25 Cc. beaker, and add 10 Cc. of hot water. Cover the beaker with a watch-glass, and from a smaller beaker add carefully 5 Cc. of dilute Nitric Acid. While adding the acid keep the watch-glass on the beaker to avoid loss by effervescence. Boil gently until effervescence ceases. Re- move from the burner, and with the wash-bottle rinse off the watch-glass, allowing the rinsings to fall into the beaker. Filter through a 7 Cm. filter-paper into a 50 Cc. beaker, and wash the first beaker into the funnel, using a jet of hot water from the wash- bottle. Wash the filter three times with .hot Avater. Place the beaker over a burner and heat gently to boiling. While boiling add about 10 Co. of Silver Nitrate Solution. While adding this reagent keep stirring the boiling solution with a glass rod. Con- tinue stirring and boiling until the precipitated Silver Chloride settles, leaving the liquid above it clear. Remove the beaker from the burner and set it aside to settle thoroughly. Filter through a 11 Cm. ashless filter-paper and wash with hot water, observing the precautions given on pages 16 to 18 regarding the complete removal of the precipitate from the beaker. Wash with hot water until the washings give no residue when the last few drops are evaporated on the cover of a platinum crucible. Place the" funnel containing the filter-paper in an air-bath, and when dry burn the paper as directed on page 23. Ignite in a weighed porcelain crucible and allow to cool. When cool add a drop of strong Nitric Acid, and gently heat by moving the burner to and fro beneath the crucible, taking care not to allow the acid to spatter. When dry ignite strongly until the contents of the crucible are white. Remove to a desiccator, allow to cool, and weigh. The weight of the Silver Chloride multiplied by 40.85 will give the per cent, of Salt or So- dium Chloxide in the Soda Ash. METHODS OF ANALYSIS. 5§ Example: Weight of Soda Ash taken, 1 gram. Weight of crucible, cover and Silver Chloride, 35.9873 > Weight of crucible and cover, 35.6392 Weight of Silver Chloride (AgCl), .3481 .3481 X 40.85 = 14.22 per cent, of Salt, NaCl. Note: The object of adding the Silver Nitrate when the solutiori is boiling is to insure precipitation in a granular form, thus causr ing it to settle quickly. If the chloride comes down in a fine pre^ cipitate it is liable to run through the filter-paper. , RAPID METHOD FOR SODIUM CHLORIDE. Dissolve 1 gram of Soda Ash in 25 Cc. of water in a porcelain dish, cover the dish with a watch-glass, and add sufficient strong Nitric Acid to make a shght excess, that is, to turn litmus-paper red. Boil gently until no more bubbles of Carbonic Acid escape, then add little by little dry c. p. Sodium Carbonate until the Litmus paper is blue when placed in the solution. Remove the watch-glass and wash it with a jet of cold water. Place the dish beneath a burette which contains standard Silver Nitrate. To the contents of the dish add two drops of Potassium Chromate indi- cator, and allow the standard solution to drop in, proceeding; exactly as described on page 38. When the red color is produce^ the test is finished. ; Example: 1 gram Soda Ash. Silver Nitrate used 24.1 Cc. X (.0059 X 100) = 14.219 per cent. Salt, NaCl. Determination of Salt Cake or Sodium Sulphate. Na2S0^. This may be present as an impurity in Ash which has been made by the Le Blanc process, or it may have been purposely added to Ash to be used for Amber glass. Weigh 5 grams of Soda Ash into a 25 Cc. beaker. Add 10 Cc. of hot water and 5 Cc. of strong c. p. Hydrochloric Acid, at the same time keeping the beaker covered with a watch-glass, and add- ing the acid gradually from a smaller beaker. Boil gently for a few minutes. Remove the watch-glass and wash its surface with a jet of hot water, allowing the washings to run into the beaker.- 56 CHEMICAL ANALYSIS FOR GLASSMAKERS. Filter througli a 7 Cm. filter-paper into a 50 Cc. beaker, and wash out the first beaker with a jet of hot water, allowing the washings to run into the funnel. Wash the filter three times Avith hot water. Bring the contents of the 50 Cc. beaker to boiling, and while boil- ing add 10 Cc. of solution of Barium Chloride. Stir witli a glass rod while boiling, and continue stirring and boiling for about one minute. Set the beaker aside to settle. Then filter through an 11 Cm. ashless filter-paper. Wash out the beaker into the funnel, observing the precautions given on pages 1 6 to 1 8. When the beaker is clean wash the filter three times with hot water, or until the last drops running through the funnel give no turbidity when tested on a watch-glass with a drop of Silver Nitrate solution. Place the funnel in an air-bath, and when dry remove the filter- paper and allow the contents to fall on a glazed paper, taking care to detach as much of the precipitate as possible from the filter-paper. Burn the filter-paper as described on page 23, and ignite it in a weighed porcelain crucible. Brush the precipitate from the glazed paper into the crucible and ignite again for about 15 minutes. Allow to cool and add a drop of c. p. strong Sulphuric Acid. Heat tery gently by moving the burner flame to and fro beneath the crucible. When all tbe white fumes cease, ignite strongly until the contents of the crucible are white. Remove to a desiccator and weigh when cool. The weight of the Barium Sulphate found multiplied by 12.24 will give the percentage of Sodium Sulphate present in the Soda Ash. Example: 5 grams Soda Ash taken. Weight of crucible, cover and BaS04, 37.2162 Weight of crucible and covei, 36.9337 Weight of BaSO^, .2825 .2825 X 12.24 =3.46 per cent. Sodium Sulphate. DETERMINATION OF SILICA, ALUMINA, FERRIC OXIDE, AND LIME. Weigh 10 grams of the Ash into a platinum crucible and heat over a blast-lamp until entirely fused. Grasp the crucible witli the tongs and dip it into cold water to about one-half its depth. This sudden cooling causes the fused mass to shrink away from the crucible and renders its removal easy with the aid of a glass METHODS OF ANALYSIS. .57 rod. Allow the cooled mass to drop into a 50 Co. porcelain casse- role. Pour in enough hot water to cover the button and place a watch-glass on the casserole. Half fill the platinum crucible with c. p. dilute Hydrochloric Acid and pour this into a small beaker. Then wash the crucible into this beaker. Carefully add the con- tents of the beaker to the casserole, and wash the beaker into the casserole. Place the covered casserole on an air-bath (Fig. 52) and heat gently. When effervescence has ceased take off the cover and wash it with a jet of hot water into the casserole. Add a drop of strong Nitric Acid and allow the contents of the casserole to evaporate to dryness, redissolve in a little dilute Hydrochloric Acid, evaporate again to dryness. Then add about 25 Cc. of dilute Hydrochloric Acid and filter through a 9 Cm. ashless filter-paper. Wash out the cas<^erole with hot water and wash the filter until the last drops from the funnel give no reaction when tested with Silver Nitrate solution. Remove the filter-paper from the funnel while still wet and place it in a weighed platinum crucible. Gently heat with a blast-lamp, and when the paper is dry raise the heat and continue igniting until the contents of the crucible (Silica, SiOa) are white. Cool the crucible in a desiccator and weigh. Subtract the weight of the crucible, and the difference will be Silica, SiOg, which multiplied by 10 will give the per cent. Treat the filtrate from the Silica exactly as described under Silicate Analysis, page 83, and determine the Alumina, Ferric Oxide and Lime in the same manner as described in that method. DETERMINATION OF MOISTURE. Weigh a platinum or porcelain dish on the balance pan. Then place a 5-gram weight with the other weights, and in the dish suffi- cient Soda Ash to balance. Remove the dish to a drying-oven (Fig. 37) and heat at 100° C. for about a half hour. Remove the dish to a desiccator to cool, and then weigh it with its contents. Place again in the drying-oven for another half hour and weigh again. Continue drying and weighing until two successive weights are obtained which do not differ more than two milligrams. The loss of weight multiplied by 20 represents the percentage of Moist- ure (HjO) present in the Ash. 58 CHEMICAL ANALYSIS FOR GLASSMAKERS. Example: 5 grams Ash. Weight before heating, 37.6700 Weight after first heating, 37.5640 Weight after second heat- ing, 37.5620 Loss of weight, .1080 x 20 ^ 2.16 per cent. Moisture. NOTES OF A COMPLETE SODA ASH ANALYSIS. Determination of Soda, 3.1 grams taken: Standard Acid used, 46 Cc, equals 46 per cent. Soda, or 78.66 per cent. Sodium Carbonate. Determination of Salt, by weight or gravimetrically, 1 gram taken : Weight of crucible, cover, and AgCl, 35.9873 Weight of crucible and cover, 35.6392 Weight of AgCl, .3481 X 40.85 = 14.22 per cent. Salt. Determination of Salt with standard Silver Nitrate or volumet- rically, 1 gram taken: Standard Silver Nitrate used, 24.1 Cc, X (.0059 X 100) = 14.22 per cent. Salt. Determination of Salt Cake, 5 grams taken: Weight of crucible, cover and BaS04, 37.2162 Weight of crucible and cover, 36.9337 Weight of BaS04, -2825 X 12.24 = 3.46 per cent. Salt Cake. Determination of Silica, Alumina, Ferric Oxide and Lime, 10 grams taken: Weight of platinum crucible, cover and Silica (SiOa), 36.9033 Weight of platinum crucible and cover, 36.8605 Weight of Silica (SiOg), .0428 X 10 - 0.43 per cent. Silica. METHODS OF ANALYSIS. 59 Filtrate divided into two parts and treated as under Silicate Analysis. Part I., or 5 grams. Determination of Ferric Oxide, Fe203: Weak standard Permanganate, 5.5 Cc, X .0014 = .0077; .0077 X 20 = 0. 154 per cent. FcaOg. Part II., or 5 grams: Weight of crucible, cover, Alumina and Ferric Oxide, 36.1300 Weight of crucible and cover, 36.0836 Weight of Alumina and Ferric Oxide, .0464 Weight of Ferric Oxide found from Part I., .0077 Weight of Alumina (AI2O3), .0387 X 20 = 0.774 per cent. Alumina. Filtrates from Parts I. and II. combined to determine Lime. Parts I. and II., 10 grams. Strong standard Permanganate, 0.6 Cc, X .005 = .003 X 10 = 0.03 per cent. Lime. Summary of Analysis : Soda 46 per cent. Sodium Carbonate, NagCOg, 78.66 Salt, or Sodium Chloride, NaCl, 14.22 Salt Cake, or Sodium Sulphate, Na2S04, 3.46 Silica, SiOg, .43 Alumina, AI2O3, .77 Ferric Oxide, FcaOg, .15 Lime, CaO, .03 Moisture, H 2 0, ' 2.16 99.88 percent. 60 CHEMICAL ANALYSIS FOR GLASSMAKERS. SALT CAKE. Sodium Sulphate, iVa,2'S'04. Determination of total Sulphate: Weigh 1 gram of the Salt Cake into a 50 Cc. beaker and add about 10 Cc. of hot water and 5 Cc. of c. p. strong Hydrochloric Acid. Heat gently until dissolved, and filter through a 7 cm. filter paper into a 150 Cc. beaker. Wash out the first beaker on to the filter paper, and wash the filter three times with hot water. Heat the filtrate to boiling, and add 15 Cc. of hot Barium Chloride solution, as described under Soda Ash, determination of Salt Cake, page 56. Stir with a glass rod, filter, dry and ignite the precipi- tated Barium Sulphate as described on page 56. The weight of BaS04, multiphed by 61.21, will give the percentage of Sodium Sulphate. Example, 1 gram taken: Weight of crucible, cover and BaS04, 35.9786 Weight of crucible and cover, 34.4950 Weight of BaS04, 1.4886 1.4836 X 61.21 = 90.81 per cent. Sodium Sulphate. Determination of Salt, Sodium Chloride, NaCl: As Salt Cake is made directly from common salt, it is liable to contain more or less of it, according to the care which has been taken in the manufacturing process. Proceed exactly as directed under Soda Ash, pages 54 and 55, using either method. Determination of Silica, Alumina, Ferric Oxide: Weigh 10 grams of the Salt Cake, and brush it into a 200 Cc. beaker. Dissolve in about 25 Cc. of dilute Hydrochloric Acid. Filter through a 7 Cm. ashless filter paper into a 500 Cc. porce- lain casserole, and wash the beaker on to the filter paper, using a jet of hot water. Wash the filter paper three times with hot water, and place it still wet in a platinum crucible. Heat over a blast lamp until the paper is reduced to ashes. Then place in the crucible about 1 gram of c. p. Sodium Carbonate. Renew the heat and bring the contents of the crucible to fusion. Cover the crucible, and when cool, add, cautiously, about 5 Cc. of dilute Hydrochloric Acid. Empty the crucible into the casserole, wash it with a jet of hot water, and wash the cover off also into the casserole. Place the casserole on an air bath and evaporate to METHODS OF ANALYSIS. 61 dryness. Then redissolve in a little dilute Hydrochloric Acid, and proceed exactly as described on pages 81 to 84, omitting the de- termination of Lime. Determination of Moisture, H2O; Proceed exactly as described on page 57, determination of Moisture in Soda Ash. Example of a complete analysis of Salt Cake: Sodium Sulphate, Na2S04, 90.81 Sodium Chloride, NaCl, 6.61 Moisture, HgO, 1.53 Silica, Si02, .50 Alumina, AI2O3, .28 Ferric Oxide, Fe20 3, .12 99.85 per cent. Sodium Nitrate, NaNO^. Determination of Sodium Chloride, NaCl: Common salt is present in commercial nitrate as an impurity. To determine its percentage^ proceed as follows: Weigh 5 grams of the nitrate into a 100 Cc. porcelain dish, and add about 50 Cc. of cold water. Stir with a glass rod until dissolved. Add two drops of Potassium Chromate Indicator, and with a burette, as before described, drop in sufficient Standard Silver Nitrate Solution to produce the proper red color. The number of Cc. of Standard Solution used gives the weight of Sodium Chloride present, and this result, multiplied by 20, gives the percentage. Example, 5 grams taken: Standard Silver Nitrate used, 6.1 Cc. 6.1 X .0059 X 20 = 0.72 per cent. NaCl. Determination of Moisture, HgO: Weigh 10 grams of the Nitrate into a platinum dish, heat for a half hour in the drying oven, as directed on page 57, under Soda Ash. The loss of weight will be moisture. Example, 10 grams taken: Weight of dish and Nitrate before heating, 42.2706 Weight after 1st heating, 42.1480 Weight after 2d heating, 42. 1350 W^eight after 3d heating, 42.1350 Loss of weight, or moisture, 0.1356 grams, or 1.356 percent. HjO. 62 CHEMICAL ANALYSIS FOR GLASSMAKERS. Sodium Bicarbonate, NaHCO^. The constituents to be determined are Combined Water (HjO), Carbon Dioxide (CO2) and Alkali (NagO). They are to be cal- culated to total Bicarbonate. The impurities are Sodium Monocarbonate (Na2C03), Moisture (H2O), Sodium Chloride (NaCl) and Sodium Sulphate (Na2S04). The three last named are determined exactly as described under Soda Ash. The Sodium Monocarbonate (NagCOa) is calculated from the determination of the ingredients. Determination of Water, H2O: A piece of platinum foil a (Fig. 76), about 3 inches by 1 inch is cut along the dotted lines and bent into the form of a boat as shown in h. The boat is placed on the balance pan and weighed. One gram of the bicarbonate is then weighed into it, and the boat is placed in a hard glass tube Avhich is arranged as shown in Figure 77 c, is a bottle half full of strong Sulphuric Acid to dry the air passing into the tube d. This bottle is furnished with two bent glass tubes passing through a rubber stopper ; the left hand tube extending below the surface of the acid, the right hand tube passing through another rubber stopper fitted into d. d is the hard glass tube containing the boat h, and connected with the U tube e by means of another rubber stopper. The U tube e is filled with dry, granular Calcium Chloride, and when ^ not in use the ends are closed by means of short pieces of rubber tubing stoppered by bits of glass rod, as shown in j j. It has a loop of yv , platinum wire k to hang it to the balance hook \ ' — 7 ^ when weighing. The tube e should be about 4 inches long, and before using, the Calcium Ti^ Tfc. Chloride in it must be saturated by Carbonic Acid gas, which is made as described on page 43. The tube e is connected with an aspirator bottle/ of about 2 gallons capacity, having the tablature or outlet g furnished with a bent glass tube and a rubber tube closed by the screw pinch cock h. The burner I is placed under d. The apparatus is supported by means of a burette clamp m, attached to the stand n. Weigh the tube e and connect it with d and /. After placing the boat in the tube ascertain if the joints are all tight by allow- ing the water to drop from g. Light the burner Z, and gently heat METHODS OF ANALYSTS. 63 the tube d. Gradually raise the heat until the tube is red hot, keeping g open all the time. Maintain a red heat for about 20 minutes, and then extinguish the burner flame and allow the water to continue running from g until the tube d is cool. Re- move the U-tube e, close it with the caps j, j, hang it on the bal- ance hook by means of the loop A:, and weigh it. The increase of weight will be the water originally contained in the Bicarbonate. Remove the boat b and weigh it with its contents; the decrease in weight will be the water plus one-half of the Carbon Dioxide of the Bicarbonate. Determination of Carbon Dioxide, (CO2): Prepare an apparatus according to Figure 78. A 120 Cc. Erlen- meyer ' flask a is supported by the clamp b and stand c, and is heated by the burner d. The flask is closed by a rubber stopper e, which has two holes. Through one hole is passed the stem of the separating funnel / reaching nearly to the bottom of a. A bent glass tube g is fitted into the other hole, and connected by a piece of rubber tubing to another glass tube h, which goes through a two-hole rubber stopper into an empty 2-oz. glass bottle j, reach- ing nearly to the bottom. Another bent glass tube k placed in the other hole, connects by means of rubber tubing, with the bent tube / entering the 2-oz. glass bottle m, which is nearly one-half full of concentrated Sulphuric Acid. The glass tube n connects m with a 6-inch U-tube 0 which is filled with pieces of pumice stone saturated with strong Sulphuric Acid. The tube 0 is connected G4 CHEMICAL ANALYSIS FOR GLASSMAKERS. with another U-tube p filled with Anhydrous Copper Sulphate (page 50). The tube j9 is connected by means of a flexible rubber tube g with an absorption tube r described below. The rubber tube 8 connects rwith the 8-inch U tube t filled with dry, granular Calcium Chloride. The 2-gallon aspirator bottle u completes the apparatus. It has a glass stop-cock v to regulate the flow of water. Instead of an aspirator bottle a filter pump (Figs. 35, 36) may be used. The absorption tube r is composed of a six-inch U-tube, filled with Soda Lime (page 49), and a four-inch U-tube filled with pieces of pumice stone, saturated with strong Sulphuric Acid. It is closed by caps, as described in Figure 77, tube e. The pumice stone must first be freed from Chlorides and Fluorides by placing it in a porcelain dish on a sand bath, adding enough strong Sul- phuric Acid to cover it, and heating until white fumes appear. When weighed, r is hung from the balance hook by means of the loop of platinum wire w. Another tube i/, filled with Soda Lime, is attached to the rubber stopper x for the purpose of closing the funnel / and purifying the air, which is afterward drawn through the apparatus. Weigh the absorption apparatus r and connect it with the tubes q and s. After the apparatus is set up, it is tested for leaks as follows: Insert the stopper x in the funnel/, and open the funnel stop-cock. METHODS OF ANALYSIS. 65 Then open the stop-cock v and allow the water to flow freely. A current of air entering at y will pass through the whole apparatus. Bubbles of air will be seen in m, o and r. Close the stop-cock in /, and if all the joints are tight, the bubbling will stop. If any bubbles are seen, it will show that there is a leak in that part of the apparatus, or in the part to the left of it. Weigh .5 gram of the Bicarbonate and brush it into the flask a. Insert the stopper connect g and h and close the stop-cock in /. Into / pour 25 Cc. of water and insert the stopper x. Open the stop-cock V about halfway and the stop-cock in /fully, and permit the water to flow freely into a. Close the stop-cock in /, take out X, and into / pour about 20 Cc. of dilute Nitric Acid. Replace x and open v fully. Open the stop cock in / very cautiously, and permit the acid to enter a. A violent effervescence will ensue, and the liberated Carbon Dioxide (COg) will pass through J, m, o and p and be absorbed by the Soda Lime in r. When the effervescence has subsided, close the stop-cock in / and place the lighted burner d under a. Permit the flame to just touch the bottom of a, and gradually heat to boiling. Allow to boil for about two minutes, and extinguish the flame. Open the stop-cock in / and partly close V, allowing the water to drop rapidly. It will be noticed that the part of the absorption apparatus r which contains the Soda Lime has become quite warm. Continue drawing a current of air through until this last-mentioned tube does not feel warm when touched by the hand. Close v, remove r and insert the caps. Hang it on the balance hook and weigh it. The increase in weight will be the Carbon Dioxide (COg) originally contained in the Bicarbonate. Determination of Alkali, NaaO: Weigh 3.1 grams of the Bicarbonate and brush it into a 100 Cc. Erlenmeyer flask. Add about 20 Cc. of cold water and a drop of Methyl Orange Indicator. Remove to a burette and titrate with Standard Acid, as described under Soda Ash. The number of Cc. and tenths used of the Standard Acid will represent the percentage of Alkali (Na2 0) present. Calculation. Having determined the constituents and impurities of the Bicar- bonate, the next step is to calculate the percentage of actual Sodium 5 H6 CHEMICAL ANALYSIS FOR GLASSMAKERS. Bicarbonate which is available. The method of calculation is best shown by an example. Example of Sodium Bicarbonate Analysis: Determination of Moisture, 10 grams taken: Weight of platinum dish and Bicar- bonate, 45.3983 Weight after first heating, 45.3683 Weight after second heating, 45.3683 Loss of weight, .0300 or 0.3 per cent. HgO. Determination of Sodium Chloride (NaCl), weight taken 2 grams: Standard Silver Nitrate used, 2 Cc. 2 X . 0059 = . 0 1 1 8 ( NaCl ) X 50 = 0. 59 per cent. NaCl. Determination of Sulphate (Na2S04), 5 grams taken: Weight of crucible, cover and BaS04, 34.2900 Weight of crucible and cover, 34.2630 Weight of BaS04, .0270 .0270 X 12.24 = 0.33 per cent. NagSO^. Determination of Water (HjO): Weight of boat and Bicarbonate, 2.9920 Weight of boat, 1.9920 Taken for analysis, 1 gram. Weight of boat and Bicarbonate before heating, 2.9920 Weight after heating, 2.6260 Loss or Water (II2O) plus one-half Carbon Dioxide (CO2), .3660 Weight of Calcium Chloride tube after absorption (e. Fig. 77), 30.8530 Weight before absorption, 30.7450 Increase of weight, or HgO, from Bicarbonate, .1080 Weight of moisture in 1 gram of Bicarbonate, as found above, .0030 Combined water of Bicarbonate, .1050 Loss of weight of boat and Bicarbonate after heating, 0.3660 Water as found above, 0. 1080 Difference or one-half of Carbon Dioxide in Bicarbonate, .2580 .2580 X 2 X 100 = 51.6 per cent. CO2 in Bicarbonate. METHODS OF ANALYSIS. 67 Determination of Carbon Dioxide (CO^), weight taken 0.5 gram: Weight of absorption tube after absorption (r, Fig. 78), 131.5092 Weight before absorption, 131.2512 Increase in weight or CO 2 in Bicarbonate, .2580 .2580 X 2 X 100 = 51.6 per cent. CO2 in Bicarbonate. Determination of Alkali (Na20)2, weight 3.1 grams: Standard Acid used, 36.6 Cc. Alkali (NagO), 36.6 per cent. Summary. Sodium Chloride, NaCl, .59 Sodium Sulphate, Na2S04, .33 Moisture, H2O, .30 Combined Water, H2O, 10.50 Carbon Dioxide, CO 2, 51.60 Alkali, NajO, 36.60 Calculation. First calculate the percentage of Carbon Dioxide due to the Alkali found. Alkali (Na20) : Carbon Dioxide (CO2) : : 36.6: per cent. COj or, supplying the molecular weights: 62 : 44 : : 36.6 : per cent. CO 2 44 X 36.6 ^ 62 = per cent. CO2. CO 2 due to NagO = 25.97 per cent. This result may also be obtained by multiplying the Alkali per- centage by 44 and dividing the result by 62. Subtract the percentage of CO 2 due to Alkali from the total CO 3. as found above. Total CO 2, 51.6, minus CO 2 due to Alkali, 25.97, equals 25.63 per cent. Multiply this by 2, to get the CO 2 due to Bicarbonate. 25.63 X 2 = 51.26 per cent. Calculate this to Bicarbonate: Carbon Dioxide (CO2) : Sodium Bicarbonate (NaHCOg) : : 51.26 : per cent. NaHCOg, or, substituting the molecular weights: 44 : 84 : : 51.26 : per cent. NaHCOg. 84 X 51.26 - 44 = per cent. NaHCOg, or 97.90 per cent. This result may also be obtained by multiplying the percentage of CO 2 due to NaHCOg by 84, and dividing the result by 44. 68 CHEMICAL ANALYSIS FOR GLASSMAKERS. Calculate the CO 2 due to Bicarbonate into terms of Alkali (Na2 0) due to Bicarbonate on the basis that two molecules Carbon Dioxide (or 2 CO2) are equivalent to one of Alkali (NasO), that is, 2 CO2 = Na20, we have the proportion : 2 CO2 : NagO : : 51.26 : per cent. Alkali due to Bicarbonate, or supplying the molecular weights: 88 : 62 : : 51.26 : per cent. Alkali due to Bicarbonate. 62 X 51.26 ^ 88 = 36.11 per cent. NagO due to Bicarbonate. This result is also obtained by multiplying the percentage CO 2 due to Bicarbonate by 62 and dividing by 88. Subtract this from the total Alkali found, 36.6 minus 36.11 equals 0.49 per cent. Alkali (NagO) due to Monocarbonate (NaaCOg). Calculate this into Monocarbonate (Na2C03): Na20 : Na2C03 : : 0.49 : per cent. Na2C03. Supplying molecular weights, 62 : 106 : : 0.49 : per cent. Na2C03 106 X 0.49^62 = 0.84 per cent. Na2C03. Results of Analysis. Sodium Bicarbonate, NaHCO^, 97.90 Sodium Carbonate, Nag CO 3, .84 Sodium Chloride, NaCl, , .59 Sodium Sulphate, Na2S04, .33 Moisture, H2O, .80 99.96 per cent. Condensed Rides for Calculations. 1. Multiply the Alkali (Na20) percentage by 44, and divide the result by 62. This gives the Carbon Dioxide due to total Alkali. 2. Subtract this result from the total Carbon Dioxide, and mul- tiply the remainder by 2. This gives the Carbon Dioxide due to Bicarbonate. 3. Multiply this result by 84 and divide by 44. This gives the percentage of Sodium Bicarbonate (NaHCOg). 4. Multiply the Carbon Dioxide percentage found by Rule 2, by 62 and divide by 88. Subtract the result from the percentage of total Alkali (NagO). This gives the percentage of Alkali due to Monocarbonate. 5. Multiply this result by 106 and divide by 62. This gives the percentage of Monocarbonate (NaaCOg). METHODS OF ANALYSIS. 69 Potash, Potassium Carbonate K^CO^. Determination of Alkali (KjO), and total Potash (K2CO3). Weigh 2 grams of Potash, and brush it into a 120 Cc. Erlen- meyer flask. Add 25 Cc. of cold water and allow to dissolve. Add one drop of Methyl Orange Indicator, remove to a burette and titrate with Standard Acid as described under Soda Ash (page 53). The number of Cc. and tenths of the Acid used, multiplied by .047, and this result multiplied by 50 will be the percentage of Alkali (K2O). The Alkali percentage multiplied by 138 and divided by 94, Avill give the percentage of total Potash (K2CO3). Example, 2 grams taken: Standard Acid used 24.3 Cc. 24.3 X .047 X 50 = 57.1 per cent. Alkah, K2O. 57.1 X 138^94 = 83.82 per cent. Potash, K2CO3. Determination of Water, HgO: Weigh 10 grams into a weighed platinum crucible and place over a Bunsen burner. Allow the flame to just touch the bottom, keeping it red hot for about 15 minutes. Place in a desiccator, and when cool weigh it. Heat again for about 10 minutes, and repeat the weighing. When two weights are obtained which do not differ more than 10 milligrams, consider the loss as Water (H2O). Example, 10 grams taken: Weight of crucible, cover, and Potash before heating, 66.578 Weight after first heating. 65.198 Weight after second heating, 64.918 Loss or Water (H2O), 1.660 grams. 1.660 X 10 = 16.6 per cent. Water (HgO). Determination of Chloride (KCl): Weigh 10 grams, and proceed exactly as described under Soda Ash, determination of Salt (page 55). The number of Cc. and tenths of the Standard Silver Nitrate used, multiplied by .0075, and this result multiplied by 10 will give the percentage of Potas- sium Chloride (KCl) present in the Potash. Example, 10 grams taken: Standard Silver Nitrate, 0.5 Cc. 0.5 X .0075 X 10 = 0.37 per cent. Chloride (KCl). 70 CHEMICAL ANALYSIS FOR GLASSMAKERS. Potassium Nitrate, Saltpeter, KNO^. Determination of Water (HgO): Proceed as directed under Sodium Nitrate, page 61. Determination of Chloride (KCl): Proceed as directed under Sodium Nitrate, page 61, multiplying the Standard Silver Nitrate by .0075, and multiply this result by 20 to get the percentage of Chloride (KCl). LIME. The various kinds of lime used in glass manufacture are: Shell lime, made by burning oyster shells, and water-slaking the quick lime obtained; Stone lime, made by crushing limestone, calcite or marble, and containing, theoretically, 100 per cent. Calcium Car- bonate (CaCOg); Dolomite lime, made by burning dolomite. This last-mentioned variety may contain upward of 40 per cent. Mag- nesia (MgO). Ohio lime is of this kind. Determination of Lime (CaO) and Magnesia (MgO): Weigh 1 gram and brush it into a 150 Cc. beaker. Cover the beaker with a watch glass and add about 50 Cc. of cold water, and then 20 Cc. of concentrated Hydrochloric Acid — adding the acid carefully. When effervescence has ceased, wash off the watch glass into the beaker and carefully boil until dissolved. Add a drop of concentrated Nitric Acid and boil again. Add sufficient strong Ammonia to give a decided odor, boil and filter through a 7 Cm. filter paper into a 200 Cc. graduated flask. Wash three times with hot water, filling the funnel each time. Cool the flask by allowing hydrant water to run over the outside, and when cool, fill to the mark with cold distilled water. Mix well by shaking the flask. With a pipette, take out 50 Cc. and allow it to run into a 200 Cc. beaker. Add a little strong ammonia and heat the contents of the beaker to boiling, and add about 30 Cc. of hot solution of Ammo- nium Oxalate. Stir and boil for two minutes, and set aside to allow the precipitated Calcium Oxalate to settle. When the pre- cipitate has settled clear, filter through an 11 Cm. ashless filter- paper into a 300 Cc. beaker, and wash the first beaker with a jet of hot water making sure to remove all the precipitate to the filter- paper, and using the " policeman " as described on page 17. Wash the filter with hot water until the last drojDS running through show no turbidity when tested with Silver Nitrate. METHODS OF ANALYSIS. 71 Take the filter out of the funnel and place it in a 500 Cc. flask (Fig. 12), and add about 200 Cc. hot water. Carefully pour about 15 Cc. of concentrated Sulphuric Acid into the flask. This is per- formed by adding about 1 Cc. at a time, and shaking the flask at each addition. Remove the flask to a burette and titrate with Strong Standard Permanganate. Add this carefully until one drop gives a decided pink color, which remains for at least five minutes on shaking. The number of Cc. and tenths of Permanganate- used, multiplied by .005, will be the amount of Calcium Oxide (CaO) or Lime present. As 50 Cc. of the solution was taken and this represents 0.25 grams in weight, we multiply the above result by 400 to get the percentage. The precipitate from the Calcium Oxalate contained in the 300 Cc. beaker is allowed to cool. Add sufficient strong Ammonia to give a decided odor, and about 30 Cc. of solution of Sodium Phos- phate and set aside over night. Filter through a 9 Cm. ashless filter-paper, and wash out the beaker with dilute Ammonia (1 to 3 of water). Carefully remove all the precipitate from the beaker and stirring rod, using a policeman. This must be carefully per- formed, as the precipitate adheres very strongly to the sides of the beaker. Wash the filter four times with dilute Ammonia and place the funnel in a drying oven. When dry, remove from the funnel, and allow the precipitate to fall on a piece of glazed paper. Burn the filter-paper on a platinum wire (page 23), and ignite the charred mass in a weighed porcelain crucible. When reduced to ashes allow the crucible to cool and add a drop of strong Nitric Acid. Carefully evaporate with the burner flame and heat until white. Allow the crucible to become cool again, and brush into it the precipitate from the glazed paper. Ignite strongly, cool again, and add a couple of drops of strong Nitric Acid. Evapor- ate carefully to avoid spattering, and ignite until the contents of the crucible are white. Remove to a desiccator and weigh when cool. The weight of the Magnesium Pyro-phosphate (Mg2P207) found, multiplied by .36 gives the Magnesia (MgO) in 0.25 grams of Lime taken for analysis, and this weight multiplied by 400 gives the percentage of Magnesia (MgO). 72 CHEMICAL ANALYSIS FOR GLASSMAKERS. Example I, 100 Cc. of Lime Solution taken equivalent to 0.5 grams Toledo Lime: Strong Standard Permanganate, 28.7 Cc. 28.7 X .005 X 400 = 57.4 per cent. Lime (CaO). Weight of crucible, cover, and MgaPjO^, 28.1050 Weight of crucible and cover, 27.8330 Weight of MgaPaO^, .2720 0.272 X .36 X 400 = 39.168 per cent. Magnesia (MgO). Example II, Burnt Limestone: Strong Standard Permanganate 40.3 Cc. 40.3 X .005 X 400 = 80.6 per cent. Lime (CaO). Weight of crucible, cover and Mg^F^O^, 27.8254 Weight of crucible and cover, 27.8010 Weight of MgsPgO^, .0244 0.0244 X .36 X 400= 3.52 per cent. Magnesia (MgO). Determination of Carbon Dioxide (COg): The apparatus shown in Figure 78 is used in this determination. For a ground Rock-Lime take 0.5 grams, and for a burnt Lime 1 gram. Weigh out the Lime, brush it into the flask a. Weigh the absorption tube r and connect it with q and s. Make all the necessary connections and proceed exactly as described under Sodium Bicarbonate on pages 63 to 85. The increase in weight of the tube r will be Carbon Dioxide. To get the percentage multi- ply by 200 in case of a Limestone, and by 100 in case of a burned Lime. Example, Burned Lime 1 gram taken: Weight of absorption tube after, 66,1383 Weight of absorption tube before, 66.1030 Weight of Carbon Dioxide (CO2), .0353 .0353 X 100 = 3.53 per cent. Carbon Dioxide. Determination of Water, H2O: Weigh 1 gram of the Lime into a weighed platinum crucible. Ignite over a blast lamp until the weight is constant, that is, until the last two weighings do not differ more than 5 milligrams. The METHODS OF ANALYSIS. 73 loss will be Water and Carbon Dioxide. Subtract from this the Carbon Dioxide as found by the foregoing method. The difference will be Water (H2O). Example. Burned Lime, 1 gram taken: Weight of crucible, cover and Lime, 25.2244 Weight after first heating, 25.1684 Weight after second heating, 25.1009 Weight after third heating, 25.1004 Loss of weight, or Water, plus Carbon Dioxide, .1240 Weight of Carbon Dioxide as found before, .0853 Weight of water, -0887 .0887 X 100 = 8.87 per cent. Water (H2O). Determination of Silica, Alumina and Ferric Oxide: Weigh 1 gram of the Lime and brush it into a 100 Cc. beaker. Cover with a watch glass and proceed to dissolve in dilute Hydro- chloric Acid. When dissolved, filter through a 7 Cm. ashless filter-paper into a 200 Cc. porcelain casserole. Wash the beaker onto the filter, and wash the latter three times with hot water. Place the casserole on an air-bath to evaporate. Remove the wet filter-paper from the funnel and place it in a platinum crucible. Ignite over a blast lamp until the paper is reduced to ashes. Then place in the crucible about 1 gram of dry c. p. Sodium Carbonate, and heat until fused. When cool, cover the crucible, add a little water and a few drops of concentrated c. p. Hydrochloric Acid. Keep the cover on while effervescence is noticed and add more acid, a few drops at a time, until the fused mass is dissolved. Pour the contents of the crucible into the casserole, wash the cover and crucible with a jet of hot water, allowing the washings to fall into the casserole. To the solution add a drop of concentrated Nitric Acid and evaporate to dryness. Allow to cool, and add just sufficient dilute Hydrochloric Acid to redissolve. Evaporate again to dryness and redissolve again in dilute Hydrochloric Acid. Filter through all Cm. ashless filter-paper and proceed exactly as de- scribed under Typical Silicate Analysis, on pages 83 and 84, para- graphs 2, 3, and 4. 74 CHEMICAL ANALYSIS FOR GLASSMAKERS. Example of Analysis of Burned Lime: Lime, CaO, 80.60 Ma gnesia, MgO, 3.52 Carbon Dioxide, CO 2, 3.53 Water, U^O, 8.87 Alumina, AljOg, 1.23 Ferric Oxide, FcgOg, .20 Silica, SiOg, L77 99.72 per cent. m H3 MANGANESE. Ores of Manganese are valued according to their oxidizing power, and this is expressed in terms of the Peroxide, or Dioxide (MnOj). To determine the oxidizing power, proceed as follows: Prepare an apparatus, as shown in Fig. 79. The ring stand a supports the 500 Cc. flask b, which is fitted with a rubber stopper c, hav- ing one hole. The bent tube d passes through this hole and dips just below the surface of the water contained in the 50 Cc. beaker e. Pour into the flask about 90 Cc. of c. p. dilute Sulphuric Acid and drop in one gram of piano wire which has been carefully weighed. Insert the stopper and with the burner/ gently heat until the wire is dissolved. Remove the stopper and add 0.5 gram of the finely-powdered sample — of Manganese ore. It is well to have this in a small, wide, glass tube and to drop the tube directly into the flask. Replace the stopper and boil gently until the sample is dissolved. Place the end of the tube d into the water in e and allow the water to recede through d into the flask. The water in e should have been previously boiled to expel any air it may contain. Add a httle more boiled water to e and then add about 200 Cc. of boiled water to the contents of the METHODS OF ANALYSIS. 75 flask a, allowing it to wash down the inner surface of the flask. Remove the flask to a burette and titrate with strong Standard Permanganate. The number of Co. and tenths used, multiplied by .01 will give the amount of iron which remains unoxidized by the Manganese ore, and this deducted from the total Iron (1 gram) leaves the Iron which has been oxidized. This result, multiplied by 87 and divided by 112, will give the amount of Peroxide (MnOj) present in the ore, which multiplied by 200 gives the percentage. The percentage of Peroxide, multiplied by 16 and divided by 87, gives the percentage of available Oxygen. Example, 0.5 gram taken: Iron wire, 1-0000 gram. Strong Standard Permanganate, 47.8 Cc. X .01 = .4780 • Difference, or Iron oxidized by the Manganese ore, .5220 .5220 X = -4055 X 200 = 81.10 per cent. MnO^. 81.1 X If = 14.85 per cent. Available Oxygen. Test for Cobalt in Manganese Ore. Some Manganese ores contain Cobalt and should be rejected, as even a sm.a:ll percentage of this impurity will give a bluish tint to flint glass. To test for Cobalt, dissolve about 1 gram in Hydro- chloric Acid, add a drop of Nitric Acid and boil. Dilute with an equal volume of Water, and make alkaline with Ammonia. Add an excess of Ammonium Sulphide and filter. Heat a platinum wire, with the end bent into a small loop, red hot in a burner flame and dip it in some powdered borax. Heat again, and when the borax is in a glassy bead, touch it to the filter. Place in the flame and fuse the bead. A deep blue color indicates Cobalt. Arsenic or Arseniaus Oxide, Jlsg^s- Weigh 1 gram and brush it into a 500 Cc. graduated stoppered flask. Add about 10 Cc. of Aqua Regia (page 43), and when dis- solved fill the flask to the mark with cold water. Insert the stopper and mix well by shaking. With a graduated pipette re- move 100 Cc. (0.2 grams) and allow it to run into a 200 Cc. beaker. To this add strong Ammonia until a decided odor is pro- duced. Then add about 25 Cc. of Magnesia Mixture (page 49). Stir well and allow to stand for 24 hours. Filter through a 9 Cm. 76 CHEMICAL ANALYSIS FOR GLASSMAKERS. filter-paper, and with a jet of dilute Ammonia (1 in 4) wash all the precipitate on to the filter-paper. The Ammonia used should have a few drops of Nitric Acid added to it. Be sure to get all the precipitate out of the beaker by using a "pohceman." Wash about three times with the Ammonia. When well washed place a weighed porcelain crucible under the funnel, and stir the precipi- tate with a fine jet of dilute Nitric Acid (1 in 2). When the precipitate is dissolved, wash twice with a jet of hot water. Place the crucible on a sand bath and evaporate to dryness. When dry, ignite over a Bunsen burner, gently at first, and then strongly. Remove the crucible and cover to a desiccator, and weigh when cool. The weight of the contents of the crucible. Magnesium Pyro-Arsenate (Mg2As207) multiplied by 197, and divided by 309 gives the weight of Arsenious Oxide (AsjOg), and this mul- tiplied by 500 will give the percentage. Example, 0.2 grams taken: Weight of crucible, cover, and MgaAsjO^, 37.2003 Weight of crucible and cover, 36.8882 Weight of Mg2As207, .3121 .3121 X 1 «| X 500 = 99.45 per cent. AS2O3. LEAD. Litharge, PbO. Red Lead, Pb^O^. Dissolve 0.5 grams in a small beaker in the least possible amount of concentrated Nitric Acid, and add an equal volume of hot water. Filter through a 9 Cm. filter-paper and allow the fil- trate to run into a weighed porcelain crucible. Wash with a jet of hot water until the washings running through the funnel are neutral when tested with Litmus paper. Place the crucible on a sand bath, add about 1 Cc. of c. p. concentrated Sulphuric Acid and evaporate to dryness. When dry, ignite over a Bunsen burner until the contents of the crucible are white. Remove to a desic- cator and weigh when cool. If the sample is Litharge multiply the Lead Sulphate found by 221 and divide by 301, this gives the weight of Litharge (PbO). This weight multiphed by 200 gives the percentage. If the sample is Red Lead multiply the Lead Sulphate found by 0.753. This result multiplied by 200 gives the percentage of Red Lead (Pb304). METHODS OF ANALYSIS. 77 Example, Litharge 0.5 gram taken: Weight of crucible, cover, and PbS04, 15.5371 Weight of crucible and cover, 14.8580 Weight of Lead Sulphate, PbS04, .6791 .6791 X III X 200 = 99.72 per cent. PbO. Barium Carbonate, Baryta, BaCO^. Determination of Total Carbonate (BaCOg). Weigh out 1 gram and brush it into the flask a Fig. 78. Weigh the absorption tube r, and make all necessary connections. Pro- ceed exactly as described on page 65 under Determination of Car- bon Dioxide in Sodium Bicarbonate. The increase in the weight of r, multiplied by 196 and divided by 48, gives the weight of Barium Carbonate (BaCOg). This result multiplied by 100 gives the percentage. Another Method. Based on the precipitation as Barium Sulphate (BaS04), and calculation of the equivalent Barium Carbonate (BaCOg). Weigh 0.5 grams of the sample, and proceed exactly as described under Determination of Salt Cake in Sodium Carbonate (page 55). The weight of the Barium Sulphate found multiplied by 196 and divided by 232 gives the weight of Barium Carbonate (BaCOg), and this result multiplied by 200 gives the percentage. Zinc Oxide. ZnO. Determination of Total Oxide: Weigh 0.5 gram and dissolve it in a 250 Cc. beaker in concen- trated Hydrochloric Acid. Add a couple of drops of concentrated Nitric Acid and heat to boiling. Dilute with an equal quantity of water, add enough strong Ammonia to give a decided odor and boil for a few minutes. This will precipitate any Iron that may be present. Filter through a 9 Cm. filter-paper into a 750 Cc. beaker and wash the filtrate with hot water until the last few drops running through show no reaction when tested with Silver Nitrate. To the filtrate add enough Hydrochloric Acid to give a strong re- action when tested with Litmus paper. Remove the beaker to a burette and titrate with Standard Potas- sium Ferrocyanide. Add the Standard Solution cautiously, and 78 CHEMICAL ANALYSIS FOR GLASSMAKERS. toward the end of the test take out a drop from the beaker with a glass rod and place it in contact with a drop of Uranium Nitrate Indicator, which is on a china plate. A red color shows that the test is finished. It will be noticed in adding the Standard Solu- tion that the precipitate which forms at first is coarse, but on further addition of the Standard Solution it becomes' fine. When this stage is reached, it is time to begin taking out drops to be tested with the indicator. The number of Cc. and tenths of the Standard Ferrocyanide, multiplied by the strength as found per page 39, gives the weight of Zinc Oxide (ZnO) present, and this result, multiplied by 200, will give the percentage. Example, 0.5 grams taken. Standard Ferrocyanide 1 Cc. = 0.1246 gms. Zn: Standard Potassium Ferrocyanide, 39.6 Cc. 39.6 X .01246 X 200 = 98.68 per cent. ZnO. Determination of Moisture, HgO: Weigh 1 gram into a weighed platinum dish, and heat in a drying oven to constant weight, proceeding exactly as described on page 57, in Determination of Moisture in Soda Ash. The loss of weight, multiplied by 100, gives the percentage of Moisture (H,0). Example, 1 gram taken: Weight of whole first, 35.4996 Weight after drying, 35.4866 Loss of weight, .0130 Moisture, 1.8 per cent. FLUORIDES. The Fluorides used in glass-making are two, namely: Fluorspar or Calcium Fluoride (CaF2), and Cryolite. The former is a com- pound of the gas Fluorine (F), with the metal or base Calcium (Ca). The latter is a compound of Fluorine, with the metals or bases Sodium (Na) and Aluminium (Al). Owing to the difficulty experienced in properly estimating the proportion of Fluorine in Fluorides, the methods given below for both minerals can be re- garded only as approximate. METHODS OF ANALYSIS. 79 Fluorspar, Calcium Fluoride, CaF^. Weigh 1 gram into a weighed platinum dish and place on a sand-bath. Add, very cautiously, drop by drop, concentrated c. p. Sulphuric Acid until the mineral is decomposed. Heat on the sand-bath until dry, raising the heat to a dull red until no more white fumes are given off. Remove the dish to a dessicator, and when cool weigh it with contents. The Sulphuric Acid replaces the Fluorine of the Fluoride, forming Calcium Sulphate (CaS04). The weight of the Calcium Sulphate found, multiplied by 78 and divided by 136, gives the weight of Calcium Fluoride (CaFj) present, and this multiplied by 100 gives the percentage. Example, 1 gram taken: Weight of dish and CaS04, 59.3370 Weight of dish, 57.6072 Weight of CaS04, 1.7298 1.7298 X = 99.21 per cent. CaFa. (When treating a Fluoride with Sulphuric Acid, care should be taken to perform the operation in a place where there is a strong current of air, preferably an upward draught, as the liberated Fluorine is dangerous to breathe, and will attack any glass objects in the vicinity. ) Cryolite. Determination of Fluorine (F): Weigh 1 gram and mix it in a weighed platinum crucible with 10 grams of c. p. Calcium Carbonate (CaCOg). Heat for one hour over a Bunsen burner, keeping the bottom of the crucible a dull red. Allow to cool and add hot water; as the mass crumbles wash it into a platinum dish and heat on a sand-bath until it appears decomposed (about a half hour). Filter through all Cm. filter- paper with gentle suction and wash thoroughly with hot water. When all the precipitate has been removed from the dish, place the latter beneath the funnel. Cover the funnel with a watch glass, and cautiously add dilute Acetic Acid (1 in 2), moving the watch glass a little to one side while adding the acid. When the precipi- tate is all dissolved, wash off the watch glass with hot water and wash the filter-paper thoroughly. Remove the dish to a sand-bath and evaporate to dryness, and continue heating until no more odor 80 CHEMICAL ANALYSIS FOR GLASSMAKERS. of Acetic Acid can be perceived. Add a little hot water and filter on a 9 Cm. ashless filter-paper. Wash thoroughly with hot water. Place the wet filter-paper and contents in a weighed platinum crucible, heat gently with a Bun sen burner until the paper is charred, and then strongly until the contents of the crucible are white. Cool in a dessicator and weigh. The weight of the con- tents of the crucible or Calcium Fluoride, multiplied by 38 and divided by 78, gives the Aveight of Fluorine (F) in the Cryolite. Example, 1 gram taken: Weight of crucible and CaFg, 57.9140 Weight of crucible, 56.7938 Weight of CaF 2, 1-1202 1.1202 X .5457 X 100 = 54.57 per cent. Fluorine. If desired, the above result may be checked by adding c. p. con- centrated Sulphuric Acid to the Calcium Fluoride in the crucible, evaporating to dryness and igniting, as described in Fluorspar. The Calcium Sulphate thus found, mAiltiplied by 38 and divided by 136, gives the amount of Fluorine which should agree with the above just found. Determination of Sodium (Na): W eigh 1 gram and proceed exactly as described in paragraph 9 Silicate Analysis on page 85. The Chlorides found are to be con- sidered as Sodium Chloride (NaCl) which when multiplied by 23 and divided by 58 gives the weight of Sodium (Na), this multi- plied by 100 gives the percentage. Example, 1 gram taken: Weight of dish and NaCl, 33.4290 Weight of dish, 32.6197 Weight of NaCl, .8093 .8093 X If = .3209 X 100 32.09 per cent. Na. Determination of Aluminium, Al. Weigh 1 gram, mix it with 5 grams of the Silicate Flux (page 46), Fuse in a platinum crucible. Proceed as described in para- graphs 2 and 4 of Silicate Analysis, pages 83 and 84. The pre- cipitate obtained by precipitation with Ammonia in paragraph 4 is ignited and weighed as Alumina (AlgOg), which when multiplied by 54, and divided by 102, gives the weight of Aluminium (Al). METHODS OF ANALYSIS. 81 Example, 1 gram taken: Weight of crucible, cover, and AI2O3, 37.1020 Weight of crucible and cover, 36.8744 Weight of AI2O3, .2276 •2276 x^Y2- = -1204; .1204x 100=12.04 percent. Aluminium. Summary, of Cryolite Analysis: Fluorine found by Acetic Acid treatment, 54.57 per cent. Sodium found by CaCOg and NH4CI treatment, 32.09 per cent. Aluminium found by fusion with SiHcate Flux, 12.04 per cent. 98.70 per cent. SILICATES. The compounds of Silica (SiO^) which are considered here are: Clay, Fire Brick, Feldspar, Sand and Glass. As similar methods are used in the determination of the constituents of all of the above, a scheme is given for a typical Silicate Analysis, which with variations will serve as a method of analysis for any of the above. Typical Silicate Analysis. Determination of Silica (SiOj), Alumina (AI2O3), Ferric Oxide (FegOg), Lime (CaO), and Magnesia (MgO): 1. Weigh 1 gram of the pulverized sample and mix it thoroughly with 5 grams of SiHcate flux. Place the mixture in a platinum crucible, and by means of a Bunsen burner, heat until all is in a state of quiet fusion and no more bubbles are seen to escape. Grasp the crucible with a pair of tongs (Fig. 38) and dip it in cold water, allowing the water to reach about one-half the height of the cruci- ble and taking care that no water enters. This will cause the fused mass to suddenly cool and shrink away from the crucible, thus loosening it and making it easy to remove. Loosen the mass with the aid of a glass rod and allow it to drop into a 300 Cc. casserole. Add about 100 Cc. of hot water and set the casserole aside. Pour into the crucible about 10 Cc. of dilute Hydrochloric Acid and when the remainder of the fused mass is dissolved, empty the crucible into a small beaker. With a jet of hot water wash the crucible out into this beaker. Cover the casserole with a watch glass and carefully pour into it the solution from the small beaker, taking care that nothing is lost by effervescence. Wash the beaker. 6 82 CHEMICAL ANALYSIS FOR GLASSMAKERS. into the casserole and add to the contents of the latter about 20 Cc. of concentrated Hydrochloric Acid. Place the casserole on a water- bath, or on an air-bath, and heat until all is dissolved. If the sample has been thoroughly pulverized, and the fusion properly conducted, the fused mass will completely dissolve and no floccu- lent particles will be seen floating about, and also there will be no gritty material in the bottom of the casserole. Remove the watch glass, wash it into the casserole with a jet of hot water and evapo- rate the solution to dryness. As it becomes dry, stir it and turn it over with a glass rod, the end of which has been flattened into the shape of a spatula (Fig. 80). When nearly dry, remove from the bath and grind up with a glass pestle. Replace on the bath and allow to come to dryness. When dry, CZZI^ ^ remove again from the bath and grind ■p gQ thoroughly with the pestle. Cover the casserole with a watch glass and place it in a drying oven. Heat with a Bunsen burner and regulate the heat so that the thermometer stands at 120° C, never allowing it to go above 150° C. When the casserole has been in the oven for about half an hour, remove it and allow it to cool. Grind up the contents again and observe if any acid odor is given off. If so, replace in the oven for another half hour. If not, add about 50 Cc. of dilute Hydrochloric Acid, stir with the flattened rod and wash off the rod and pestle with a jet of hot water. Place again on the water-bath or air-bath and heat until all the contents except the Silica is dissolved. Stir with an ordinary glass rod while heat- ing. Filter through a 9 Cm. ashless filter-paper into a 200 Cc. graduated flask. When the casserole has been emptied on to the filter-paper, remove the flask, set it aside and place a 500 Cc. beaker beneath the funnel. Wash the casserole with a jet of hot water, as shown in Figure 25, and remove all the Silica to the filter. Wash off the glass rod, and with a jet of hot water directed around the filter paper, thoroughly wash the Silica. Continue washing until the last drops running through the funnel show no turbidity when tested with Silver Nitrate Solution. Place the wet paper in a weighed platinum crucible, heat over a Bunsen burner, and when the paper is charred, raise the heat and keep the crucible red hot until the Silica is white. Cool in a dessicator and weigh. The weight of the Silica (SiOa) found, multiplied by 100, gives the percentage. METHODS OF ANALYSIS. 83 2. Filtrate from the Silica,: This contains the Alumina (AlgOg), Ferric Oxide (FegOg), Lime (CaO), and Magnesia (MgO). The contents of the 500 Cc. beaker are evaporated to a small bulk, and poured into the 200 Cc. flask. The beaker is Avashed with a jet of cold water into the flask. Then place the flask under a hydrant and allow the water to run over the outside to cool it to 15° C. Fill it to the mark with cold water, insert the stopper and mix by shaking. With a graduated pipette take out 100 Cc. and allow it to run into a 150 Cc. beaker. Pour the rest of the liquid into another 150 Cc. beaker, and wash both the flask and pipette into this last beaker. To each beaker add a drop of Nitric Acid, and heat to boiling. Remove from the heat, and to each add sufficient strong Ammonia to give a decided odor. Boil again for a few minutes, and set the beakers aside for the precipitates to settle. Select ashless filter- papers large enough to take the precipitate, and if necessary use a filter pump (Fig. 35), with the filtering flask and platinum cone (Figs. 30, 31). Filter the contents of both beakers into 200 Cc. beakers, and when all is poured in, substitute two other beakers (250 Cc. ) to receive the washings. Wash thoroughly with hot water, and test the last drops running through the funnels with Silver Nitrate. The washings contained in the 250 Cc. beakers are to be boiled down to a small bulk and added to their respective 200 Cc. beakers containing the filtrates. 3. Determination of Ferric Oxide (FcaOg): Place a 100 Cc. Erlenmeyer flask under one of the funnels, and pour on the filter-paper about 25 Cc. of dilute c. p. Sulphuric Acid (1 in 5). This will dissolve the precipitate on the filter- paper. Wash three times with hot water. Place in the flask a piece of platinum foil in contact with a piece of c. p. stick Zinc. Allow the flask to stand about one hour and then empty it into a 200 Cc. beaker, keeping the Zinc and platinum foil in the flask. Wash out the flask with a little cold water, and pour the washings into the beaker. Place the beaker under a burette and titrate with Weak Standard Permanganate. The number of Cc. and tenths used, multiphed by .0014 gives the Ferric Oxide, this is to be multiplied by 2, because we divided our previous solution (para- graph 1) into two parts. The number of Cc. and tenths multi- phed by .00128, and this result multiphed by 200 gives the per- 84 CHEMICAL ANALYSIS FOR GLASSMAKERS. centage of Ferrous Oxide (FeO), in case the Iron is present in that form. 4. Determination of Alumina (AlgOg): Place the filter-paper and contents from the other funnel in a weighed platinum crucible, burn off the paper, and ignite. Cool in a desiccator and weigh. The contents of the crucible will be Alumina and Ferric Oxide. Subtract the Ferric Oxide as found in paragraph 3, and multiply the result by 200. This will give the percentage of Alumina (AlgOg). 5. Determination of Lime (CaO): We have two 200 Cc. beakers to which have been added the washings from the Alumina and Ferric Oxide precipitates (para- graphs 3 and 4). Pour them into a larger beaker and wash the 200 Cc. beakers into it. Add enough strong Ammonia to give a decided odor, boil and add about 15 Cc. of hot Ammonium Oxalate solution. Proceed as directed under Lime Analysis (page 70). The number of Cc. and tenths of Strong Standard Permanganate used multipHed by .005, and this result multiplied by 100 gives the percentage of Lime (CaO). 6. Determination of Magnesia (MgO): To the filtrate from the Calcium Oxalate precipitate, obtained in paragraph 5, add 1 Cc. of strong Nitric Acid, and evaporate to about 150 Cc. Then add enough strong Ammonia to give a de- cided odor, and about 10 Cc. of Sodium Phosphate. Set aside overnight, and proceed as directed in Lime Analysis (page 71). The MggPaO^ found, multiplied by 0.36, and this result by 100, gives the percentage of Magnesia (MgO). Determination of the Alkalies, Soda (NaaO), and Potash (KgO) : 7. The Silicate is decomposable, and the Sihca may be expelled by Hydrofluoric and Sulphuric Acids. Weigh 1 gram into a platinum dish, and cover it with a httle water. Add drop by drop — stirring at the same time with a plat- inum wire — sufficient Hydrofluoric Acid to dissolve it, and then add a few drops of Sulphuric Acid. Evaporate to dryness on a sand bath, and heat 'over a Bunsen burner until no more white fumes are seen. Add about 5 Cc. strong Hydrochloric Acid, and boil until dissolved. Then add 10 Cc. of solution of Barium Chloride, and filter through a 11 Cm. filter-paper, allowing the filtrate to run into a 50 Cc. beaker. Wash thoroughly with hot METHODS OF ANALYSIS. 85 water. To the filtrate in the beaker add strong Ammonia and Ammonium Carbonate. Boil for a short time and filter into a platinum dish. Wash with hot water. Evaporate the filtrate in the dish to dryness, and heat over the flame until no mere white fumes of Ammonium Chloride are given off. Dissolve in a little hot water, and add about 10 Cc. of Ammonium Carbonate and filter into a weighed platinum dish. Wash with hot water, and evaporate to dryness, heat over the direct flame to drive away all Ammonium Chloride, place in a dessicator and weigh when cool. The contents of the dish are Sodium Chloride and Potassium Chloride. In heating the dish over the direct flame, be careful to apply the heat gradually or the contents of the dish will spatter and thus cause loss. 8. Dissolve the Chlorides in the dish in the least possible quan tity of hot water and add an equal volume of Platinic Chloride Solution. Place the dish on a water-bath and evaporate until the contents are nearly dry. Remove from the bath and allow them to dry spontaneously. Filter through a weighed Gooch crucible (Fig. 32) and wash with dilute Alcohol (1 in 2) until the washings running into the filtering flask are colorless. Place the Gooch crucible in a drying oven heated to 100° C. (not over) and when dry, remove to a dessicator and weigh. The contents of the Gooch crucible are Potassium Platinic Chloride (KgPtClg). The weight of the KjPtCle, multiphed by 148 and divided by 482, gives the weight of Potassium Chloride (KCl), this is to be subtracted from the weight of the mixed Chlorides obtained according to paragraph 7, and the result will be Sodium Chloride (NaCl). The weight of the NaCl just found, multiplied by 62 and divided by 116, gives the weight of Soda (NajO), and this multiplied by 100, gives the percentage. The weight of the K2PtCl6, multiplied by 94 and divided by 482, gives the weight of Potash (KgO), and this mul- tiplied by 100 gives the percentage. 9. The Silicate is undecomposable by treatment with Hydro- fluoric and Sulphuric Acids. Method of J. Lawrence Smith : Weigh 1 gram of the finely-pulverized sample and place it on a sheet of black glazed paper. Grind up 1 gram of c. p. Ammonium Chloride and mix it on the paper with the sample. When well mixed, add about 8 grams of c. p. Calcium Carbonate and mix all 86 CHEMICAL ANALYSIS FOR GLASSMAKERS. together very thoroughly. It is well to add the Calcium Carbonate a little at a time to insure a perfect mixture. Brush the whole into a platinum crucible, place the cover on and heat over a Bun- sen burner. Heat very gently, just keeping the bottom red hot. When no more white fumes are given off raise the heat, so that the flame plays on the lower half of the crucible and continue thus for an hour. Allow the crucible to cool and remove the semi-fused mass with a glass rod, letting it fall into a 300 Cc. casserole. Wash off the cover and wash the crucible into the casserole, using a jet of hot water. Add enough hot water to make the volume about 50 Cc. and place the casserole on a water-bath. Cover it with a watch glass and heat for about a half hour. The mass will slake and crumble, and the alkalies will go into solution as chlorides. (In case the mass fuses together when in the platinum crucible, do not use force in detaching it, but place the crucible and cover in the casserole and add the hot water. ) After heating on the water-bath, allow to stand over night. If in a hurry, proceed at once. Filter through a 11 Cm. filter-paper into a platinum dish and wash with hot water until no reaction is observed with Silver Nitrate Solution. To the filtrate in the dish add 25 Cc. of Ammo- nium Carbonate Solution and evaporate on the water- bath until the volume is about 20 Cc. Add 15 Cc. more of Ammonium Carbon- ate Solution and filter into a beaker. Wash three times with hot water, and to the filtrate in the beaker add 15 Cc. of Ammonium Carbonate Solution. Filter into a weighed platinum dish and when this dish is three-quarters full, substitute a beaker and place the dish on a water-bath. As the contents evaporate, add more fil- trate, until the solution has all been filtered. Wash three times with hot water and pour the washings into the platinum dish. Evaporate to dryness and ignite, as described in paragraph 7. Weigh the dish and contents to get the weight of the mixed chlor- ides of Sodium and Potassium. Then finish exactly as directed in paragraph 8. Clay Analysis. Determination of Moisture: Weigh 1 gram into a weighed platinum dish, place it in a dry- ing oven heated to 100° C. and proceed exactly as described in Soda Ash analysis, p. 57. Determination of Combined Water: Weigh 1 gram into a weighed platinum crucible, place over a METHODS OF ANALYSIS. 87 blast lamp and ignite to constant weight exactly as described in Lime analysis, page 72, and deduct the percentage of moisture as found above. Determination of Silica, Alumina, Feriic Oxide, Lime and. Mag- nesia: Proceed exactly as described in Typical Silicate Analysis, para- graphs 1, 2, 3, 4, 5 and 6. The Alumina precipitate, paragraph 2, will be large and difficult to properly wash. It should be poured, a little at a time, on the filter-paper, using a strong suction from the filter pump. Get as much as possible of the supernatant liquid from the beaker before pouring on the precipitate. When all is on the filter-paper, shut off the suction, fill the funnel with hot water, allow it to stand a minute and then remove the suction. Use a " policeman " to get the precipitate from the beaker. In some clays, generally the light-colored ones, the Iron is pres- ent in the Ferrous state, and should be reported as Ferrous Oxide (FeO). Determination of the Alkalies, Soda and Potash: Proceed exactly as directed in paragraph 9. Examples of Clay Analysis: China Clay or Kaolin. German Pot Clay. Per cent. Per cent Silica, SiOa, 45.55 Silica, Si02, 68.60 Alumina, AlgOg, 39.18 Alumina, AI2O3, 20.64 Soda, NajO, .53 Ferrous Oxide, FeO, .95 Potash, K2O, 2.09 Lime, CaO, .52 Combined Water, HgO, n.29 Magnesia, MgO, .11 Moisture, HjO, .81 Soda, Na20, .99 Potash, K2O. .32 99.45 Combined Water, HgO, 7.75 99.88 In judging the value of Clay from an analysis, the purpose for which it is intended must be borne in mind. When Clay is used as a constituent of the batch, as in the case of Opal glass made from Kaolin, the presence of Alkalies is not deleterious, but that of Iron in any form is objectionable. Where clay is used subjected to furnace heat, as in the form of fire brick, etc., the valuable con- stituents are Silica and Alumina. The others, Lime, Magnesia, Iron, and the Alkalies should be of as low percentage as possible because they are fluxes. CHEMICAL ANALYSIS FOR GLASSMAKERS. Fire Brick. Determination of Silica, Alumina, Ferric Oxide, Lime and Magnesia: Proceed exactly as directed in Typical Silicate Analysis, para- graphs 1 to 6 inclusive. Determination of the Alkalies : For a Silica brick proceed according to paragraphs 7 and 8, for an Alumina brick according to paragraph 9. Examples of Fire Brick Analysis: Silica Brick — Abernnant Brand. Per cent Silica, SiOg. 9L90 Alumina, AlgOg, 3.31 Ferric Oxide, FcgOg .53 Lime, CaO, 2.35 Magnesia, MgO, .29 Soda, NagO, .77 Potash, K2O, .36 99.51 Alumina Brick — Queen's Eun Brand. Per cent. Silica, SiOg, 52.17 Alumina, AlgOg, 45.58 Ferric Oxide, FcgOg , none Lime, CaO, none Magnesia, MgO none Soda, NagO, .84 Potash, K2O, .97 99.56 Feldspar. Determination of Silica, Alumina, Ferric Oxide, Lime and Mag- nesia: Proceed exactly as directed in Typical Silicate Analysis, para- graphs 1 to 6, inclusive. Determination of the Alkalies: Proceed as directed in paragraph 9. Determination of Combined Water: Weigh 1 gram of the finely-pulverized mineral into a weighed platinum crucible and ignite over a blast lamp to constant weight. Example of a Feldspar Analysis: Silica, SiO,2, 59.20 per cent. Alumina, AI2O3, 18.00 " Ferric Oxide, FcgOg, none. Soda, NagO, 4.77 " Potash, K2O, 9.48 " Combined Water, R^O, 8.75 " 100.20 " METHODS OF ANALYSIS. 89 Sand. The impurities to be determined are Alumina (AI2O3), Iron as Ferric Oxide (Fe203), Moisture (H^O) and Organic Matter. Sand may be analyzed according to Typical Silicate Analysis, paragraphs 1 to 4 inclusive, but owing to the large proportion of Silica (SiOj) and the small proportion of the impurities, this method is liable to error, unless performed by a skilled operator. It is customary to determine the impurities and subtract their sum from 100 and call the difference Silica. Determination of Alumina and Ferric Oxide : Finely pulverized so that no gritty particles remain when tested by rubbing with the finger. Weigh 2 grams into a platinum dish and add enough cold water to cover the sand. Add, drop by drop, sufficient Hydrofluoric Acid to dissolve, stirring at the same time with a platinum wire. Add a few drops of Sulphuric Acid and evaporate to dryness on a sand-bath. Heat over the naked flame until all white fumes have ceased coming off. Add about 5 Cc. concentrated Hydrochloric Acid and one drop of concentrated Nitric Acid and boil until the contents of the dish are dissolved. Pour into a 50 Cc. graduated liask and wash the dish into the flask with cold water. Cool the flask by running hydrant water over the outside and fill to the mark with cold water. Insert the stopper and mix by shaking. With a 25 Cc. pipette take out that volume and run it into a 50 Cc. beaker. Empty the flask into a similar beaker and wash it and the pipette into this last beaker, using hot water. Precipitate the Alumina and Ferric Oxide with strong Ammonia, as described in paragraph 2, and determine them according to paragraphs 3 and 4. In determining the Ferric Oxide, use Weak Standard Perman- ganate. Determination of Moisture (H2O): Weigh 5 grams of the sand (not pulverized) into a weighed platinum dish and heat in a drying oven at 100° C. to constant weight. The loss of weight will be moisture, which, multiplied by 20, will give the percentage. Determination of Organic Matter: Weigh 5 grams (not pulverized) into a weighed platinum cruci- ble. Ignite for 15 minutes over the blast lamp. Cool in a dessi- cator and weigh. The loss of weight will be organic matter plus 90 CHEMICAL ANALYSIS FOR GLASSMAKERS. moisture. Subtract the moisture as found above. The difference, multiphed by 20, will give the percentage of organic matter. Simple Tests. Examine the sand with a lens. The grains should be sharp. Bubbles in the grains are not objectionable, as they contain gas — probably COg — Avhich expands Avhen the sand is heated, thus splitting up the grains and promoting fusion. The sand should be colorless and remain so after heating. Ignite a little in a platinum crucible and examine again Avith the lens. It should not become colored, as this indicates the presence of oxidizable impurities, as Iron, etc. Iron may be present as Ferrous Silicate, Ferric Silicate, Magnetic Oxide (Fe304), and in some sands, as the mineral Mennacanite. The Silicate of Iron cannot be dissolved out. The Magnetic Oxide may be removed by treat- ment in a magnetic separator. When sand is treated Avith Hydrochloric Acid it shjould not effervesce, as this Avould indicate the pres- ence of carbonates, as Lime, etc. Sand should be entirely free from Cobalt compounds. These may be tested for by placing the finely-ground sand in a platinum crucible, adding Avater, Hydrofluoric T.^.SOA. Sulphuric Acids, evaporating to dryness, igniting, to drive off all the Avhite fumes, and then adding a little Borax and fusing to a glassy mass. If Cobalt is present, the mass will be of a deep blue color. To determine if a sand has been properl}' Avashed, place a little in a test tube (Fig. 80 A) and half fill the tube Avith cold water. Place the thumb on the open end and shake vigorously. Allow the sand to settle. The clay present Avill remain suspended in the water. The greater the amount of clay present the more turbid Avill the water appear. Example of a Sand Analysis. Juniata Sand, 2 grams taken, treated with HF and H2SO4, ignited, and residue dissolved in HCl. Solution divided into tAvo parts, each equivalent to 1 gram. METHODS OF ANALYSIS. 91 Determination of FegOg: Weak Standard Permanganate, 0.3 Co. 0.3 X .0014 -.00042 .00042 X 100=^.042 per cent. Fe^O^. Determination of AlgOg. Weight of crucible, cover, Al203 + Fe203, 43.71660 W^ eight of crucible and cover, 43.71580 Weight of AI2O3 + Fe203, .00080 Weight of Fe203 found above, .00042 Weight of AI2O3, .00038 .00038 X 100 = .038 per cent. AI2O3. Determination of Moisture (HgO), 5 grams taken: Weight of dish and sand before drying, 23.5892 Weight after drying, 23.5871 Loss of weight, or Moisture, .0021 .0021 X 20 = .042 per cent. HgO. Determination of Organic Matter, 5 grams taken: Weight of crucible and sand before igniting, 48.7162 Weight after igniting, 48.7070 Loss of weight, or Moisture plus Organic Matter, .0092 Moisture as found above, .0021 Difference, or Organic Matter, .0071 .0071 X 20 -=.142 per cent. Organic Matter. Summary. Silica, SiOg — by difference, 99.736 per cent. Alumina, AlgOg, .038 Ferric Oxide, Yq^O^, .042 Moisture, H2O, .042 Organic Matter, .142 100.000 Glass Analysis. Break the glass up in a steel mortar (Fig. 6) and empty the 92 CHEMICAL ANALYSIS FOR GLASSMAKERS. mortar into a porcelain dish. Pass a magnet through the broken glass to remove any particles of steel abraded from the mortar. Finish the pulverization in an Agate mortar (Fig. 4) getting the powder to the consistency of flour, having no gritty particles that may be felt by the finger. Place the powder in a porcelain dish, and dry in an oven for about a half-hour. When dry place it in a tightly stoppered vial (Fig. 10). Use this dried sample for the analysis, taking care to keep the vial tightly stoppered when not in use, as powdered glass absorbs moisture from the air. Determination of Silica, Alumina and Ferric Oxide, Lime and Magnesia : Proceed exactly as directed in Typical Silicate Analysis, para- graphs 1 to 6 inclusive. Unless it is desired to find the percent- ages of Alumina and Ferric Oxide separately, omit the division into two parts of the filtrate from the Silica, paragraph 2, and omit also the determination of Ferric Oxide, paragraph 3, proceed- ing directly to paragraph 4, determining the AljOg and FcjOg together, and multiplying their combined weights by 100 to get the percentage. Determine Lime and Magnesia as directed in paragraphs 5 and 6. * Determination of the Alkalies, Soda and Potash: Proceed according to paragraphs 7 and 8. Examples of Glass Analysis. Common Bottle-Glass: Silica, SiOa, 71.50 1.24 11.35 15.98 Alumina and Ferric Oxide, AljOg -f FcjO 3) Lime, CaO, Soda, NajO, 100.07 per cent. Lime Flint-Glass: Silica, SiOg, 73.68 2.07 3.85 2.78 17.34 Alumina and Ferric Oxide, AljOg + FegO Lime, CaO, Magnesia, MgO, Soda, NagO, 99.72 per cent. METHODS OF ANALYSIS. 93 Bohemian Glass: Lime, CaO, Soda, NajO, Potash, K2O, Silica, SiOj, Alumina and Ferric Oxide, AljOg + FcgO 3) 72.22 1.46 7.98 9.53 8.32 99.51 per cent. Lead Glass. Determination of Silica (SiOg), Lead Oxide (PbO), Alumina and Ferric Oxide (AljOg + FcgOg). Proceed as directed in Typical Silicate Analysis, paragraph 1, using Nitric Acid instead of Hydrochloric Acid to dissolve the fused mass. Evaporate the Nitric Acid solution to dryness, break up the residue in the casserole with the glass rod (Fig. 80), and redissolve in the smallest sufficient quantity of strong Nitric Acid. Evaporate again to dryness to render the Silica (SiOg) insoluble. Add about 50 c.c. of dilute Nitric Acid, heat on the air or water bath with constant stirring. Filter through a 11 cm. ashless filter paper. Wash the filter thoroughly with hot water. Remove it to a weighed platinum crucible. Ignite over a blast lamp until the contents are white. Remove the crucible to a dessicator and weigh when cool. Then add a little water to the contents of the crucible, some Hydrofluoric Acid, and a few drops of c. p. strong Sulphuric Acid. Evaporate carefully over a Bunsen burner, and when white fumes have ceased to come off, raise the heat and con- tinue heating until the contents of the crucible are white. Cool and weigh again. The loss of weight will be Silica (SiOj). Set the crucible aside for the present. To the filtrate from the Si02 precipitation add c. p. strong Sul- phuric acid until no more precipitate forms. Boil gently and filter through a weighed Gooch crucible (Fig. 33) prepared as described on page 20. Wash with hot water until the washings are neutral to litmus paper. Ignite over a Bunsen burner, cool, and weigh. This gives the weight of Lead Sulphate (PbS04) which multiplied by 221 and divided by 301 gives the weight of Lead Oxide (PbO). To the contents of the platinum crucible which contains the res- idue from the Silica determination, add a little Silica flux (page 94 CHEMICAL ANALYSIS FOR GLASSMAKERS. 46) and heat to fusion. Dissolve in a little dilute Hydrochloric Acid and add this solution to the filtrate from the Lead Sulphate precipitation, and treat this combined solution according to para- graphs 2, 8, and 4. Determination of Soda and Potash. Treat the glass according to paragraph 7, and ignite as usual until all the white fumes are driven off. Add about 10 c c. of dilute Hydrochloric Acid, boil for a short time and filter through a weighed Gooch crucible as described above. Wash Avith hot water, add Barium Chloride solution to the filtrate, and from this point proceed according to paragraph 7, to determine the Alkalies. Note. — The Gooch crucible and contents may be weighed and the previous determination of Lead Oxide verified. Example, 1 gram taken: Determination of Silica (Si02). Insoluble matter from paragraph 1, ignited and weighed in a platinum crucible, treated with HF and H2SO4, ignited and weighed again. Weight before adding HF and H2SO4, 56.1526 Weight after adding HF and H2SO4, 55.4448 Loss of Weight or Silica (SiOg), .7078 . 7078 X 100 = 70. 78 per cent. SiO 2 . Filtrate from above precipitated with H2SO4, filtered, ignited, and weighed in Gooch crucible. Weight of crucible and contents, 49.0213 Weight of crucible, 48.8329 Weight of Lead Sulphate (PbS04), .1884 .1884 x|2i = .1383; .1383 X 100 = 13.83 per cent. PbO. Filtrate from paragraph 1. Weight of whole, 55.4125 Weight of crucible, 55.4082 Weight of AI2O3 + FcjOg, .0043 .0043 X 100 -=0.43 per cent. AI2O3 + Fe203. METHODS OF ANALYSIS. 95 Paragraph 7. Determination of the Alkahes, Potash and Soda, 1 gram taken: Weight of platinum dish and chlorides, 50.3457 Weight of platinum dish, 50.0925 Weight of chlorides (KCl and NaCl), .2532 Weight of Gooch crucible and KaPtClg, 42.8356 Weight of Gooch crucible, 42.5836 Weight of KaPtCle, .2520 0. 2520 xA|f = .0774 KCl. 0.2520 X = .0491 K2O; .0491 x 100 = 4.91 per cent. Potash. Weight of chlorides as found above, .2532 Weight of KCl as found above, .0774 Weight of NaCl, . 1758 ,175s XxVe =-0939; .0939 x 100 = 9.39 per cent. Soda. Simmary. Silica, Si02, 70.78 Lead Oxide, PbO, 13.83 Alumina and Ferric Oxide, AI2O3 + FcaOg, .43 Potash, K2O, 4.91 Soda, Na2 0, 9.39 99.34 per cent. Baryta Glass. Determination of Silica (Si02): Proceed as directed in Typical Silicate Analysis, paragraph 1. Determination of Barium Oxide (BaO): Boil the filtrate from the Silica and add about 1 Cc. of hot dilute Sulphuric Acid. Filter, ignite and weigh the precipitated Barium Sulphate. Multiply its weight by 152 and divide by 232 to get the weight of Barium Oxide. This multiplied by 100 gives the per- centage. Determination of AljOg and FcjOg: Add strong Ammonia in excess to the filtrate from the Barium Sulphate precipitation; boil, filter off the Aluminium and Ferric 96 CHEMICAL ANALYSIS FOR GLASSMAKERS. Hydroxides, ignite in a weighed porcelain crucible and weigh. The weight of AlgOg +Fe203, multiphed by 100, gives the per- centage. Determination of Alkalies: Proceed as directed in paragraph 7. Boil the insoluble residue left after treatment with HF and H2SO4 in dilute Hydrochloric Acid. Filter, and if desired, ignite and weigh the filter — which is Barium Sulphate — to check the former Barium Oxide determin- ation. The filtrate is then treated according to the remainder of paragraphs 7 and 8. Zinc Glass. Determination of Silica (SiOg): Proceed according to paragraph 1, Typical Silicate Analysis. Determination of AI2O3 and Fe^Og-. Add to the filtrate from the Silica just enough c. p. dry Sodium Carbonate to make it neutral to Litmus paper. Heat to boihng and while boiling add 10 Cc. of Sodium Acetate Solution. Boil for a few minutes, filter, wash, dry, ignite in a weighed porcelain crucible and weigh as AI2O3 + Fe203. Determination of Zinc Oxide (ZnO): ■ To the filtrate obtained from the AlgOg +Fe203 precipitation, add sufficient Acetic Acid to give a slight odor. Boil, and while boiling, pass Hydrogen Disulphide gas tbrough the solution for about a half hour. Filter off the precipitated Zinc Sulphide, wash it with hot water. Ignite it in a weighed porcelain crucible and weigh as Zinc Oxide (ZnO). Determination of Lime and Magnesia: Boil the filtrate from the Zinc precipitation until the odor of H2S has gone and proceed as directed in paragraphs 5 and 6. Determination of the Alkalies: Proceed according to paragraph 7, but before adding Ammonium Carbonate, add Ammonia and Ammonium Sulphide, to precipitate the Zinc. Then filter this off, wash with hot water, boil the filtrate, add Ammonia and Ammonium Carbonate and continue as directed in paragraphs 7 and 8. METHODS OF ANALYSIS. 97 Example of a Zinc Glass Analysis. Silica, SiOa, 71.12 Alumina and Ferric Oxide, AlgOg + FcgOg, 1.03 Zinc Oxide. ZnO, 2.38 Lime, CaO, 5.65 Magnesia, MgO, 3.43 Soda, NagO, 16.83 100.44 per cent. Determination of Manganese Oxide in Glass: Precipitate the AlgOg and FcjOg with Sodium Acetate, as directed in Zinc Glass, filter them off and wash with hot water. Boil the filtrate, and while boiling, add a few drops of Bromine. Continue boiling and stirring for a short time. The Manganese wall separate as MnOa- Filter it off. Wash with hot water, ignite in a weighed porcelain crucible and weigh as Mn304, which, mul- tiplied by 211 and divided by 227, gives the weight of MnO. Calculation of Recipe from the Analysis of Glass. Suppose, for example, we take the analysis of common bottle glass, given on page 92. The ingredients to be considered are Silica 71.5 per cent.. Lime 11.35 per cent, and Soda 15.98 per cent. Multiply each percentage by 100 and divide the result by the percentage of Silica: Silica, 71.5 x 100 71.5 = 100 parts. Lime, 11.35 X 100^71.5= 15.9 parts. Soda, 15.98x100-^ 71.5= 22.3 parts. Convert the constituents into the equivalent raw materials. This is done by means of knowledge gained from previous analysis of the raw materials to be used. Silica may be considered as Sand, 100 parts. Lime (CaO) must be converted into either Carbonate (CaCOg) or Hydroxide (Slaked Lime), Ca(0H)2. To convert the CaO into CaCOg, multiply by 100 and divide by 56. Example: CaO, 15.9 X 100 - 1590 + 56 - 28.4 parts. To convert the CaO into Ca(0H)2, multiply by 74 and divide by 56. 7 98 CHEMICAL ANALYSIS FOR GLASSMAKERS. Example: CaO, 15.9x74 = 1176.6-^66 = 21 parts. If Soda Nitrate has been used in the glass, part of the NagO will be due to it, and as there is no method for determining the per- centage of NajO due to the Nitrate originally used, the glassmaker must deduct from the proportion of NagO the amount of NagO in the usual amount of Nitrate that he is accustomed to employ. To find the percentage of Soda (Na20) in a given amount of Nitrate (NaNOg), multiply this amount by 62 and divide by 170. Example: Suppose 5 parts of Nitrate were to be used, 5 x 62 = 310 ^ 170 = 1.8 parts NagO, to be deducted from the NaaO found by the an- alysis, we have 22.3-1.8 = 20.5 parts NagO due to Soda Ash. Calculate this to Sodium Carbonate, multiply by 106 and divide by 62: 20. 5 X 106 = 2373-^62 = 36.8 parts NaoCOg. Asc. p. Sodium Carbonate contains 58.49 percent. Soda (NagO), we may consider the 36.8 as 37 parts of 58 per cent. Soda Ash. If the Soda Ash to be added is 48 per cent., we may increase the 36.8 per cent, by 10 per cent., as 36.8 + 3.7 — 40.5 parts of 48 per cent, ash. The calculation may be summed up as follows: Sand, 100 Sand, 100 Soda Ash, 48 per cent., 40 Soda Ash, 48 per cent., 40 Lime Carbonate, 28 Slaked Lime, 21 Nitrate, 5 Nitrate, 5 The calculation will only give an approximate recipe, the final correct recipe must be obtained by the glassmaker' s knowledge of his art. Batch Analysis, A rapid approximate method for determining the proportions of a simple batch (A. H. Elliott): Weigh 10 grams of the batch into a weighed 250 Cc. graduated flask. Add about 100 Cc. of cold water and shake well. Allow the flask to stand about half an hour, shaking at intervals. Fill to the mark with cold water, insert the stopper and mix well by shaking. Allow to settle. Take out 25 Cc. of the supernatant liquid with a graduated pipette and allow it to run through a filter- METHODS OF ANALYSIS. 99 paper into a 100 Cc. Erlenmeyer flask. Wash the filter twice with hot water. Remove the Erlenmeyer flask to a burette, add a drop of Methyl Orange Indicator and titrate with Standard Acid as in Soda Ash Analysis, page 53. The 25 Cc. taken, being one-tenth of the original volume, contains the Soda Ash in 1 gram of the batch. The number of Cc. and tenths of the Standard Acid used, multi- plied by .053, aVid this result by 100, gives the percentage of 58 Soda Ash present. Pour the contents of the 260 Cc. graduated flask through the same filter into another flask and set this filtrate aside, to be used in case another or check determination of Soda Ash is to be made. Place a beaker under the funnel and pour a little hot water into the 250 Cc. graduated flask. Shake it with a rotary motion and then allow the sand to settle. Pour this water into the funnel, keeping the sand in the flask. Repeat this washing twice. Then wash the filter-paper by filling the funnel twice Avith hot water. Remove the beaker from beneath the funnel and substitute for it the 250 Cc. graduated flask. With a pipette, allow 60 Cc. of Stand- ard Acid to run on the filter-paper and when this has passed into the flask, make a hole in the bottom of the paper with a glass rod and with hot water wash the contents of the paper down into the flask. Shake the flask until effervescence has ceased, and when the Lime has dissolved, fill the flask to the mark with cold water. Insert the stopper and mix by shaking. Allow the sand to settle and take out with a pipette 100 Cc. of the supernatant liquid and run it into a 250 Cc. Erlenmeyer flask. This 100 Cc. contains the Lime in 4 grams of the batch. Add a drop of Methyl Orange In- dicator to the flask, place the flask under a burette and run in enough Standard Sodium Carbonate Solution to cause the pink color just to appear. The number of Cc. and tenths of Standard Sodium Carbonate subtracted from the volume of Standard Acid (60xy\=24 Cc. used in the 100 Cc. taken) leaves the volume of Acid neutralized by the lime in 4 grams of batch. This volume of Acid, multiplied by .028, gives the amount of Lime in the 4 grams, and this last result, multiplied by 25, gives the percentage of Lime. Pour the liquid from the flask slowly and carefully without allowing any of the sand to escape. Half fill the flask with hot water, gently shake with a rotary motion. Allow to settle, and pour out the liquid as before. Repeat this washing of the sand. 100 CHEMICAL ANALYSIS FOR GLASSMAKERS. Place the flask in a drying oven, heated to 100° C, and allow it to remain until the sand is dry, then remove it and insert a glass tube; apply the mouth to the upper end of this tube, and suck out the steam. Allow the flask to cool, and weigh it. Deduct the weight of the flask. The difference will be the weight of the sand in the 10 grams of the batch taken. Multiply this by 10 to get the percentage. Example of a Batch Analysis, 10 grams taken: 25 Cc. of Solution containing Soda Ash in 1 gram of Batch. Standard Acid used 4.6 Cc. 4.6 X .053 = .2438 x 100 = 24.38 per cent. Soda Ash. 60 Cc. of Standard Acid used to dissolve the Lime in 10 grams of Batch. 100 Cc. of the total solution, equal to 4 grams of Batch, containing y%- of 60 Cc. or 24 Cc. Standard Acid, 24. Cc. Standard Sodium Carbonate, 14.3 Cc. Difference, or Standard Acid used for Lime in 4 grams of Batch, 9.7 Cc. 9.7 X. 028 = .2716x25 = 6.79 per cent. Lime (CaO). Weight of flask and sand, 45.188 Weight of flask 39.028 Weight of Sand, 6.160 6.16x10 = 61.60 per cent. Sand. Calculation of Batch. Proceed as directed on page 97. Sand, 61.6 x 100 ^ 61.6 = 100 parts. Soda, 24. 38 X 100 61. 6 = 39 parts. Lime, 6.79x100-^61.6= 11 parts. The Lime may be calculated into Carbonate or Hydroxide as directed on page 97. FUEL ANALYSIS. Coal, Proximate Analysis. Extract from the report of the Committee on Coal Analysis of the American Chemical Society, published December, 1899: Sampling. — In sampling from cars proceed as follows: Beginning at one corner of the car drive a scoop-shovel vertically down as METHODS OF ANALYSIS. 101 deep as it will reach. Bring it out with all the coal it will hold, and throw^ into a cart or wheelbarrow. Repeat, taking six scoop- fuls along one side of the car, at equal intervals, six through the center, and six along the other side. Place the coal taken on a close, tight floor. Break all lumps larger than an orange. Mix by shoveling it over on itself, back and forth. Quarter, and reject opposite quarters Break finer as may be necessary, and continue to quarter down until a sample is obtained small enough to go into a quart fruit jar, and having no pieces larger than one-fourth inch cube. The sample may, with advantage, be run through a mill which will break it to the size mentioned. Transfer to the jar and make sure the latter is sealed air-tight before it is set aside. All of these operations should be conducted as rapidly as possible to guard against any change in the moisture content of the coal. Modifications of this method will of course suggest themselves, and in some cases will be necessary. When possible, a more representative sample may be secured by taking shovelfuls of the coal at regular intervals during the loading or unloading of the car. In any method of sampling, two conditions must be insisted on; the original sample should be of considerable size and thor- oughly representative, and the quartering down to an amount which can be put in a sealed jar should be carried out as quickly as possible after the sample is taken. In boiler tests shovelfuls of coal should be taken at regular intervals and put in a tight covered barrel, or some air-tight cov- ered receptacle, and the latter should be placed where it is pro- tected from the heat of the furnace. For analysis quarter down further to about 100 grams. Run this portion through a mill which admits of quick grinding with little exposure to the air. A coffee mill set to grind as finely as possible will answer. The grinding of 100 grams is recommended because less moisture will be lost than if a smaller sample is ground. When an accurate determination of moisture is required and especially with coals high in moisture, a portion of this coarsely ground sample must be transferred at once to a tighty stoppered tube for use in determining moisture. Grind 12 or 15 grams of the remainder moderately fine in a porcelain or iron mortar and transfer to a tightly corked tube for use in other de- terminations than moisture. 102 CHEMICAL ANALYSIS FOR GLASSMAKERS. Moisture. — Dry 1 gram of the coal in an open porcelain or plati- num crucible at 104°-107° C. for one hour in a drying oven. Cool in a dessicator and weigh covered. Volatile Combustible Matter. — Place 1 gram of the fresh, undried, powdered coal in a platinum crucible weighing 20 to 30 grams and having a tightly-fitting cover. Heat over the full flame of a Bun- sen burner for 7 minutes. The crucible should be supported on a platinum triangle with the bottom 6 to 8 Cm. (about 3 inches) above the top of the burner. The flame should be fully 20 Cm. (8 inches) high, burning free, and the determination should be made in a place free from draughts. The upper surface of the cover should burn clear, but the under surface should remain covered with carbon. To find the Volatile Combustible Matter, subtract the percentage of moisture from the loss found here. Ash. — Burn the powdered coal used for the determination of Moisture, at first over a very low flame, with the crucible open and inclined, until free from carbon. It is advisable to examine the ash for unburned carbon by moistening it with alcohol. Fixed Carbon. — Subtract the percentage of Ash from the percent- age of coke. Example of a Coal Analysis. Moisture, 1 gram taken: Weight of crucible, cover and coal before drying, 59.6965 Weight after drying, 59.6800 Loss or Moisture, .0165 .0165 X 100 = 1.65 per cent. Moisture. Volatile Combustible Matter, 1 gram taken: Weight of crucible, cover and coal before igniting, 30.5793 Weight after igniting, 30.2187 Loss, .3606 Moisture as found above: .0165 Volatile Combustible Matter, .3441 .3441x100 = 34.41 percent. Vol. Comb. Matter. METHODS OF ANALYSIS. 103 Ash, 1 gram taken: Weight after driving oS Moisture, 59.6800 Weight after burning away Carbon, 59.6057 Ash, .0743 .0743 X 100 = 7.43 per cent. Ash. Fixed Carbon: Weight after igniting, 80.2188 Weight of crucible and cover, 25.5793 Weight of coke, . .6394 Weight of ash, .0743 Weight of fixed Carbon, .5651 .5651 X 100 = 56.51 per cent. Fixed Carbon. Summary of Coal Analysis. Moisture, 1.65 per cent. Volatile Combustible Matter, 34.41 " Fixed Carbon, 56.51 " Ash, 7.43 100.00 Coke. Determination of Moisture, Carbon and Ash: Moisture. — Weigh 1 gram into a vs^eighed platinum crucible, dry- in an air-bath at 104° to 107° C. The loss of weight will be moisture. Carbon. — Place the crucible containing the dried coke over a Bunsen burner in an inclined position and heat until only ash is left. The loss of weight will be Carbon. Ash. — Deduct the weight of the crucible, the result will be ash. Example of Coke Analysis, 1 gram taken: Weight of crucible and cover, 24.2725 Weight of crucible, cover and coke before drying, 25.2725 Weight after drying, 25.2631 Loss, or Moisture, .0094 X 100 = 0.94 per cent. .0094 104 CHEMICAL ANALYSIS FOR GLASSMAKERS. Weight of whole after drying, Weight after burning off the Carbon, Loss, or Carbon, . 9045 X 100 = 90. 45 per cent Weight of whole after burning off Carbon, Weight of crucible and cover, Weight of Ash, .0861 X 100 = 8.61 per cent. Summary. Moisture, .94 Carbon, 90.45 Ash, 8.61 100.00 per cent. GAS ANALYSIS. The Analysis of Gas is a very simple operation and furnishes an efficient means of control for the workings of the gas-producer. By means of analysis we are enabled to ascertain if a producer is being properly managed and the coal is being con- '"^^ verted into the most valuable gases. I f Sampling. — The sample of gas may be taken from the top of the producer. Figure 81 shows the method of sampling. The top of the producer I It ~a. a has a hole h into which is inserted the iron pipe c. The heavy iron plate d, fastened to the pipe, -p.^ gj keeps it upright. A rubber tube e is permanently attached to the upper arm of the pipe. The pipe is placed in the hole, and the gas allowed to escape from the rub- ber tube. After a couple of minutes the gas tube /, filled with water, is attached to e. The stop-cocks h h are opened, and as the water escapes, the gas takes its place in the tube. When the water has all run out, the stop-cocks are closed and the tube removed. The iron pipe is then withdrawn, and the hole b closed with a plug. Fig. 82 shows the gas tube separately. The bore of the ends h k and stop-cocks h h should be as fine as possible, so as to prevent 25.2631 24.3586 .9045 24.3586 24.2725 .0861 METHODS OF ANALYSIS. 105 any air lodging in them and passing into the tube along with the gas. Capillary glass tubing should be used for these parts of the sample tube. The total length of the sample tube should be abou 12 inches, and the diameter of the cylindrical part about 2 inche; outside and about h inch thick. 7^ 1 1 = e Apparatus. — Figure 83 represents an excellent apparatus, de- signed by Dr. Arthur H. Elliott. The tube a is of about 125 Cc. capacity. It has a mark at b, indicating 100 Cc. The tube c is graduated in Cc. and tenths, and has a capacity of 100 Cc. to the 106 CHEMICAL ANALYSIS FOR GLASSMAKERS. mark d. The explosion tube e is also graduated. These tubes are connected with aspirator bottles /, g and h by means of rubl)er tubing. The tube a has a detachable funnel k for the introduction of reagents, and it is fitted with a one-way cock I and a two-way cock TO. The tube c is fitted with a three-way cock n, which per- mits connecting a with either c or e. The ends of the tubes are brought together and joined by pieces of heavy rubber tubing o, o. The whole apparatus may be supported by means of clamps in a similar manner to which a burette is suspended. Reagents. — For the analysis of producer gas, the following are required: Potassium Hydroxide, to absorb Carbon Dioxide : About 50 grams, dissolved in 250 Cc. of distilled water and kept in a bottle with a rubber stopper. Potassium Pyrogallate, to absorb Oxygen. To a solution of Potassium Hydroxide of the above strength, add about 8 grams of Pyrogallic Acid and keep in a similar bottle. Cuprous Chloride, to absorb Carbonic Oxide (CO). A saturated solution in concentrated Hydrochloric Acid and containing a few pieces of clean copper wire. Keep in a glass-stoppered bottle. Oxygen Gas, for the explosion in determining Hydrogen and Marsh Gas, if the percentages of these constituents are required. Oxygen may be purchased in Iron cylinders ready for use. Operation. — First fill the apparatus with water. To do this, place the bottles /, g and h (Fig. 83) on the shelf p, and fill them about two-thirds full of water. Then open the three-way cock n so as to connect e with a. Place the bottle h on the shelf q. The water will rise in e. When it has reached the junction of a, turn n to connect c and a, and place the bottle g on the shelf q. When c is full of water, shut off n entirely. Open m so that / is con- nected with a and place the bottle /on the shelf q. Then open the cock I until the water reaches the funnel k. The apparatus is now ready for the introduction of 100 Cc. of the gas to be tested. Figure 84 shows the manner in which this is performed. The gas tube v is connected* with the aspirator w, by means of a piece of flexible tubing x. The flexible tube y is attached to the other end of V and held in a vertical position, as shown by the dotted lines. The funnel k (Fig. 83) is detached and laid aside. The bottle/ is placed on the lower shelf p and the cock m opened. The METHODS OF ANALYSIS. 107 cocks of V are then opened and a little water permitted to enter v to expel the gas and drive any air out of y. The upper cock of v is closed and the upper end of y pinched with the finger, y is then bent over and connected with the upper end of a. The upper cock of V is again opened. The cock I is then opened and the gas allowed to enter a. When the level of the water in a is a little below the mark h, the cock I is closed. The tube y is detached from a and the bottle / raised until the surface of its contents are on the same level as the water in a. If these levels are at the mark b, the proper volume of gas is contained in a. If above b, more gas must be admitted from y. If below 6, some gas must be expelled by cautiously opening I. The water in a will rise; I is closed when the mark is reached. The funnel k is then replaced on a. Analysis. — Place the bottles / and g (Fig, 83) on the shelf p. Half fill the funnel k with the Potassium Hydrate Solution. Cautiously open I and permit the solution to gradually enter a, allowing it to run down the inner surface. When k is nearly empty, close the stop-cock I and wait a few minutes. Place the .84. 108 CHEMICAL ANALYSIS FOR GLASSMAKERS. bottle /on the shelf q, open the stop-cock n so that a is connected with c, and permit the water to rise in a until it reaches n. Close n and raise g until the surface of its contents are level with the w^ater in c. Observe the number of Cc. and tenths shown on c. This reading will be the percentage of Carbon Dioxide (COg). Turn the cock m so that it delivers through the bottom, open I and permit a to empty through m. When empty, fill k with water and allow it to run through a, washing out the tube. Con- nect a and /by means of m, and allow the water to rise in a until it enters the funnel, then close I. Replace /on the shelf p, and g on the shelf q. Open n and allow the water to rise in c, driving the gas into a. Then close n. Fill k with the Pyrogallate Solu- tion, and allow it to run into a. Place/ on the shelf q, and g on p. Open n, and drive the gas into c. Take the reading as before. The loss of volume will be Oxygen (0). After again washing out a and filling it with water, pass the gas from c, and add Cuprous Chloride Solution by means of k, and then fill k with water and add this also. Pass the gas into c and take the reading. The loss will be Carbonic Oxide (CO). After proceeding thus far, the residue in c may consist of Hy- drogen, Marsh Gas, and Nitrogen. If it is desired to determine these we make use of the explosion tube e. Place the bottle h on the shelf p and g on q. Turn the cock n so that c connects with e, and pass the gas into e. Allow about 20 Cc. of the gas to enter e and close n. Raise the bottle h until the surface of its contents is level with the water in e and take the reading. Connect the stop- cock z by means of a rubber tube with the cylinder of Oxygen Gas, and allow about 75 Cc. of this gas to enter e. Take the reading of e again, and place h as low as possible. Wait a few minutes for the gases to mix. Connect the wires t, t, from the Rhumkorff coil s with the platinum loops u u, and by means of the battery r pass a spark. The mixture in e will explode, and its volume be diminished. Wait a few minutes and then raise the bottle h as before and take the reading. While waiting fill a with water. Place h on the shelf q, and / on p, and open n to pass the gas into a. When in a, fill k with Potash Solution, and allow it to run into a to absorb the Carbon Dioxide (CO2) formed by the ex- plosion. Pass the gas into e and take the reading. Calculate the volumes of Hydrogen and Marsh Gas by the following formulas: METHODS OF ANALYSIS. 109 Let C be the contraction of volume after the explosion. Let D be the CO2 formed by the explosion. Then: 2 C— 4 Hydrogen (H). o D = Marsh Gas (CH4). These calculations will give the volumes of H and CH4 in the 20 Cc. taken for explosion. In order to calculate the H and CH4 in the total volume of gas. multiply the above volumes by the residue left after absorbing the COg, 0, and CO, and divide this result by the volume taken for explosion. After obtaining the percentages of CO 2, 0, CO, H, and CII4 subtract their sum from 100 to get the percentage of Nitrogen (N). Example of Producer Gas Analysis. CO 2 found by absorption with Potash, 4.8 Cc. 0 found by absorption with Pyrogall, ,4 Cc. CO found by absorption with Cuprous Chloride, 18.6 Cc. 23.8 Cc. 100— 23.8 =r 76.2 Cc. residual gas. Taken for explosion, 20.1 Cc. Volume after adding Oxygen, 60. Cc. Volume after explosion, 55.1 Cc. Contraction, 4.9 Cc, Volume after explosion, 55.1 Cc. Volume after absorption with Potash, 54.8 Cc. CO 2 formed by explosion, .3 Cc. Calculation ^ ^ „^ = H in 20. 1 Cc. taken for explosion. 3 D = CH4 in 20.1 Cc. taken for explosion. C =4.9 Cc. Dr= .3 Cc. (2x 0)-(4>^) _ 9.8-1.2 _ ^6 _ 2^ jj .^^ 20. 1 Cc. 3 3 3 Residual Gas '^^•^^^•^ = 10.9 Cc. H in 100 Cc. Gas, 20. X 1^:^^ = 1.1 Cc. CH4 in 100 Cc. Gas. 110 CHEMICAL ANALYSIS FOR GLASSMAKERS. Summary. Carbon Dioxide, CO 2, 4,8 Oxygen, 0, .4 Carbonic Oxide, CO, 18.6 Hydrogen, H, 10.9 Marsh Oas, CH4, 1.1 Nitrogen, N, by difference, 64.2 100 per cent. Conclusions. In producer gas formed by forcing air or steam, or both through burning coal, the valuable constituents are Carbonic Oxide, Hy- drogen, and Marsh Gas; the others are of no value and the pro- ducer should be managed so as to keep their percentages as low as possible. Over 5 per cent, of Carbon Dioxide, and over 0.5 per cent, of Oxygen should be regarded with suspicion as indicating in the former case a producer containing too little coal, and in the latter case the coal loosely packed, or leaks at the grate, allowing the air a too free passage. WATER FOR USE IN STEAM BOILERS. Waters which contain large proportions of the Carbonates and Sulphates of Lime and Magnesia are injurious to boilers, deposit- ing a hard scale, which besides being a poor conductor of heat and thus causing waste of fuel, is the cause of the burning out of the fire tubes. When these salts are present in the water in consider- able quantities, it is called a "Hard Water." In an analysis of boiler water, the following are determined: Hardness, Suspended Matter, Total Solids in solution. Chlorine in Chlorides, Sulphates, Silica, Iron Oxide and Alumina, Lime and Magnesia. Sampling. — Allow the water to run from the hydrant or pump for about 10 minutes. Wash out a gallon bottle with the running water. Fill the bottle, and empty it three times. Then fill it again, and close it tightly Avith a cork. Determination of Hardness. — The solutions required are a Stand- ard Hard Water, and a Standard Soap Solution. Dissolve 1 gram of c. p. Calcium Carbonate in dilute Hydrochloric Acid, and evap- orate to dryness on the water-bath, remove to a sand-bath and heat until all odor of acid has disappeared. Dissolve in a little METHODS OF ANALYSIS. Ill distilled water, wash the solution into a 1-liter graduated flask, fill to the mark with distilled water and mix well by shaking. Pour this solution into a clean, dry bottle and label it as follows: Standard Hard Water 1 Cc. = .001 Gm. CaCOg. Dissolve 10 grams of White Castile Soap in 90 per cent, alcohol, filter into a 1-liter graduated flask, and fill to the mark with more alcohol . Keep in a clean dry bottle, labeled : Strong Soap Solution. To standardize the Soap Solution measure out 10 Cc. of the Standard Hard Water with a pipette, run it into a 6-ounce glass- stoppered bottle and add 90 Cc. distilled water. Drop the Soap Solution into this bottle from a burette, closing the bottle, and shaking it after each addition of the Soap Solution. Continue this until a permanent lather is formed, which will remain unbroken for at least five minutes. This lather must lightly cover the sur- face, and not be thick or frothy. From the number of Cc. and tenths of the Soap Solution used, calculate its value in terms of Carbonate of Lime. Suppose we found it took 19.5 Cc. of the Soap Solution to form the lather, we have: 19.5 Cc. Soap Solution equals 10 Cc. of the Hard Water or .01 gram CaCOg. Therefore 1 Cc. equals .0005128 Gm. CaCOg. Take 100 Cc. of the water to be tested, and run it into a similar glass-stoppered bottle, drop in the Soap Solution exactly as de- scribed above. Multiply the volume used by the value of 1 Cc. The result will be the grams of CaCOg in the 100 Cc. of water. This result multiplied by 10000 will give the degrees of Total Hardness in parts per million. Example: 1 Cc. Soap Solution found equal to .0005128 gram CaCOg. 100 Cc. of Water required 7.5 Cc. Soap Solution to form lather. 7.5 X .0005128 = .003846 gram CaCOg. .003846 X 10000 = 38.46 parts per million of CaCOg. Water may be ''hard" by reason of dissolved Carbon Dioxide, which can be removed by boiling. This is called "Temporary Hardness." To determine this, boil 100 Cc. of the water in a flask for one hour. Keep up the volume by adding from time to time boiled distilled water. Place the flask under a hydrant, and 112 CHEMICAL ANALYSIS FOR GLASSMAKERS. allow cold water to run on the outside. When cool pour into the stoppered bottle and drop in the Soap Solution as above described. The number of grams of CaCOg found will be the Permanent Hardness, this subtracted from the Total Hardness gives the Temporary Hardness. Suspended Matter. — Shake up the sample of water and if much suspended matter is seen, measure out 500 Cc. This is passed through a filter-paper which has been first dried in the oven at about 80° C. and then weighed. When the water has all passed through, wash three times with distilled water, remove again to the oven, and when dry weigh the paper. The increase of weight Avill be Suspended Matter, which multiplied by 2000 gives the parts per million in the water. Total Solids in Solution. — While filtering the water as in the last paragraph, allow the filtrate from the Suspended Matter to run into a weighed platinum or porcelain dish. When the dish is nearly full remove it to a water-bath, and place a large beaker be- neath the funnel. Evaporate the contents of the dish, and from time to time add some of the water from the beaker. When the whole has evaporated to dryness remove the dish to an air-bath and allow it to remain for one hour at a temperature of 130° C. Remove to a desiccator, and weigh when cool. Deduct the weight of the dish. The result will be the Total Solids in Solution. Multiply this by 2000 to get the result in parts per million. Chlorine in Chlorides. — Measure 500 Cc. of the water into a por- celain dish, add a drop of Potassium Chromate Indicator, and from a burette drop in sufficient Standard Silver Nitrate to give the pr(»per red color. (See Salt in Soda Ash, page 55). The number of Cc. and tenths of the Standard Solution used multiplied by .000606 gives the weight of Chlorine, this result multiplied by 2000 gives the Chlorine in parts per million. Example, 500 Cc. of the water taken: Standard Silver Nitrate 5.3 Cc. x .000606 = .0032118 Gm. CI. .0032118 X 2000 = 6.42 parts CI per million. Sulphates. — Measure 500 Cc. of the water into a porcelain dish, add 1 Cc. of dilute Hydrochloric Acid, and evaporate on the water-bath until the volume is reduced to about 200 Cc. Pour into a 250 Cc. beaker, and wash the dish into the beaker with a jet of hot water. Heat the contents of the beaker to boiling and METHODS OF ANALYSIS. 113 add 1 Cc. of hot solution of Barium Chloride. Allow the beaker to st^nd over night and filter. Proceed as described in Sodium Sulphate on page 56. The weight of the Barium Sulphate found, multiplied by 80 and divided by 232 gives the weight of Sulphates (SO3) in the water, and this result multiplied by 2000 gives the parts per million. Example, 500 Cc. of water taken : Weight of crucible, cover and BaS04, 6.9615 Weight of crucible and cover, 6.9535 Weight of BaS04, .0080 .0080 X 5-^2 = -002759. .002759 X 2000 = 5.518 parts SO 3 per milhon. Silica, Alumina and Iron Oxide, Lime and Magnesia. — Measure 1000 Cc. of the water, and filter it into a porcelain dish, add 1 Cc. of concentrated Hydrochloric Acid, and evaporate to dryness on the water-bath. Dissolve the residue in 5 Cc. of dilute Hydro- chloric Acid, and evaporate again to dryness. Redissolve in 5 Cc. dilute Hydrochloric Acid, and add 10 Cc. hot distilled water, filter through a 7 Cm. ashless filter-paper into a 50 Cc. beaker. Wash three times with a jet of hot water, and test the last drops of the filtrate with Silver Nitrate Solution. Ignite the filter in a weighed platinum crucible, cool in a desiccator, weigh and deduct the weight of the crucible, the result will be Silica (SiOj) which multiplied by 1000 gives the Silica in parts per million. Add a drop of concentrated Nitric Acid to the filtrate, boil and add enough strong Ammonia to give a slight odor, boil and filter through a 7 Cm. ashless filter- paper into a 100 Cc. beaker. Wash three times with hot water, or until the last drops of the filtrate- give no reaction with Silver Nitrate Solution. Ignite the filter in a weighed porcelain crucible, cool and weigh. Deduct the weight of the crucible. The result is Alumina and Iron Oxide (AlgOg + FegOa). Multiply this weight by 1000 to get the result in parts per million. To the filtrate from the above add a few drops of strong Am- monia, boil, and while boihng add about 1 Cc. of Ammonium Oxalate Solution. Boil for a few minutes with constant stirring, and set aside for an hour. Filter through a 7 Cm. filter-paper, and wash with hot water until the last drops give no reaction with 8 114 CHEMICAL ANALYSIS FOR GLASSMAKERS. Silver Nitrate Solution. Set the filtrate over a burner and allow it to evaporate. Place a 100 Cc. flask under the funnel and fill the funnel with hot dilute Sulphuric Acid (1 of acid, 5 of water). Fill the funnel three times with hot water. Place the flask under a burette, and titrate with weak Standard Permanganate. The number of Cc. and tenths of the Standard Solution used multiplied by .0005, will give the Lime (CaO), this result multiplied by 1000 gives the parts per million of Lime. When the filtrate from the Calcium Oxalate precipitation has been reduced in volume to about 50 Cc. allow it to cool, add enough strong Amnaonia to give a decided odor, then add 1 Cc, of Sodium Phosphate Solution, stir well for a short time, and allow to stand over night. Filter on a 7 Cm. ashless filter-paper, and proceed as directed on page 71 (Lime Analysis). The weight of the Mg2P207 found, multiplied by 80 and divided by 222, gives the weight of Magnesia (MgO ), and this result multiplied by 1000 gives the parts MgO per million. Example, 1000 Cc. of water taken: Residue insoluble after evaporation with HCl. Weight of crucible and Silica, 7. 1976 Weight of crucible, 7. 1805 Weight of SiOa, .0171 .0171 X 1000 = 17.1 parts SiOj per million. Filtrate from Silica: Weight of crucible and contents, 6.8132 Weight of crucible, 6.8091 Weight of AI2O3 + FcjOg, .0041 .0041 X 1000 = 4.1 parts AlgOg +Fe203 per million. Filtrate from precipitation of Alumina and Iron Hydroxides: Weak Standard Permanganate 12.1 Cc. 12.1 X. 0005 = .00605 CaO. . 00605 X 1000 = 6. 05 parts CaO per million. Filtrate from Calcium Oxalate precipitation: Weight of crucible and contents, 14.8147 Weight of crucible, 14.8040 Weight of MgaPaO^, .0107 .0107x 2^02 = . 00386 MgO. .00386 X 1000 = 3.86 parts MgO per million. METHODS OF ANALYSIS. 115 Calculations. It is customary to report the impurities of water in terms of grains per U. S. gallon of 231 cubic inches. The number of grains in such a gallon has been fixed upon as 58318. The impurities have been determined in parts per million, or in milligrams per liter since 1 milligram is one-millionth of a liter. Therefore to convert into grains per gallon multiply by 58318 and divide by one million. Taking the results found above we have: Parts Grains per Million. per Gallon. Total Hardness, 38.46 X 5 8 31 8 i w 1.0000 1.0069 1.0140 1.0211 1.0284 1.0357 1.0432 1.0507 1.0584 1.0662 1.0741 1.0821 1.0902 1.0985 1069 1154 1240 1328 1417 1508 1600 1694 1789 1.1885 1.1983 1.2083 1.2185 1.2288 1.2393 1.2500 1.2609 1.2719 1.2832 1.2946 1.3063 1.3182 1.3303 1.3426 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 Cl, O 1.3551 1.3679 1.3810 1.3942 1.4078 1.4216 1.4356 1.4500 1.4646 1.4796 1.4948 1 5104 1.5263 1.5426 1.5591 1.5761 1.5934 1.6111 L6292 1.6477 1.6667 1.6860 1.7059 1.7262 1.7470 1.7683 1.7901 1.8125 1.8354 1.8590 1.8831 1.9079 1.9333 1.9595 1.9863 2.0139 2.0423 2.0714 For Liquids Lighter than Water. Temp. 15° C. 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 1.0000 .9929 .9859 .9790 .9722 .9655 .9589 .9524 .9459 .9396 .9333 .9272 .9211 .9150 .9091 .9032 .8974 .8917 .8861 .8805 .8750 .8696 .8642 .8589 .8537 .8485 .8433 .8383 .8333 .8285 .8234 .8187 .8139 .8092 .8046 .8000 .7955 .7909 48 .7865 49 .7821 50 .7777 51 .7735 52 .7692 53 .7650 54 .7609 55 .7568 56 .7527 57 .7487 58 .7447 59 .7407 60 .7368 61 .7329 62 .7292 63 .7254 64 .7217 65 .7179 66 .7143 67 .7107 68 .7071 69 .7035 70 .7000 71 .6965 72 .6931 73 .6897 74 .6863 75 .6829 76 .6796 77 .6763 78 .6730 79 .6698 80 .6666 TABLES. 123 PEKCENTAGE AND GKAVITY OF SULPHURIC ACID. Table showing percentages of Actual Sulphuric Acid (H2SO4) corresponding to varions Specific Gravities of Aqueous Sulphuric Acid ( Bineau ) ; Otto. Temp. 15°C. Specific Gravit CenI !inc ravif CenI ;iiic ravil CenI SO CenI P-i Ck a5 CD Per Sh 4) CO &< CO 0-i 1.8426 100 1.675 75 1.398 50 1.182 25 1.842 99 1.663 74 1.3886 49 1.174 24 1.8406 98 1.651 73 1.379 48 1.167 23 1.840 97 1.639 72 1.370 47 1.159 22 1.8S84 96 1.627 71 1.361 46 1.1516 21 1.8376 95 1.615 70 1.351 45 1.144 20 1.8356 94 1.604 69 1.342 44 1.136 19 1.834 93 1.592 68 1.333 43 1.129 18 1.831 92 1.580 67 1.324 42 1.121 17 1.827 91 1.568 66 1.315 41 1.1136 16 1.822 90 1.557 65 1.306 40 1.106 15 1.816 89 1.545 64 1.2976 39 1.098 14 1.809 88 1.584 68 1.289 88 1.091 13 1.802 87 1.523 62 1.281 37 1.088 12 1.794 86 1.512 61 1.272 86 1.0756 11 1.786 85 1.501 60 1.264 85 1.068 10 1.777 84 1.490 59 1.256 84 1.061 9 1.767 83 1.480 58 1.2476 33 1.0536 8 1.756 82 1.469 57 1.239 82 1.0464 7 1.745 81 1.4586 56 1.231 81 1.039 6 1.734 80 1.448 55 1.223 30 1.032 5 1.722 79 1.438 54 1.215 29 1.0256 4 1.710 78 1.428 58 1.2066 28 1.019 S 1.698 77 1.418 52 1.198 27 1.013 2 1.686 76 1.408 51 1,190 26 1,0064 1 124 CHEMICAL ANALYSIS FOR GLASSMAKERS. PERCENTAGES AND GEAVITY OF HYDEOCHLORIC ACID. Table showing the percentages of Hydrochloric Acid in Aqueous Solutions of the Gas of Various Specific Gravities. Ure; Temp. 15° C. Specific Gravity. HCl Per Cent. Specific Gravity. HCl Per Cent. Specific Gravity. HCl Per Cent. Specific Gravity. HCl Per Cent. 1.200 40.777 1.1515 30.582 1.1000 20.388 1.0497 10.194 1.1982 40.369 1.1494 30.174 1.0980 19.980 1.0477 9.786 1.1964 39.961 1.1473 29.767 1.0960 19.572 1.0457 9.379 1.1946 39.554 1.1452 29.359 1.0939 19.165 1.0437 8.971 1.1928 39.146 1.1431 28.951 1.0919 18.757 1.0417 8.563 1.1910 38.738 1.141 28.544 1.0899 18.349 1.0397 8.155 1.1893 38.330 1.1389 28.136 1.0879 17.941 1.0377 7.747 1.1875 37.923 1.1369 27.728 1.0859 17.534 1.0357 7.340 1.1857 37.516 1.1349 27.341 1.0838 17.126 1.0337 6.932 1.1846 37.108 1.1328 26.913 1.0818 16.718 1.0318 6.524 1.1822 36.700 1.1308 26.505 1.0798 16.310 1.0298 6.116 1.1802 36.292 1.1287 26.098 1.0778 15.902 1.0279 5.709 1.1782 35.884 1.1267 25.690 1.0758 15.494 1.0259 5.301 1.1762 35.476 1.1247 25.282 1.0738 15.087 1.0239 4.893 1.1741 35.068 1.1226 24.874 1.0718 14.679 1.0220 4.486 1.1721 34 660 1.1206 24.466 1.0697 14.271 1.0200 4.078 1.1701 34.252 1.1185 24.058 1.0677 13.863 1.0180 3.670 1.1681 33.845 1.1164 23.650 1.0657 13.456 1.0160 3.262 1.1661 33.438 1.1143 23.242 1.0637 13.049 1.0140 2.854 1.1641 33.029 1.1123 22.834 1.0617 12.641 1.0120 2.447 1.1620 32.621 1.1102 22.426 1.0597 12.233 1.0100 2.039 1.1599 32.213 1.1082 22.019 1.0577 11.825 1.0080 1.631 1.1578 31.805 1.1061 21.611 1.0557 11.418 1.0060 1.124 1.1557 31.398 1.1041 21.203 1,0537 11.010 1.0040 .816 1.1536 30.990 1.1020 20.796 1,0517 10.602 1.0020 .408 TABLES. 125 PERCENTAGES AND GEAVITY OF NITEIC ACID. Table showing the percentages of Nitric Acid (HNO3) in Aqueous Solutions of Various Specific Gravities. Kolb, Ann. Ch. Phys. (4), 136. Temp. 15° C. a v 0 W Specific Gravity. fi 0 53 Specific Gravity. OS W Specific Gravity. c Specific Gravity. lUU.UU 1.530 an Oft 1.463 59 59 1.372 39.00 1.244 QQ Szl yy.o4: 1.530 8n AA oU. uu 1.460 58.88 1.368 37.95 1.237 QQ 79 yy. / z 1.530 7Q AA 1.456 58.00 1.363 36.00 1.225 99.52 1.529 77.60 1.451 57! 00 1.358 35! 00 1.218 97.89 1.523 76.00 1.445 56.10 1.353 33.86 1.211 97.00 1.520 75.00 1.442 55.00 1.346 32.00 1.198 96.00 1.516 74.01 1.438 54.00 1.341 31.00 1.192 95.27 1.514 73.00 1.435 53.81 1.339 30.00 1.185 94.00 1.509 72.39 1.432 53.00 1.335 29.00 1.179 93.01 1.506 71.24 1.429 52.33 1.331 28.00 1.172 92.00 1.503 69.96 1.423 50.99 1.323 27.00 1.166 91.00 1.499 69.20 1.419 49.97 1.317 25.71 1.157 90.00 1.495 68.00 1.414 49.00 1.312 23.00 1.138 89.56 1.494 67.00 1.410 48.00 1.304 20.00 1.120 88.00 1.488 66.00 1.405 47.18 1.298 17.47 1.105 87.45 1.486 65.07 1.400 46.64 1.295 15.00 1.089 86.17 1.482 64.00 1.395 45.00 1.284 13.00 1.077 85.00 1.478 63.59 1.393 43.53 1.274 11.41 1.067 84.00 1.474 62.00 1.386 42.00 1.264 7.22 1.045 83.00 1.470 61.21 1.381 41.00 1.257 4.00 1.022 82.00 1.467 60.00 1.374 40.00 1.251 2.00 1.010 COMPARISON OF WEIGHTS AND MEASURES, U. S. PHARMACOPOEIA. Measures of Length. 1 Meter = 39.370432 inches. 1 Decimeter = 3.937043 " 1 Centimeter 0.393704 " 1 Millimeter = 0.039370 " 1 Yard (or 36 inches) = 0.91439 Meter. 1 Foot (or 12 inches) — 30.48 Centimeters. Inches. Centimeters. Inches. Centimeters. Inches. Millimeters. 11 = 27.9 5 = 12.7 it = 12.5 10 = 25.4 4 =^ 10.2. i = 6.25 9 = 22.9 3 = 7.6 i = 3.12 8 = 20.3 2 = 5.1 1 = 1.54 7 =-= 17.8 1 = 2.5 1 55 = 1.00 6 = 15.2 126 CHEMICAL ANALYSIS FOR GLASSMAKERS. Measures of Capacity. Cubic Fluid Cubic Fluid Cubic Centimeters. Ounces. Centimeters. Drachms. Centimeters. Minims. 1000 = 33.81 25 = 6.76 3 48.69 900 = 30. 43 20 = 5.41 2 32.46 OUU - — 07 AC; 15 == 4.06 1 1 A OO ZO. 0 / 10 = 2.71 0.75 1 O 1 7 AHA OA OQ 9 = 2.43 0.50 0.1 ii ouu 1 A OA — io.yu 8 = 2.16 0.25 A nit 4.Ud W\J — 16. Oo 7 = 1.89 0.20 *J OJ^ 1 A 1 1 6 = 1.62 0'.15 200 = 6.76 5 = 1.35 0.10 — 1.62 100 = 3.38 4 = 1.08 0.05 — 0.81 50 = 1.69 , 10 = .34 1 = .03 Cuhic Cuiyic _ , . J^tTliTftSt CeTttivfieters. • Jainims. CentiTneters. Minims. 1 A AA 8 — 0.49 35 — 15. lb A 1 O = u.oo 4U Q A 1 Q 10 = 0.62 45 Z. i I 4 = 0.25 15 = 0.92 50 O. Uo 5 = 031 20 = 1.23 55 3.39 6 = 0.37 25 = 1.54 60 3.70 7 = 0.43 30 = 1.85 Fluid Cubic Fluid Cubic Fluid Cubic Drachms. Centimeters. Ounces. Centimeters. Ounces. Centimeters. 1 = 3.70 1 = 29.57 9 266.10 2 7.39 2 = 59.10 10 295.68 3 = 11.09 3 = 88.67 12 354.82 4 14.79 4 = 118.24 16 473 11 5 -= 18.48 5 = 147.81 24 709.80 6 = 22.18 6 = 177.39 32 946.38 7 = 25.88 7 = 206.96 64 1892.75 8 = 29.57 8 = 236.53 128 3785.51 Measures or Weight. Grams. Troy Orains. Cframs. Troy Grains. Grams Troy Grains. Grams. Troy Orains. 0.0010 0.015 0.0100 0.154 0.10 1.543 1 15.432 0.0013 0.019 0.0125 0.193 0.12 1.852 2 30.865 0.0015 0.023 0.0150 0.231 0.15 2.315 3 46.297 0.0020 0.031 0.0200 0.309 0.20 3.086 4 61.729 0.0025 0.039 0.0250 0.386 0.25 3.858 5 77.162 0.0030 0.046 0.0300 0.463 0.30 4.630 6 92.594 0.0035 0.054 0.0350 0.540 0.35 5.401 7 108.026 0.0040 0.062 0.0400 0.617 0.40 6.173 8 123.459 0.0045 0.069 0.0450 0.694 0.50 7.716 9 138.891 0.0050 0.077 0.0500 0.772 0.60 9.259 10 154.323 0.0055 0.085 0.0550 0.849 0.70 10.803 20 308.647 0.0060 0.093 0.0600 0.926 0.80 12.346 30 462.970 0.0065 0.100 0.0650 1.003 0.90 13.899 40 617.294 0.0070 0.108 0.0700 1.080 50 771.617 0.0075 0.116 0.0750 1.157 100 1543.235 0.0080 0.123 0.0800 1.235 200 3086.470 0.0085 0.131 0.0850 1.312 500 7716.174 0.0090 0.139 0.0900 1.389 750 11574.262 0.0095 0.147 0.0950 1.466 1000 15432.350 TABLES. 127 Troy Grains. Grams. Troy Grains. Grams. = 0.00101 i = 0.00810 = 0.00108 ^ = 0.01296 s\ - 0.00130 } = 0.01620 i-Q = 0.00162 J = 0.03240 = 0.00202 I = 0.04860 is = 0.00216 1 = 0.06480 ■i^ = 0.00270 2 = 0.12960 2V = 0.00324 3 = 0.19440 tV ^ 0.00405 4 = 0.25920 t\ = 0.00540 5 = 0.32399 j\ = 0.00648 6 = 0.38879 Ounces. Grams. 1 = 31.103 2 = 62.207 3 = 93.310 4 = 124.414 5 = 155.517 Avoirdupois. Grams. Ounces. Grains. 28.35 1 29 1 10 30 1 25i 35 1 103 40 1 180 50 1 334 60 2 50J 70 2 205 80 2 359 90 3 76J 100 3 230* Troy Grains. Grams. Drachms. Grams. 7 = 0.45359 1 = 3.888 8 = 0.51839 2 = 7.776 9 = 0.58319 3 = 11.664 10 = 0.64799 4 = 15.552 20 := 1.296 0 = 19.440 30 = 1.944 6 = 23.328 40 = 2.592 7 27.216 50 == 3.240 Ounces. Grams. 6 = 186.621 7 = 217.724 8 = 248.823 9 = 279.931 10 = 311.035 Avoirdupois. Grams. Ounces. Grains. 200 7 24 250 8 368 300 10 255 350 12 151i 400 14 48 450 15 382 600 17 279 600 21 72 700 24 303 800 28 96 900 31 326^ 1000 35 120 Avoirdupois. Avoirdupois. Ounces. Grams. Ounces. 1.772 7 3.544 8 7.088 9 14.176 10 1 28.350 11 2 56.699 12 3 85.049 13 4 113.398 14 5 141.748 15 6 170.098 16 Avoirdupois. Grams. Pounds. Grams. 198.447 1 453.592 226.796 2 907.18 255.146 3 1360.78 283.496 4 1814.37 311.846 6 2267.96 340.195 6 2721.55 368.544 7 3175.14 396.894 8 3628.74 425.243 9 40S2.33 453.592 10 4535.92 NOTES UPON THE USE AND CARE OF PLATINUM WARE. By Baker & Co., Mfrs. of Hammered Platinum Ware, Newark, N. J. It is important to remember that, although platinum is not oxidized in the air at any temperature, nor attacked by any single acid, yet there are many substances that attack and combine with it at comparatively low temperatures. The caustic alkalies, the alkaline earths, nitrates and cyanides, and especially the hydrates of barium and lithium, attack platinum at a red heat, although the alkaline carbonates have no effect at the highest temperatures. Sulphur, in the absence of alkalies, has no action, but phosphorous and arsenic attack platinum when heated with it. Direct contact of platinum with burning charcoal should be avoided, since the silicon reduced from the charcoal ash unites with platinum, making it brittle and liable to fracture. Also contact with compounds of the easily reducible metals is especially dangerous at high temperatures, as alloys with platinum having a low fusing point are readily formed. This is especially true of lead. Heating of platinum with spirit lamps is preferable to the use of ordinary gas. When gas is used, care should be taken to have the supply of air sufficient to insure coniplete combustion, since, with a flame containing free carbon, the platinum suffers deterior- ation by the formation of a carbide of platinum, which, oxidizing later, blisters the metal. For this reason, also, the inner cone or reducing flame should not be in contact with the metal. The loosening effect of the Bunsen flame upon the surface of platinum exposed to its action produces the familiar gray appear- ance which cannot be removed except by burnishing. Platinum triangles often become gray and very brittle from the same cause. Systematic application of moist sand to all articles affected in this way, after use, will keep them in prime condition and materially prolong their life, with but a trifling loss in weight. ( 128 ) USE AND CARE OF PLATINUM WARE. 129 CLEANING PLATINUM WARE. Every careful analyst of necessity uses clean utensils. A habit of cleaning and polishing platinum dishes immediately after using is easily formed, and repays the user with increased confidence in his work as well as in the prolonged life of the article. Rubbing the surface of platinum with moist sea sand (round grains only), applied Avith the finger, serves to remove most im- purities and to polish the metal without material loss. Fusing bisulphate of potash or borax in the dish and then boil- ing in water and polishing as above with sand is recommended by Gmelin. When it is desired to clean the outer surface of dishes in this manner, they must be placed in dishes of sufficient size to allow the fused flux to completely envelope the article to be cleaned. Sodium amalgam possesses the property of wetting platinum Avithout amalgamating with it, even when other metals are pur- posely added to the amalgam. This substance is, therefore, use- ful for effecting a quick and thorough cleansing of platinum. The amalgam is gently rubbed upon the metal with a cloth and then moistened with water, which oxidizes the sodium and leaves the mercury free to alloy Avith foreign metals. The mercury is then wiped off and the dish cleaned and polished with sand, as above described. If the existence of a base metal alloyed with the platinum is suspected, immerse the article in question first in boiling HCl for a few minutes, then, after thorough rinsing with clean water, immerse in boiling HNO3 acid free from chlorine. If the dish is unaffected in weight or appearance, and the acid baths fail to give reactions for the base metals, their absence in appreciable quantities is assured. 9 INDEX. A PAGE Acid, Acetic, reagent " Hydrochloric, reagent 43 " " standard 35 " " tables 124 " Hydrofluoric, reagent 43 " Nitro-hydrochloric, reagent 43 " Nitric, reagent 42 " " tables 125 " Sulphuric, reagent 42 " " tables 123 Ammonium Carbonate, reagent 47 " Chloride, reagent 47 " Hydroxide, reagent 46 " Oxalate, reagent 47 " Sulphide, reagent 46 Analysis, General Procedure ^ " Methods of 53 " Volumetric 30 Aqua Kegia, reagent 43 Arsenic analysis Atom, the 1 Atomic weights, tables 120 B Balance, analytical ^ " for reagents 40 Barium Carbonate analysis ^"^ " Chloride, reagent 49 Baryta Glass analysis Batch analysis Baths, air 28 " sand 27 " water 27 Beaker 12 Bellows 26 ( 131 ) 132 INDEX. PAGE Blast Lamp 13 26 Bottles, dropping 35 " reagent 52 Bromine, reagent 43 Bunsen Burner 13 25 Burettes 3] Burette clamp 33 c Calcium Carbonate, reagent 49 " Chloride, reagent 49 " Fluoride analysis 79 Carbon Dioxide, reagent 43 Casseroles 27 Centigram, the 4 Centimeter, the 3 Centiliter, the 3 Chemical Theory 1 Clay Analysis 8(5 Coal Analysis 100 Cobalt in Manganese ore 75 " in Sand 90 Coke Analysis 103 Compound, the 1 Cone, platinum 19 Crucibles, Gooch 20 " platinum 13, 25 " porcelain 25 Crucible tongs 25 Cryolite Analysis '. 79 Cubic Centimeter, the 3 Cupric Sulphate, reagent 50 Cylinder, measuring . 40 " for Hydrometer 118 D Decigram, the 4 Deciliter, the 3 Decimeter, the 3 Density of bodies 11(5 Dessicator 23, 25 Dishes, platinum 27 " porcelain 27 Drying precipitates 22 INDEX. 133 PAGE E Element, the .... 1 Erlenmeyer flask 35 Evaporation 27 Exhausting apparatus 21 F Feldspar analysis 88 Ferrous Sulphate, reagent 50 Filtering 14, 19, 20 Filter paper 14, 21 " stand IG Fire brick analysis 88 Flask . . . 12 " Erlenmeyer 35 " Volumetric 30 Float for burette 32 Fluorides analysis ..... 78 Fluorspar analysis 79 Fuel analysis 100 Fume closet 29 Funnel 15 G Gas Analysis 104 "bag 45 " generators 44 Gases, reagents 43 Glass Analysis 91 " " calculations 97 " containing Barium 95 " " Lead 93 " " Zinc 96 " vial 11 Gram, the 3 H Hydrogen 45 " di Sodium Phosphate, reagent 47 " Sulphide, reagent 44 Hydrometer 118 " tables 122 134 INDEX. PAGE I Igniting 21 Indicators: Methyl Orange 35 Potassium Chromate 38 Uranium Acetate 39 Insoluble Substances 13 Iron Wire 50 K Kilogram, the 4 L Lead Glass analysis 93 Lime analysis 70 Litmus paper 51 Liter, the 3 M Magnesia Mixture, reagent 49 Manganese analysis 74 " Cobalt in 75 Measures, comparative tables 125, 126 Meniscus, the 32 Meter, the 3 Methyl Orange Indicator 35 Metric System, the 3 Microcosmic Salt, reagent 47 Milligram, the '. • 4 Millimeter, the 3 • Milliter, the 3 Mixing Jar 36 Molecule, the 1 Mortars and Pestles . 6 o Oven for drying 22 Oxygen 45 P Partially soluble substances 13 Pinchcock 31 Pipettes 33 Platinic Chloride, reagent 50 Platinum ware, cleaning of 129 " " use and care of 128 Policeman 17 INDEX. 135 PAGE Potash analysis 69 Potassium Bichromate, reagent 48 " Bisulphate, reagent 48 " Carbonate, reagent 46 " Chromate Indicator 38 " Ferri cyanide, reagent 48 " Ferrocyanide, reagent 48 " " standard 89 " Hydroxide, reagent 46 " Nitrate analysis 70 " " reagent 47 " Permanganate, reagent 48 " " standard 36, 37 " Thiocyanate, reagent 48 Precipitation 13 Precipitates, different kinds . ■ 14 Q Quanti valence 2 R Reaction 14 Eeagents 40 Eing Stand 13 S Sampling 5 Sampling tool 5 Sand analysis 89 " simple tests 90 Salt Cake analysis 60 " reagent 40 " standard solution 38 Silicate analysis 81 " Flux 46 Silver Nitrate, reagent 51 " " standard 37 Soda Ash analysis 53 " " " notes 58 " Lime, reagent 49 Sodium Ammonium Phoshate, reagent 47 " Bicarbonate analysis 62 " " calculation 65, 68 " Bisulphate, reagent 48 " Carbonate, reagent 46 " " standard 34 136 INDEX. PAGE Sodium Chloride, reagent 38 " Hydroxide, reagent 46 " Nitrate analysis 61 " " reagent 47 " Phosphate, reagent 47 Soluble Substances 12 Solution 12 Spatula . 11 Specific Gravity 116 " " bottles 117 Standard Solutions 34 Stills 41 T Tables, Atomic Weights 120 " Hydrochloric Acid 124 " Hydrometers 122 Metric 4, 125 to 127 " Nitric Acid 125 " Sulphuric Acid 123 " Thermometer 121 " Weights and Measures 125 to 127 Titration 32 Triangles 25 Tripod 12 Turmeric paper 51 u Uranium Acetate, reagent 39 V Valence 2 w Wash Bottles, use of 15 to 18 Watch Glasses 8 Water for Boilers, analysis of 110 " distilled 40 Weighing • • 7, 10 Weights, analytical 9 '• for reagents 40 z Zinc Glass 96 Oxide analysis 77 '■ reagent 51 " standard solution 38