162 Magnetisation of Ilmenite (Titanic Ironstone). on the assumed ground of greater purity, while, on testing the two, I found the French preparation to be, in reality, not basic nitrate at all, but oxychloride, the American being what it professed to be. Mr. Nelson undertook to determine the proportion of bismuth present in some specimens of material from the two sources named. The following are his results, two of the determinations being by another hand : may be considered as essentially due to water retained. On the other hand, the much greater deficiency of chlorine as compared with the requirement of the formula is, doubtless, caused by the practice of saving bismuth by the addition of alkali to the water used for precipitation, leading to the presence of hydrate. The use of water of ammonia for this purpose is prescribed by the present United States pharmacopoeia, and to this is partly due the fact that in the American preparations we find the percentage of bismuth intermediate between that of the normal basic nitrate There is some little confusion observable in the published statements as to the occurrence of ammonium oxalate in Peruvian guano. The older analyses generally represent it as present. In the first Appendix to Dana's "Mineralogy" (1872), oxammite is mentioned amongst "other names given by Shepard for supposed new species consisting of oxalate of ammonia, In the second Supplement to Watts's "Dictionary of Chemistry it is stated that, "according to Chevreul, the crystallisable material dissolved from guano by cold water consists mainly of ammonium oxalate mixed with yellow, red, and brown organic colouring matters." On the other hand, several of the older analyses do not mention the compound at all, or substitute calcium oxalate for it. And in the Journal of the Chemical Society for January, 1875, p. 100, among the salts found by E. Chevreul in his late minute examination of guano are quoted calcium oxalate and ammonio-potassic oxalate, but not the simple ammonium salt. A manufacturing firm placed in my hands a year or two a lump of material of crystalline appearance, weighing something more than a pound, taken from a bag of Guanapi guano, which qualitative examination showed to consist of nearly pure ammonium oxalate without other bases. In order fully to settle the question of its identity, and of the occurrence of this salt ready formed in guano, Dr. Tanner made a quantitative analysis of picked crystals, which were, however, so small (generally 1 or 2 millimetres long) that it was impossible mechanically to get rid of the whole of the brown organic matter encrusting and lying between the colourless crystals themselves. This impurity also interfered with determination of crystalline form. The ammonia was obtained by Schlösing's method CHEMICAL NEWS, Oct. 1, 1875. expulsion by solution of sodium hydrate at ordinary temperature under a bell-glass, and reception in a known amount of standard sulphuric acid. Oxalic acid was precipitated by calcium acetate, and the calcium carbonate left on properly heating the precipitate weighed. Organic matter was left undissolved by the use of a small quantity of water. Analysis gave Deducting the organic matter, we have The ordinary crystallised salt, Ca(NH4)204.H2O, requires (NH4)2 C204 H2O while the normal salt, with two molecules of water of crystallisation, C2(NH4)2O4.2H2O, requires University of Virginia, August 20, 1875. MAGNETISATION OF ILMENITE (TITANIC IRONSTONE). Its sp. gr. was 48, and it acted with tolerable energy upon the magnetic needle. From the inspection of this action I concluded that it was possessed of a very considerable number of poles in close proximity to each other, so that scarcely two closely adjacent parts acted in the same manner upon the north pole of the needle; hence it was evidently built up by a mass of crystals. An elongated rectangular piece of this mineral was separated by a blow of the hammer; it measured 1 ins. in length and was about in. broad. This was placed upon a table and submitted to magnetisation by friction with good magnets for upwards of an hour. It was then found to have a pole at each extremity, which it certainly had not before, and was accordingly suspended to a piece of silk, and hung up in a quiet corner of the laboratory. It pointed constantly towards the north, and returned to that position when deviated. It continued to do so for some weeks; but one morning I found it pointing east-west, or nearly so; it had lost its acquired magnetism entirely, having retained NEWS it for rather more than a month. This loss occurred rather suddenly, and I am of opinion that it coincided with a magnetic storm of some intensity which happened about the time. If these experiments could be continued by some who have more time to devote to them, they might lead to some interesting results. It is possible that some minerals that show no action upon the needle might be made magnetic in the above manner. THE ESTIMATION OF NITRITES IN WATER. THERE are two reactions, by the aid of which liberated nitrous acid may be estimated : taining o'or centigrm. of nitrous acid in each c.c. A solution of iodine (about 4 grammes per litre) in potassium iodide is also prepared, and adjusted of such strength that 10 c.c. made up to 200 c.c. with pure water shall produce the same colour as 10 c.c. of the standard nitrite solution made up to 200 c.c. with water containing potassium iodide and some dilute sulphuric acid. The iodine reaction being developed in a certain quantity of water containing nitrites (as in the preceding process) an equal colour is produced in an equal quantity of pure water by the addition of the standard iodine solution; each c.c.=o'of centigrm. of nitrous acid. 3. A Simpler Colorimetric Process.-Mr. Holland's process adds two standard solutions to those used in water analysis, besides giving the trouble of obtaining a pure nitrite. I dispense with these additions by the following 1. The reducing action on potassium permangate, simple process. It is founded on the liberation of iodine 2. The reaction with potassium iodide. by a permanganate* under the same circumstances as its The second reaction is by far the more sensitive; while liberation by nitrous acid; o'or centigrm. of active oxygen o'028 centigrm. of nitrous acid in a litre of water only contained in I c.c. of the dilute standard solution of perrequires o'or centigrm. of oxygen, yielded by I c.c. of the manganate commonly used (0'395 gramme per litre) dilute standard permaganate solution, it liberates from liberates o'16 (more correctly o'159) centigrm. of iodine; potassium iodide 1'19 centigrm. of iodide, a quantity suffi- while o‘or centigrm. of nitrous acid liberates o'40 centigrm. cient for accurate estimation either volumetrically or of iodine under the same circumstances. The application colorimetrically. Besides the failure of the permanganate of this principle to colorimetric estimation is obvious; reaction (Péan de St. Gilles's process) in the case of o'or centigrm. of active oxygen contained in I c.c. of the minute quantities perfectly estimable by the iodine reaction, dilute standard permanganate solution will, in a comparathe former is masked or simulated by the action of organic | tive experiment, liberate the same quantity of iodine as matter. Dr. Paul recommends to use the permanganate 0'004 centigrm. of nitrous acid. Let the iodine reaction be after ridding the water of organic matter by alum precipi- produced, as in the first process, in 500 c.c. of the water tation and boiling; but I find this treatment will fre- under examination. When the colour is fully developed quently leave, if not all the organic matter, at least suffi- add in the same way potassium iodide and sulphuric acid cient to simulate much nitrous acid when none is present. to 500 c.c. of pure water, and then drop in the dilute Dr. de Chaumont proposes (Parkes's "Hygeine") a converse standard permanganate solution until an equal iodine device, viz., to expel the nitrous acid by boiling the colour is produced. The development of the colour is water after acidifying, and to take the difference between immediate. the quantity of permanganate now required, and that used without the boiling as indicating the amount reduced by nitrous acid; but it is evident, amongst other objections, that in few cases with the reaction with organic matter (already unsatisfactory in itself), either admit of such refinements or be clear enough for any value to be attached to the difference which may occur between the two experiments. But except in the case where sulphuretted hydrogen is present in water (and even then it can be removed) the well-marked and very sensitive reaction of nitrous acid on potassium iodide is always applicable. There are three processes available: 1. Volumetric Estimation by Arsenious Acid.-This is an application of a well-known class of determinations; 198 of arsenious acid will absorb 508 of iodine, which amount is liberated by 12.2 of nitrous acid (12.5 is probably the more accurate figure, the proportion being as nearly as possible 40 to 1); it may be taken that each c.c. of a centinormal solution of arsenious acid (1.98 gramme per litre) will absorb the iodine liberated by o'0125 centigrm. of nitrous acid. I use the process in the following manner :-To 500 c.c. of the water, in a stoppered white bottle, add 5 c.c. of potassium iodide solution (one-tenth) and then 5 c.c. of dilute (one-tenth) pure sulphuric acid. Allow the reaction an hour for full development. If the iodine be liberated in very small quantity, or if it be masked by turbidity of the water, add a drachm of benzine or chloroform and agitate; the iodine will give it a pink colour which is quite as sensitive as the blue colour given by starch, and disappears more quickly when the iodine is absorbed. Under ordinary circumstances I use neither benzine nor starch, the yellow colour of the free iodine is sufficient. In order to estimate the iodine, neutralise the acid by a slight excess of sodium carbonate (caustic alkalies often contain nitrites), and drop in the centinormal arsenious solution until the iodine colour dis The first process is well adapted for laboratory work, especially as the arsenious solution is useful for other purposes besides water analysis. The third process is hardly less accurate; I devised it for use while travelling in India, in order to reduce the number of standard solutions carried about. Carlisle Castle, Sept. 23, 1875. ON THE PURIFICATION OF CARBON By SERGIUS KERN, St. Petersburg. ORDINARY carbon disulphide (CS2) has a very disagreeable odour, owing to the presence of some hydrogen compounds which are formed during the preparation of the product Beside this the compound often contains free dihydric by the action of nascent hydrogen on the carbon disulphide. sulphide (H2S). In order to set the carbon disulphide free from the impurities it is well shaken up with mercury; but this modus operandi is a tiresome one and the product is not well cleaned. The following method was found to be the best for cleaning impure carbon disulphide :-The impure product is well mixed in a high glass with some lead nitrate (Pb2NO3) and with a small quantity of metallic lead; when the salt turns dark, the liquid is poured into another glass with a fresh quantity of the lead salt, and so on until the salt remains nearly white while mixed with the liquor. The carbon disulphide is then placed in a retort, and distilled over into a well cooled receiver. During these experiments a peculiar phenomenon was observed; when the salt was mixed in the crystalline form with carbon disulphide during 10-15 minutes, the crystals were covered with a silver-like precipitate. If these crystals placed on filtering paper are examined *This reaction has, I need hardly say, nothing to do with the action of permanganate on nitrous acid. 164 Manufacture of White Caustic Soda. through a microscope they have a very beautiful appear-, and chromatropes. In the American civil war it was used ance. These experiments are not finished, and if the in sieges to light up forts. The English war department results prove of interest they will be communicated. has tried it in barracks, in large halls and courts, in which it is said to have proved cheaper than coal-gas, whilst the smallest characters could be read at a distance of go metres from the source of light. DEVELOPMENT REPORT OF THE CHEMICAL ARTS (To be continued.) ON THE MANUFACTURE OF WHITE By GEORGE E. DAVIS, F.C.S. ALTHOUGH the manufacture of soda-ash is spread throughout the whole length and breadth of Lancashire, the manufacture of the hydrate commonly called caustic soda is concentrated in Widnes and St. Helens. Books give us but little information upon the subject of white caustic soda, cream caustic is mentioned in a few; but even that was written upon when the manufacture was in its infancy; and though but little change has been made in this branch of late, still the chemistry of the process has received much development. Before describing the process of manufacture in its THE temperature of the flame does not, however, depend exclusively on the heat of combustion. The density of the burning body and the specific heat of the products of combustion must also be taken into account. Hence it comes that the temperature of the hydrogen flame in pure oxygen is about 6800°, in air about 2600°; the temperature of the flame of carbonic oxide in oxygen amounts to 7000°, in air about 3000°; † further according to calculation I vol. of hydrogen = 1 grm. is capable of fusing 205 grms. of platinum, whilst the same volume of carbonic oxide can fuse 238 grms. of platinum (melting-point 2000°.) In practice, however, even under the most favourable condiditions, as Deville and Debray determined in their re-chemical and physical details, I would wish to lay before searches on platinum, about half the heat is lost by conduction to the furnace and other surrounding matter, and the above authorities with 120 litres of hydrogen and 60 of oxygen succeeded in fusing only 1 kilo. of platinum instead of double the amount as calculated. Platinum can also be smelted and refined under similar circumstances with coal-gas. But for the more infusible metals of the platinum group, iridium, ruthenium, and their alloys, the hydrogen flame must be retained, which, if costlier than coal-gas, is cheaper than carbonic oxide. In the use of gases as fuel the metal itself can be brought in contact with the flame, which is impracticable in case of carbon, and thus the great loss of heat is avoided which ensues when the crucible is heated from without. Their application renders it also possible to inspect the condition of the metal at any moment. In the metallurgy of the common metals these two advantages do not come into consideration. Carbon, moreover, is not only the cheapest but the most productive fuel, and the application of hydrogen as a source of heat seems therefore limited to autogenous soldering and to the fusion of the most refrac tory platinum metals. The property of platinum-black to ignite hydrogen, of which Döbereiner made a well-known and widely utilised application in his hydrogen lampin 1823, has lost its practical importance owing to the discovery of friction matches. The more intense and permanent was the interest which hydrogen created as a source of light. As the luminous power depends on the temperature at which a solid ignited body is maintained the suggestion was near at hand to produce an intense light by means of this gas, in which an incombustible body was heated to whiteness. To this end the Scotch military engineer Drummond used in 1826 cylinders of caustic lime heated in the oxyhydrogen flame. The Drummond light has been widely employed, not merely in geodetic measurements and in lighthouses, which the inventor had principally in view, but also for projections of microscopic objects and photographic images on glass, or drawings upon gelatine for demonstration in lecture-halls. || for dissolving views, "Ber chte über die Entwickelung der Chemischen Industrie Während des Letzten Jahrzehends." + Debray, Sur la Production des Températures Elevées et sur la Fusion de la Platine." Lecons de Chimie en 1861, 65; Paris, 1862. The calculated temperature of the flame of carbon in oxygen is 10,000°, from which has to be deducted the unknown amount of heat which at this temperature is lost by dissociation. See Debray, opus citat. 901. This Report, p. 14; also H. Vogel, Ber. d. Chem. Gesell., iii., you a short history of the manufacture, and if I am thought to be digressing from my path in first describing the history of cream or red-liquor caustic, it must be remembered that this was the forerunner of white, and that the development of the one led to the manufacture of the other. Le Blanc's process as originally devised was for the production of carbonate of soda only, and was intended as a substitute for kelp or Spanish barilla; and when the artificial soda was introduced as vat-liquors simply evaporated to dryness and containing a large quantity of caustic soda, the presence of this latter compound was found seriously to interfere with the application of this variety in many processes where Spanish barilla or kelp was formerly used. In the manufacture of soap, which was then a large trade, the presence of caustic soda in the commercial sodaash was rather an advantage, as the soap lyes were produced by the soap maker himself by boiling a weak solution of soda-ash with lime, but for many purposes the caustic soda in the ash had to be carbonated, and the idea occurred to Gossage in 1853, or perhaps before that time, of separating the carbonate and other foreign salts by concentration and other means now well known, and leaving the hydrate in solution as red-liquors, from which solid caustic soda could be obtained by concentrating sufficiently. Soon after this solid caustic soda entered the market, and became as staple an article of commerce as soda-ash had already become. The first attempts were what we should now call bad or discoloured caustic, and various means were patented from time to time to free the liquors from sulphides of both iron and sodium, and so produce caustic soda of good quality. In 1855 Stott patented a process for freeing vat liquors from sulphides by means of the oxides of iron, manganese, or zinc, and exactly the same thing was patented in 1857 by Gossage, and in subsequent years by many others. In 1857 we have a method patented by Bakewell for packing caustic soda in sheet iron drums, the article before that time being chiefly solidified by pouring it upon iron plates, breaking up and packing in casks or barrels. In some works after packing thus, the cask was filled up with the fluid caustic from the pots. About this time the demand for caustic soda must have been greater than the supply, for we find manufacturers Wagner, "Lehrbuch der Technologie." 9th edit., ii., p. 377. Journal of Cas-lighting, 1869. From the Journal of the Society for the Promotion of Scientific Industry. turning their attention to the causticising of liquors by means of lime. Still this was only to supply the increasing demand for what we should now call "cream caustic," as no other kind but one was known then, and in 1858 four Thomas's obtained a patent for causticising with lime and oxidising the sulphides with air in one operation. The increased dilution of the liquors then began to tell upon the cost of production, and in 1859 Dale obtained a patent for the process of concentrating the weak caustic liquors in steam boilers, and using the steam for various purposes. Many were the patents obtained between 1853-1860 in connection with the manufacture of caustic soda, but they are of little interest, and no real improvement was made until some time after November, 1860, when Ralston patented the following improvements :-"If it is desired to produce a hydrate of great strength, evaporating and separating the foreign salts, but in place of keeping the heat low as hitherto, the evaporation is continued and the heat raised until the iron separates as oxide of iron, and until the oxide is precipitated to the bottom of the vessel, the clear alkali is then separated from the iron. The alkali will then be free from iron and of great strength." It was also added that if the alkali was not required of so high a strength salt was to be added while in dry fusion, or in preference the foreign salts were not to be separated in the first instance. This may be considered as the commencement of white caustic; that it was ever made before this is extremely improbable, from the fact that the early manufacturers used very thin pots for concentrating and finishing, and a manufacturer would scarcely have ventured to raise four or five and even six tons of caustic soda in them to the state of igneous fusion, and have kept the pot at that temperature during the time necessary for the setting of the oxide of iron. Again, it was known to most of the caustic soda manufacturers of that day, that the best colour was produced when the samples contained most water and a minimum of neutral salts; so they dared not concentrate to much above 60 per cent of alkali for fear of deteriorating their colour, and so producing an unsaleable article. Even for some time after Ralston's patent fused or white caustic soda was very slightly known; the only publication concerning it of which I am aware was written by Dr. Pauli, and appeared in the CHEMICAL NEWS for 1862. Norman Tate mentioned this paper in an article to the Pharmaceutical Journal, September, 1862, which article was founded on a very interesting paper on caustic soda, read by Mr. Tate before the members of the Liverpool Chemists' Association, May 15, 1862; but white or fused caustic was but barely alluded to in his paper. Dr. Pauli, however, clearly indicated the process in June, which is followed to the present day. In the early days of the white caustic manufacture, it was produced in some places by dissolving and causticising a soda-ash, and, in others, from diluted vat liquors; but in Richardson and Watts's "Technology" Pauli states the method used at the Union Alkali Works, St. Helens, where commercial caustic soda (presumably that obtained from the red liquors of Gossage's process) was "heated to fusion, and kept at that temperature through the night, when, besides the oxide of iron, the alumina is separated as a crystalline silicate." This separation of alumina as a silicate I have never found to be the case with caustic from vat liquors causticised with lime, but from theoretical considerations there is a possibility of its happening with caustic from fused red liquors, which often contains a large proportion of silicate of soda. About this time Messrs. Gaskell, Deacon, and Co. patented a process for producing crystals of caustic soda, of which an analysis is given in Richardson and Watts's "Technology;" but these crystals never became a commercial success. At the International Exhibition of 1862, there were several samples of caustic soda exhibited, some of which were undoubtedly cream, others were fused, and some among this latter class were easily detected by possessing the greenish tinge due to over nitreing. The Jarrow Chemical Company, South Shields, exhibited caustic soda from the Newcastle district, while Lancashire was represented by Messrs. Gaskell, Deacon, and Co., Messrs. Hutchinson and Earle, Messrs. Roberts, Dale, and Co., and the Messrs. Muspratt of Liverpool, Flint, and Widnes. One exhibit came from the works of the Sambre and Meuse Joint Stock Mining Company. From Austria there were several exhibits of caustic soda; the sample exhibited by Messrs. Miller and Hochstadter being specially mentioned by the jurors as being very white. Since this time the manufacture has become wonderfully extended; one firm in Widnes, when in full work, turning out equivalent to 250 tons of 60 per cent caustic per week, and several others from 60 to 80 tons each weekly. In St. Helens there are four or five works, with a weekly turn out of from 60 to 80 tons of 60 per cent each, and all this by causticising vat liquors with lime, which contrasts very unfavourably with the statement in Wagner's Technology," that "the use of lime for the transformation of sodium carbonate into caustic soda has been abandoned long since" (1873). 66 Such is the history of white caustic soda. I will now turn to the present mode of manufacture in its most scientific form, starting with the black-ash process, and will divide the subject into five divisions, taking them as separate portions of one great whole. 1. Black ash-making; 2. Lixiviating the black-ash; 3. Causticising; 4. Concentrating; and 5. Finishing. 1.-The Black-ash Process. Black-ash, as is well known to practical men, is made by fluxing together a mixture of salt cake, carbonate of lime in various forms, and slack. There are two sizes of balls generally worked in the trade and designated by the amount of salt cake the mixing contains. The first are of small size and are called twenty (stone balls because they contain 2 cwts. of salt cake; the second are of larger size, and are called twenty-four stone balls because they contain in the mixing 3 cwts. of salt cake. In balls where the carbonate of lime is introduced as limestone the weight of this latter per ball is generally that of the salt cake employed; in some cases it is more, especially when used in the manufacture of caustic soda and in this case the proportion of slack is also more than when a soda-ash is made. For caustic soda when twenty stone balls are worked the following is a mixing from actual practice :— Salt cake Limestone Slack.. 2'5 cwts. 2.75" 1'5 1625 to 175 " The number of balls drawn in different works varies con siderably; some draw twenty-five small balls in the twentyfour hours from each furnace, whilst it is said that some draw from thirty to thirty-three; but when twenty-four stone balls are worked the general rule is twelve balls on the day shift and thirteen on the night turn. This is considered as good work, which should be performed regularly, producing a good and regular black-ash, lixiviating easily and containing a minimum of sulphate and sulphide. Where chalk is used as the source of carbonate of lime, an extra quantity is required to make up for the water present, but as chalk is not used in the Widnes, St. Helens, or in the Manchester districts, the two former being the great seats of the caustic soda manufactures it is not necessary to enter into details. But where white caustic soda is made, the black-ash ball is compounded of several materials not included in the foregoing mixings. The lime mud from the causticising operation is made to replace its equivalent of limestone, and the salts which are separated at various stages of the concentration of the causticised liquors are also added in quantity varying with the rate of production. In one works, where twenty stone balls were drawn, and making nothing but white caustic soda, the black-ash was made from the following mixing:- THERE are so many varieties of tea imported into this country that, in order to ascertain their distinguishing chemical characteristics, it is necessary to analyse a large number of samples. I have, therefore, determined to supplement a paper I published some months ago by the results of a large number of analyses made since. The samples I have examined comprise, as well as the ordinary teas of commerce, certain rarer kinds, the characteristics of which are less generally known, and which will, perhaps, possess some interest for my brother Analysts. The moisture of teas is generally considered a matter of little moment, and consequently is seldom determined. It would appear, however, that it bears a certain relation to the individual kind of tea, and that its limits of variation are wider than is generally supposed; as I have found the proportion as low as 4'20 per cent, and as high as 10.80 per cent. Tea is hygroscopic, and, when exposed to the air, after having been dried at a temperature of 212° F., will gain weight with considerable rapidity. The table (see next page) shows the results of some teas CHEMICAL NEWS, Oct. 1, 1875 so dried and then exposed to the atmosphere of my laboratory during parts of the months of February and March in this year. It will be seen that the Hysons and Gunpowders, both of which are high-dried teas, contain the smallest amount of moisture-the two Hysons yielding, respectively, 5.68 per cent and 4.84 per cent, and the highest percentage yielded by a gunpowder being 6:55 per cent, and the lowest 4'94 per cent; while the Congous (which have already been dried at a lower temperature) give an average of 8.50 per cent. The average of the entire table is 767 per cent. The average weight of water re-absorbed after 11 days' exposure to the air is 6'93 per cent, deducting which from 7.67 shows that, taking the average, the samples regained by exposure to the air all their original weight of moisture, less o'74 per cent. The different classes of tea showed, however, strikingly different results. For instance, one sample of Congou, originally rather dry, gained moisture to the extent of 175 per cent in excess of its original moisture. Every original weight, the average loss being about 17 per cent. other sample of Congou except one failed to reach its Similarly, the Pekoes in every case but one show an ultiOn the other hand, mate loss to nearly the same extent. the high-dried teas, Hysons and Gunpowders, show an increase in every case, averaging more than 1 per cent. The general tendency of this exposure to the air serves to bring the moisture of the whole to an average of about 7 per cent; but the limit of difference after exposure is very much narrower than before, the range of moisture before drying being 5'96 per cent, and after drying and exposure to air, 2.62 per cent. In my previous paper I gave the results of the partial analysis of the ash of twentyfour samples of genuine tea of ordinary character, and also of four samples of special growths of tea. The list of ordinary teas may with advantage be increased, and for the information of those who may not be familiar with the appearance of the rarer teas, it is yet more important to record the chemical results of such samples. I therefore subjoin a tabulated statement showing the results of the analysis of seventeen more samples of ordinary teas, and of eighteen samples of what I may term uncommon, or special teas. The number attached to each remains constant to the respective sample in the other tables which I give. The "special" teas were all taken from original packages, and had, therefore, undergone no manipulation in this country. They were mostly of high price, and, being only imported for the purpose of "mixing," would not by themselves yield a pleasant infusion. These analyses have all been made on a uniform plan, viz., igniting 100 grains of the tea, boiling the ash in 5 ounces of water, and washing on the filter with cold water. The alkali is estimated by adding excess of normal acid and titrating back. Ordinary Teas from Original Chest. |