948 THE COLLIERY GUARDIAN May 19, 1916. CURRENT SCIENCE Estimation of Ammonia. Mr. G. E. Foxwell describes, in the Gas World, a new method of estimating ammonia, based on a colorimetric reaction discovered by Berthelot 60 years ago. If excess of phenol and a little sodium hypochlorite are added to a solution of ammonia or its salts, a blue coloration is produced. The writer has found that as a qualitative test this method is extremely sensitive, less than one ten-thousandth part of a milligramme of ammonia giving a distinct coloration. Thomas has pointed out the possi- bility of using this reaction as a quantitative test, but somewhat meagre details are given in the source above referred to. Desiring to obtain a rapid method of estimating ammonia in waste liquor, the writer has gone into this test thoroughly, and, having determined the conditions necessary to make the reaction quantitative, and made sundry modifications, now presents it in the hope that it may prove useful to others. The test is carried out as follows :—Pure ammonium chloride is prepared, and 0-063 gramme is dissolved in distilled water, and the solution made up to 1 litre. Thirteen test tubes of as nearly as possible equal bore are taken, and varying amounts of NH4C1 solution run in from a burette. In the first test tube is placed 0-1 c.c. of this solution, into the second 0-3 c.c., into the third 0-5 c.c., then 0-7 c.c., Ic.c., 1-5 c.c., 2 c.c., 2-5 c.c., 3 c.c., 3-5 c.c., 4 c.c., 4-5 c.c., 5 c.c. The quantity pre- sent in each test tube is then made up to 5 c.c. with distilled water. To the solutions thus prepared, 1 c.c. of a 4 per cent, solution of phenol, and 1 c.c. of a dilute solution of sodium hypochlorite are added. It is necessary to heat the solution before any blue coloration appears, and the writer has found that every- thing depends on the mode of heating. Thus, if the test tube is heated to boiling slowly over a small flame, the coloration is much more intense than if heated quickly. In order to ensure that each experiment shall be done under th.fe same conditions, it will be found advisable to immerse the tubes in a beaker of boiling water for at least minutes. This will be sufficient to bring out the full colour. It does not appear to make any differ- ence to the colour if this heating in boiling water is con- tinued for some time. It is important to note that once the phenol and hypochlorite have been added, no ammonia is evolved on boiling the solution, even if the ammonia was present in the first place as hydrate (NH40H). The specimen tubes thus made up and coloured by immersion in boiling water appear to keep their colour indefinitely. In order to test a sample of waste liquor for total ammonia, 5 c.c. 'are taken, and made up to 300 c.c. with distilled water. Five c.c. of this solution are pipetted into a test tube, and 1 c.c. of 4 per cent, phenol solution, together with 1 c.c. dilute sodium hypochlorite. The mixture is heated in boiling water as before, cooled under the tap, and the colour compared with the stan- dard tubes. If the proportions of both free and fixed ammonia are desired, 5 c.c. of the liquor are boiled to expel free NH3, and the solution is then made up to 300 c.c., and treated as before. It may seem at first sight hopeless to expect a colour test to be of any use in connection with waste liquor, but at the dilution employed the coloration is so slight as to be negligible. For simplicity, the following table is given showing the percentage of ammonia in waste liquor, assuming every operation to be carried out exactly as detailed •above :— C.c. standard NH,C1 solution in tube. 0'1 nh3 in liquor. Per cent. 0'0024 0'3 0'0072 0'5 0'012 0'7 0'0168 1'0 0'024 1'5 0'036 2'0 0'048 2'5 0'06 3'0 0'072 3'5 0’084 4’0 0’096 4'5 0’108 5’0 0’12 It was found that free acid must not be present, or the test fails altogether. Free lime has no influence whatever. Specimen results :— (1) (2) (3) Per cent. Per cent. Per cent. Ammonia by colour...... 0 010 ... 0'052 ... 0'026 ,, „ distillation 0'012 ... 0'050 ... 0'025 The test is not as accurate for ordinary works purposes as the distillation method, but is accurate enough to show at a glance how the stills are working, as, assuming the solutions to be made up, only three or four minutes are required for the test. For the estimation of larger quantities of ammonia, the writer would not recommend this method, as owing to the great dilution required, any error is considerably magnified. Thus the percentage of ammonia in a liquor was estimated by the. colour method as 1-88 per cent., whereas by distillation only 1-77 per cent, was found. Copper Oxide in Analysing Gas Mixtures. Messrs. G. A. Burrell and G. G. Oberfell (Journal of Industrial and Engineering Chemistry) deal with the fractional combustion of hydrogen and carbon monoxide in gas analysis by means of copper oxide, and describe the apparatus used. The copper oxide method has given better satisfaction than methods using acid or ammoniacal solutions of cuprous chloride for determin- ing carbon monoxide, or of palladium asbestos, palladium sponge, or colloidal palladium solution for determining hydrogen. AND TECHNOLOGY. A great advantage of the method over the use of absorbents for carbon monoxide and hydrogen is the elimination of the preparation of solutions, and the fact that copper oxide does not become poisoned, as at times do some palladium preparations that are used for the hydrogen determination. Cuprous chloride solutions for the carbon monoxide determination are somewhat tedious to prepare, and have a small absorption capacity. Copper oxide, on the other hand, lasts for practically an indefinite number of determinations, and is easily restored to activity, when partly reduced, by drawing air over it when hot. The copper oxide is contained in a U glass tube (inside diameter, 4 mm.) surrounded by an electrically heated oven, which is supported by a standpipe, by means of which it can be raised from the copper oxide tube when not in use. Copper oxide that passes a 100-mesh sieve is not used in the tube. One U tube used contained 3'3 grammes and a free space volume of 1’89 c.c. The ovens in use by the authors require about 2-4 amperes at 30 volts. Connection is made through regulating resistances to the 220 volt lighting circuit of the building through a lamp bank rheostat. The current is switched on at the beginning of an analysis, so that the oven will be heated to the desired temperature (275 degs. to 300 degs. Cent.) by the time the analyst is ready to make the fractional combustion analysis. The gas mixture is slowly passed back and forward through the copper tube between the burette and slow- combustion pipette until no further diminution in volume is noted by reading the gas volume in the burette. The authors have found that a maximum of about 15 minutes is required to burn completely the carbon monoxide and hydrogen in various gas mixtures. Carbon monoxide burns readily in the presence of hydrogen, but much more slowly when burned alone. After combustion is complete, the electric oven is raised from the copper oxide tube, and the latter allowed to cool. The cooling is hastened by playing a blast of cold air from a com- pressed air pipe on the tube, the operation requiring about five minutes. A safe way is to make a second reading of the gas volume after a few minutes’ time, to make sure that no further contraction, due to cooling, takes place. Next the carbon dioxide is removed by passing the gas mixture into the caustic soda pipette. Gas in the train and copper oxide tube containing carbon dioxide is swept into the pipette. After the hydrogen and carbon monoxide have been determined, the residual gas is passed into the caustic soda pipette for storage. Enough oxygen to burn the paraffin hydrocarbons is then drawn into the burette, measured, and passed into the slow combustion pipette (not through the copper oxide tube) and the platinum spiral heated to a white heat. Next the residual gas is drawn from the soda pipette into the burette and passed at the rate of about 10 c.c. per minute into the slow combustion pipette. Slow combustion takes place as the gas enters, and an accumulation of an explosive mixture cannot take place. After the combustion is complete, the resulting contraction and carbon dioxide are measured and the gas mixture again passed into the slow combustion pipette and burned again. Table I. shows analyses of two samples of gas, and compares the results obtained by burning the carbon monoxide and hydrogen with copper oxide with those from absorption by ammoniacal cuprous chloride solution and colloidal palladium solution. Table I.—Percentage Analyses of a Sample of Gas by Two Methods. Sample I. Sample II. Colloidal Colloidal palladium CuO palladium CuO and cuprous method. and cuprous method. chloride. chloride. 0'0 CO2 0'2 0'4 0’0 C2H4,etc. 44'6 44'6 .. 12’7 12'5 O2 1'7 1'6 0’2 0'2 CO 0'8 0'9 1’0 0'8 H, 7'7 6'7 .. 42'3 42'2 CH, ... 26'4 26’4 .. 41’2 41'1 CoH(i ... 11'4 11’2 .. .0'0 0'0 N 2 7'2 8’2 .. 2’6 ... 32 Table II. shows two analyses of the same ' sample. One was made by burning the hydrogen and carbon monoxide over copper oxide; the other by burning the carbon, monoxide, hydrogen and methane together in a slow combustion pipette of a Haldane gas analysis apparatus. With the latter, gas volumes as small as 0'002 c.c. can be measured. Table II.—Percentage Analyses by Copper Oxide and by Triple Combustion. Analysis by Copper Triple oxide. combustion. COo 3'9 3’90 C2H„ etc 0'0 0’00 Oo ....: .... 15'5 ... 15'46 h; 0’0 0'02 co 0'3 0'17 CH, 0'9 0'84 n2 .... 79'4 ... 79'61 Scientific Research. At the first meeting of the Standing Committee on Metallurgy appointed by the Advisory Council . for Scientific and Industrial Research, Sir R. Hadfield, as chairman of the Ferrous Section, called attention to the necessity for improvement and progress in the metallurgy of iron land steel. Though Great Britain had been far from backward in this field, there was now room for a .great extension of research, in which there would be a happy combination of science and practice. The further progress of metallurgy depended largely on the securing of supplies of the special alloys and materials required, and there was now need for a central clearing-house in order that as soon as new knowledge was secured as to valuable products in any part of the Empire, it should be made available for British industry. No foreign control of such products should any longer be permitted. Sir Robert called attention to the series of special reports on the mineral resources of Great Britain now being issued by the Geological Survey, and urged that similar information for the whole Empire should now be made available through one central source. He directed atten- tion to a number of subjects upon which more light was needed—for example, the production of sound steel; the discovery of new alloy steels and the development of the older types; wider study of crystallised structure and examination by photomicrography with increased magni- fications ; more accurate determinations of high tempera- tures, including the improvement of electrical and optical pyrometers; the improvement of electrical furnace practice; the improvement of methods of hardening; the improvement of the permeability and other electrical and magnetic qualities of various alloys, and the correlation of the mechanical and magnetic properties of steel; corrosion refractory materials, especially with a view to rendering ourselves independent of foreign supplies. THE LAWRENCE WATER HEATER AND SOFTENER. The combined water softener and heater made by the Lawrence Patent Water Softener and Sterilizer Com- pany, carries out the processes of softening and heating water in the one apparatus. No lime is required, and the cost of running is practically nil, waste exhaust steam being used, so that apart from the economy in fuel and maintenance effected by the reduction of scale forma- tion, there is a saving by the utilisation of waste steam in heating the water, and also a recovery of water by the condensation of the exhaust steam. The apparatus removes the carbonate hardness from the water, and at the same time heats the latter to about 210 degs. Fahr. The carbonates being deposited in the solid form on removable “ locator ” plates, with- out the necessity of using lime, no lime sludge has to be dealt with. The action of the heater-softener is as follows :—The hard cold water is admitted by a control valve A (see figure), and enters through the top cover of the plant, where it falls upon perforated water-locked trays. Pass- ing through these in divided streams, it falls next upon groups of specially-formed plates or “ locators,” which continue to divide it up into fine streams (by means of their serrated edges) as it descends from plate to plate. Exhaust steam is admitted through E at the base of the plant, and after passing through a steam cleaner, traverses a series of distributing nozzles F, and meets the descending streams of divided water, as described above. A very thorough mixture of the rising steam and descending water is thus obtained, and the temporary hardness of the water is reduced to within about 4 degs. by the carbonate salts being deposited on the “ locator ” plates. The softened and heated water passes down into a chamber in the base of the plant, and from there to the outlet. The “ locator ” plates may be easily removed from the plant in a few minutes without taking the latter apart, and the deposit, which will usually be found to be in a friable condition, can be dislodged’by tapping the plates. The American Coal Refining Company is reported as con- templating the development of cannel coal property in Benton and Morgan counties, Missouri, for a daily output of 1,000 tons, utilising the coal in the manufacture of coal tar pro- ducts, including dyes, crude benzol, by-products for manufac- turing explosives, for treating raw leather, to solidify motor- car tyres, to manufacture illuminating gas, etc. The same company is now operating a coal refining plant near Denver, using Colorado lignite, from 500 tons of which it has a daily production of 2,107 gals, of benzol, 2,767 gals, of creosote, 1,625 gals, of pitch, etc.