DETECTION OF ALCOHOL IN TRANSPARENT SOAPS.
By H. JAY.
It appears that every article manufactured with the aid of alcohol is required on its introduction into France to pay duty on the supposed quantity of this reagent which has been used in its preparation. Certain transparent soaps of German origin are now met with, made, as is alleged, without alcohol, and the author proposes the following process for verifying this statement by ascertaining--the presence or absence of alcohol in the manufactured article: 50 grms. of soap are cut into very small pieces and placed in a phial of 200 c.c. capacity; 30 grms. sulphuric acid are then added, and the phial is stoppered and agitated till the soap is entirely dissolved. The phial is then filled up with water, and the fatty acids are allowed to collect and solidify. The subnatant liquid is drawn off, neutralized, and distilled. The first 25 c.c. are collected, filtered, and mixed, according to the process of MM. Riche and Bardy for the detection of alcohol in commercial methylenes, with ½ c.c. sulphuric acid at 18° B., then with the same volume of permanganate (15 grms. per liter), and allowed to stand for one minute. He then adds 8 drops of sodium hyposulphite at 33° B., and 1 c.c. of a solution of magenta, 1 decigrm. per liter. If any alcohol is present there appears within five minutes a distinct violet tinge. The presence of essential oils gives rise to a partial reduction of the permanganate without affecting the conversion of alcohol into aldehyd.
ON THE CALORIFIC POWER OF FUEL, AND ON THOMPSON'S CALORIMETER.
By J.W. THOMAS, F.C.S., F.I.C.
A simple experiment, capable of yielding results which shall be at least comparative, has long been sought after by large consumers of coal and artificial fuel abroad in order to ascertain the relative calorific power possessed by each description, as it is well known that the proportion of mineral matter and the chemical composition of coal differ widely. The determination of the ash in coal is not a highly scientific operation; hence it is not surprising that foreign merchants should have become alive to the importance of estimating its quantity. While, however, the nature and quantity of the ash can be determined without much difficulty, the determination of the chemical composition of coal entails considerable labor and skill; hence a method giving the calorific power of any fuel in an exact and reliable manner by a simple experiment is a great desideratum. This will become more obvious when one takes into consideration the many qualities and variable characters of the coals yielded by the South Wales and North of England coal fields. Bituminous coals--giving some 65 per cent, of coke--are preferred for some manufacturing purposes and in some markets. Bituminous steam coals, yielding 75 per cent, of coke, are highly prized in others. Semi-bituminous steam coals, yielding 80 to 83 per cent, of coke, are most highly valued, and find the readiest sale abroad; and anthracite steam coal (dry coals), giving from 85 to 88 per cent, of coke (using the term "coke" as equivalent to the non-volatile portion of the coal) is also exported in considerable quantity. Now the estimation of the ash of any of these varieties of coal would afford no evidence as to the class to which that coal belongs, and there is no simple test that will give the calorific power of a coal, and at the same time indicate the degree of bituminous or anthracitic character which it possesses.
In order to obtain such information it is necessary that the percentage of coke be determined together with the sulphur, ash, and water, and these form data which at once show the nature of a fuel and give some indication of its value. To ascertain the quantity of the sulphur, ash, and water with accuracy involves more skill and aptitude than can be bestowed by the non-professional public; the consequence is that experiments entailing less time and precision, like those devised by Berthier and Thompson, have been tried more or less extensively. In France and Italy, Berthier's method--slightly modified in some instances--has been long used. It is as follows: