CHEMISTRY. 



weighing. The temperature obtained when the 

 snow is wet is almost as low as when it is dry, 

 which is not the case when hydrochloric acid 

 alone is used. When working at a tempera- 

 ture near zero, the spent acids answered as 

 well as, if not better than, hydrochloric acid ; 

 but when endeavoring to obtain lower tempera- 

 tures than 30 C. by previously cooling the 

 acid, better results were obtained with hydro- 

 chloric acid. 



Out of a large number of chemical com- 

 pounds experimented upon, Prof. William 

 Thomson has found that those having the 

 most remarkable antiseptic properties are the 

 compounds of fluorine, hydrofluoric acid, the 

 acid and neutral fluorides of sodium, potassium, 

 and ammonium, and the fluo-silirates of those 

 bases. Of these, sodium fluo-silicate is per- 

 haps the best suited for an antiseptic. It is 

 not poisonous, possesses no smell, and is spar- 

 ingly soluble in water. It has only a very 

 slightly saline taste, and may therefore be em- 

 ployed in preserving food without communi- 

 cating any taste to it. A saturated solution 

 containing O'Gl per cent, of the salt is not ir- 

 ritating to wounds, while it possesses great 

 antiseptic power for animal tissues. 



The value of phosphorus pentoxide as a dis- 

 infectant has been measured by Dr. Kinyoun, 

 in experiments on cultivations of the micro- 

 organisms of anthrax, yellow fever (Finlay), 

 typhoid fever, Asiatic cholera, and cholera 

 nostras, the nutrient medium being agaragar. 

 The cultivations were divided into series ac- 

 cording to the way they were covered. The 

 result of the experiments was the conclusion 

 that this substance is a surface disinfectant 

 only, having little, if any, penetrating power, 

 and is wholly unfit for fumigation and disin- 

 fection where penetration is desirable ; and 

 that its limited scope of usefulness is alto- 

 gether met in the use of bichloride of mer- 

 cury. 



P. Bockairy, in testing butter, substitutes 

 toluene for benzine. The test-tube is heated 

 to 50 C., and shaken up so as to mix the two 

 liquids. If the sample is a fat, turbidity im- 

 mediately occurs, but if it is butter, even if 

 mixed with fat, the two liquids mingle without 

 turbidity. The purity of the butter is deter- 

 mined by keeping the test-tube for half an 

 hour in water at 40 0. If the butter is pure, 

 there is no turbidity, but if it contains a 

 foreign fat, turbidity at once appears, and 

 ultimately a precipitate. 



From examinations of certain waters one 

 of them being a tv mineral " water free from all 

 possible sources of contamination Prof. E. H. 

 S. Bailey has been led to consider that free 

 ammonia may be sometimes a natural constit- 

 uent, and not indicative of any pollution, of 

 the water. 



Apparatus. For preserving constant the vacu- 

 um employed in fractional distillation, Gode- 

 froy uses two vertical tubes united at their 

 lower ends by a fine tube, of which, when 



they are not in use, one, A, is entirely filled 

 with mercury, while the other, B, contains 

 more or less mercury, according to the vacuum 

 desired. The tubes are so adjusted that as 

 soon, on making the exhaust, as the pressure 

 in B is less than will support the mercury 

 column in A, this column falls, and the mer- 

 cury rises in B till it cuts off the outlets con- 

 necting with the exhaust. 



A new form of apparatus for fractional dis- 

 tillation, by Dr. J. Tcherniac, in the technical 

 transformation of ammonium sulpho-cyanide 

 into calcium sulpho-cyanide, is described by T. 

 II. Norton and A. H. Otten. The novel feature 

 is the introduction of a device called a deter- 

 si'ii'i\ to prevent the frothing accompanying the 

 rapid distillation of the amraoniacal liquor. 



Edward Hart has devised a simple apparatus, 

 such as can be made by an amateur glass- 

 blower, for fractional distillation. The prin- 

 ciple of it is the familiar one of the "dephleg- 

 mator." The bent tube is so adjusted that the 

 condensed portion runs down and passes around 

 its inside at each bend, while the vapor passes 

 upward through the ring of descending liquid. 



In an apparatus by Ramsey and Young for 

 determining vapor-densities of solids and liq- 

 uids, a test-tube, having inserted from its top 

 a thermometer with its bulb covered with cot- 

 ton, is put in communication with a Sprengel 

 pump. The apparatus having been cooled and 

 exhausted, the liquid to be examined is allowed 

 to trickle down the thermometer and moisten 

 the cotton. The stream of liquid having been 

 cut off, the pressure and temperature are noted 

 as soon as they become constant. Air is then 

 admitted, and a second reading of pressure and 

 temperature is taken. If the experiment is 

 made with a solid, the bulb of the thermometer 

 is previously covered with it by dipping into 

 the melted substance. 



An improved form of apparatus for gas 

 analysis described by J. T. Willard is essen- 

 tially a combination of Elliott's and Frank- 

 land's apparatus for the analysis of gases in- 

 cident to water analysis, with important modi- 

 fications and additions. It was designed for 

 use with mercury, but admits the employment 

 of water. 



In W. Thomson's improved form of Lewis 

 Thomson's instrument for determining the cal- 

 orimetric value of fuels and organic compounds, 

 the substance is burned in a stream of oxygen 

 instead of with potassium chloride. 



A new apparatus for condensing gases by 

 contact with liquids, described by Prof. Lunge, 

 consists of a series of perforated plates made 

 of stone-ware, arranged in column. The gases 

 as they rise are brought into immediate con- 

 tact with an extensive plane surface of the 

 absorbing liquid. 



An electrolytic method for liquefying gases 

 is employed by H. N. Warren, which is de- 

 scribed as being better adapted than the usual 

 method, when a compound gas, like 1101, is 

 required. 



