386 ■ CHEMISTKY. 



The detection of small quantities of carbouous oxide may be effected 

 in a room, for example, by drawing tbe air over i)owdered glass mois- 

 tened with diluted blood, shaking the blood wiih a drop of ammonium 

 suli^hite, and examiniag by the spectroscope. Strips of pai)er moistened 

 with a solution of 0.2 gram palladium chloride in 100 cubic centimeters 

 water may be used to detect this gas. If the dried slips are hung in a 

 flask on a wire of platinum, the flask containing a little water, and corked, 

 black, shining deposit of metallic i)alladiuiu appears on the paper in a 

 few minutes, if five parts of carbonous oxide be present. If 'only one 

 l)art be present, from 2 to 4 Lours are required. If only half a part, 

 from 12 to 24 hours. {Nature, June, 1881, xxiv, 112.) 



Hawes has examined the liquid contained in the cavities of the smoky 

 quartz from Branch ville, Conn. This quartz is so full of cavities con- 

 taining condensed gas that a report like the explosion of a percussion 

 cap takes place when a fragment is knocked off with a small hammer. 

 When heated it decrepitates with such violence that bits fly whistling 

 through the air to a distance of twenty feet. The cavities contained 

 water, liquid carbon dioxide, and its gas, as was proved by the disap- 

 pearance of the liquid at 31° C, the critical point for CO2. Moreover, 1 he 

 cavities were large enough and sufficiently numerous to enable an anal- 

 ysis of their contents to be made by Wright, who found the gaseous 

 contents to consist of CO2 98.33, N 1.67, and H2S, SO2, Hgl^, F and CI 

 traces. The water present was in general 09.02 per cent, of the entire 

 inclosure approximately. Hawes accounts for the rapid motion observed 

 in some of their cavities by the alternations of evaporation and conden- 

 sation produced by minnte changes of temperature. {Am. J. ScL, March, 

 1881, III, xxi, 203, 209.) 



Monnier has presented to the Physical Society of Geneva an ingen- 

 ious apparatus, called an automatic methanometer, or fire-damp indica- 

 tor, designed for nse in mines. The 'fire-damp in presence of air in ex- 

 cess is decomposed in a glass vessel by an incandescent platinum wire, 

 and the change of volume producd acts directly on a mercury manom- 

 eter with platinum contacts. Every hour or half hour the air of the 

 mine is forced into the burner by a bellows, automatically. The result 

 of the test is registered, also automatically, in the central office. {Nature, 

 June, 1881, xxiv, 112.) 



C. W. Siemens has read a paper before the Birmingham meeting of 

 the British Association of gas managers on the use of gas for heating 

 and lighting purposes, in which he maintained the need of improved 

 processes in the manufacture of gas, so as to produce a gas of higher 

 illuminating power, and of improved burners, giving a higher temperature 

 of combustion, and therefore more light. He also advocated a separate 

 supply system of gas for heating purposes. {Nature, June. 1881, xxiv, 

 153.) 



Eemscu has shown that w^hen a mixture of iron by hydrogen, potas- 

 sium-sodium tartrate and metallic sodium is heated in a combustion 



