560 Intelligence and Miscellaneous Articles. 



the greater part of a sphere two inches in diameter, the colours of 

 which are brilliant. 



The extreme rapidity with which gases pass through films of wa- 

 ter, has afforded in the hands of the same chemist a good method of 

 determining the condition of equilibrium and law of the transit of 

 gases. A series of papers communicated during the past and present 

 years to the American Journal of Medical Science, and Journal of the 

 Franklin Institute, contain a development of these laws. An illus- 

 tration from these researches will give an idea of their result. 



In an atmosphere containing 190 measures of nitrogen gas, a soap 

 bubble was expanded containing 190 measures of protoxide of nitro- 

 gen. The bubble collapsed with great rapidity, and at the end of 

 three minutes its contents were found to be 35 measures, the atmo- 

 sphere around it being 34?1 measures. On analysis it was found that 

 the constitution of the gas within and without the bubble was iden- 

 tical, one half being the protoxide and the other half being nitrogen. 



By thus measuring and analysing the contents of bubbles and the 

 atmospheres around them, the general law of equilibrium was proved 

 to be, that motion only ceased when the chemical composition on both 

 sides of the barrier had become alike. 



CHLOROSULPHURETS OF LEAD, COPPER, BISMUTH, AND ZINC. 



M. Reimsch, on passing sulphuretted hydrogen into a liquor con- 

 taining lead and acidulated with muriatic acid, obtained a blood-red 

 precipitate, which was collected on a filter, became of a red brown 

 colour, and when heated on charcoal with soda gave a globule of 

 lead. On leaving the precipitate a longer time in the liquor, and 

 adding more sulphuretted hydrogen, or on continuing a current of 

 this gas, the precipitate became black sulphuret. Free muriatic acid 

 appeared to be requisite to the production of the red-coloured preci- 

 pitate ; for a neutral solution of chloride of lead, or salts of lead with 

 excess of acid treated with sulphuretted hydrogen, always gave the 

 usual black precipitate. M. Reimsch satisfied himself that the pro- 

 duction of the red precipitate was always owing to nitric acid contain- 

 ed in the muriatic acid, and consequently to chlorine, and on using 

 muriatic acid free from nitric acid he obtained a yellow precipitate. 

 In order to produce the red precipitate, dissolve half a drachm of 

 neutral acetate of lead in seven ounces of cold distilled water ; add to 

 this solution, constantly agitating, seven drachms* of nitromuriatic 

 acid which has some days been prepared, by mixing two parts of con- 

 centrated muriatic acid with one part of concentrated nitric acid j 

 pass quickly through the solution a current of sulphuretted hydrogen, 

 which is to be discontinued as soon as the reddish yellow deposit has 

 become of a perfect cinnabar red. The yellow precipitate is obtained 

 by adding to the above-described solution of lead, seven drachms of 

 muriatic acid free from chlorine, taking care to agitate them well. 

 The following experiments show the nature of these precipitates. 



The Red Precipitate. — If this be boiled in water, it passes from the 

 granular state to that of a bulky red-brown powder; this suffers no 

 further change, and may be dried at 100° Fahr. without altering its 



