Miscellanies. 383 



one atom of sulphur, and one atom of chlorine, and that the red is a 

 bichloride, formed of one atom of sulphur and two atoms of chlorine. 

 — Rcv.Encyc. Juiii, 1832. 



8. Density of the vapor of sulphur and of -phosphorus. — The re- 

 searches of Dumas on these points, have also obtained the approba- 

 tion of the same distinguished chemists. 



To determine the density of the vapor of sulphur, chemists had 

 resorted to the known analogy of this substance with oxygen. Thus 

 the vapor of water is formed of one volume of hydrogen, and half a 

 volume of oxygen, whence it was concluded that sulphuretted hydro- 

 gen contained in like manner, half a volume of sulphur, and one vol- 

 ume of hydrogen. Now the density of hydrogen being 1.1912, that 

 of the vapor of sulphur should be 2.24.* Such was, in fact, the num- 

 ber generally adopted. Dumas, however, in several experiments 

 conducted with great care, found it to be just about three times as 

 great, which induces him to believe that there is only one sixth of 

 the vapor of sulphur in sulphuretted hydrogen, as in sulphurous acid. 



Phosphorus was subjected by Dumas to similar trials, and the 

 density of its vapor was in like manner, found to be different from 

 that deduced from the density and analysis of protophosphuretted 

 hydrogen gas, agreeably to the supposed analogy between phospho- 

 rus and azote. The density, by direct measurement, has been found 

 to be 4.32, the double of that generally accepted. — Idem. 



9. Preservation of substances by means of alkalies. — M. Payen 

 has preserved, during many months, polished instruments of iron and 

 steel by keeping them in solutions of potash or soda, — saturated so- 

 lutions diluted with one, two or three times their weight of water. 

 He at first thought that the preserving power depended upon the dis- 

 appearance of the air and carbonic acid in the alkaline mixture, 

 but he afterwards concluded that alkalinity acted an essential part in 

 the phaenomenon. In fact a very small quantity of alkali is sufficient; 

 — thus 2oVo snd even gnVo of caustic potash in water, will preserve 

 from oxidation, bars of iron, &ic. immersed in it. Lime water di- 

 luted with its own weight of water, or of course without dilution, 

 answer the same purpose. Alkaline carbonates and borax have the 

 same effect, but they must necessarily be stronger. — Rev. Encyc. 

 Aout, 1832. 



* These numbers are different from those heretofore used, and we have not 

 cess to the authority. — Ed. 



