310 Intelligence and Miscellaneous Articles. 



in the first, and a more considerable one in the second, which ap- 

 peared to be composed chiefly of tartrate of lime and vegetable 

 colouring and extractive matter, without oxide of antimony. — 

 Jameson's Journal, Dec. 1828. 



NITRATE OF SILVER AS A TEST FOR VEGETABLE AND ANIMAL 

 BTATTER. 



Dr. Davy states, that nitrate of silver dissolved in pure water is not 

 altered by the sun's rays. If the minutest quantity of vegetable or 

 animal matter is present, the solution is discoloured; and, with com- 

 mon distilled water, the discolouration is strong. To prove that the 

 cause of the change of colour is the one assigned, it is sufficient to al- 

 low the coloured matter to subside, decant the colourless solution, and 

 expose it again to sunshine. However powerful the sun's rays are, 

 no further effect is produced ; but add more common distilled water, 

 and the phaenomenon will instantly reappear. He believes nitrate of 

 silver thus used is one of the best tests of the presence in water of 

 very minute portions of vegetable matter; of course, any chloride of 

 silver that may be formed in consequence of the presence of any 

 muriates, should be allowed to subside in the dark, and the sub- 

 sidence should be complete before the fluid is decanted and exposed 

 to light. — Ibid. 



SOLUBILITY AND MELTING POINT OF PHOSPHORUS. 



Dr. Davy dissents from the common opinion, that phosphorus is 

 insoluble in water : a piece of phosphorus immersed for twenty-four 

 hours in distilled water imparted to it, even after it was filtered, a 

 smell of phosphorus, and it was even perceptibly luminous in the 

 dark. With respect to the melting point of phosphorus, Dr. Davy 

 observes, that according to Pelletier it melts at 99° ; according to 

 Dr. Thomson, at 108°: the phosphorus, however, which Dr. D. 

 tried melted at 112°; at 110° he has found it brittle, and very easily 

 reducible to powder. Gradually and very slowly cooled in a solution 

 of potash, phosphorus may remain liquid at 72°, but when touched 

 with the thermometer it became instantly solid. — Ibid. 



[Although I have no doubt that phosphorus was actually dissolved 

 in the above-mentioned experiment, yet, as I have endeavoured to 

 prove in the Annals of Philosophy, it exists, in the solution 1 beheve, 

 in the state of phosphuretted hydrogen. — R. P.] 



ACTION OF SULPHURETTED HYDROGEN GAS ON SOLUTIONS OF 

 MERCURY. BY M. ROSE. 



The precipitate obtained by the action of sulphuretted hydrogen 

 on a solution of chloride of mercury remains long suspended in the 

 liquid, to which it imparts a milky appearance; it is very difficult to 

 filter, it dries readily, and then much resembles white precipitate of 

 mercury. At a high temperature it is decomposed ; if it be slowly 

 heated in a glass tube closed at one end, chloride of mercury first 

 sublimes, and afterwards sulphuret of mercury. This compound 



perfectly 



