146 



ner described. Heated to the temperature of 212° F., it does not 

 part with any of its water of combination. For estimating the amount 

 of platinum and chlorine, the salt was fused with carbonate of potassa, 

 &c, and the platinum, thus obtained, weighed by itself, and the chlo- 

 rine precipitated from the solution by nitrate of silver. 



The quantity of nitric oxide was determined by introducing a por- 

 tion of the salt into a graduated tube, inverted over mercury, and 

 decomposing it by letting up the requisite proportion of water. 



The mean of a series of experiments, varied in different ways, gave 



Platinum, - 41.26 per cent. 

 Chlorine, - 43.89 « 

 Nitric oxide, 4.98 " 



The above results correspond to five atoms of bichloride of plati- 

 num ; five atoms of hydrochloric acid, and two atoms of nitric oxide. 

 The water was calculated from the loss, in the analysis, to be equiva- 

 lent to ten atoms. 



Respecting the chemical nature of this compound, it may be re- 

 garded, either as a chloride of platinum, with a muriate of nitric ox- 

 ide, represented by the following formula, (Pt CI 2 ) 5 -f- [(CI H) 5 

 + (NO 9 ) 3 ] + 10 Aq, or as a double chlorosalt, a chloroplatinate of 

 nitrogen, with a chloroplatinate of hydrogen, represented by the for- 

 mula, [(Pt CI 2 ) 3 + N CI 2 ] 3 + (Pt CI 2 + H CI) + 14 Aq. 



Professor A. D. Bache made a verbal communication in which 

 he compared the observations on the magnetic dip by Pro- 

 fessor Loomis, contained in his paper ordered this evening for 

 publication, with those given in a paper by Professor Courtenay 

 and himself, read before the Society in 1834. 



Professor Bache remarked, that as some of the stations of a series 

 of observations for magnetic dip made by Professor Courtenay and 

 himself, and published in the fifth volume of the Society's Transac- 

 tions in 1835, were the same as those of the series of Professor 

 Loomis, about to be published, it might be of interest to compare the 

 results. The annexed table was given as containing the places, dates, 

 and results of observations in the two series. 



