370 Miscellanies. 



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 chlorine 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 de- 

 composing it by letting up the requisite proportion of water. 



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

 Platinum, - - 41.26 per cent. 

 Chlorine, - - - 4.3.89 " 

 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 equiv- 

 alent 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 CP) s-j- [(CI H)^ + 

 (N02)2]-|- 10 Aq, or as a double chlorosalt, a chloroplatinate of ni- 

 trogen, with a chloroplatinate of hydrogen, represented by the formu- 

 la, [(Pt C12)2+N Cl"]2 -f-(Pt Cl^ +H CI) + 14 Aq. 



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

 compared the observations on the magnetic dip by Professor 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. 



The following resolutions in relation to combined magnetic obser- 

 vations were adopted : 



Resolved, That in the opinion of the American Philosophical So- 

 ciety, it is highly desirable that the combined series of magnetic ob- 

 servations now in progress under the direction of the British govern- 

 ment, should be extended to the United States, by the establishment 

 of Magnetic Observatories at suitable places. 



Resolved, That a Committee be appointed, with authority, on be- 

 half of the Society, to invite the attention of one of the departments 

 of the Government of the United States to the plan for combined 

 magnetic observations, a sketch of which was presented in the docu- 

 ments from a Committee of the Royal Society of Loudon, and to urge 

 co-operation in the plan as a national undertaking, in every way wor- 

 thy of the United States.* 



* A Committee were appointed, and a letter or memorial on the subject drawn 

 up by them was addressed to Hon. J. R. Poinsett, Secretary of War. This letter 

 is given at length in the Proceedings, but as it failed to effect its object at the pro- 



