246 Mr. 11. Phillips's Additional Observations 



delighted to observe the summits of two very flat rhombohe- 

 drons, hollow within, and raised above the general level of the 

 ice, as shown at A and B in the annexed sketch, the axis of 

 the rhombohedrons being nearly perpendicular to the surface 

 Fisr. 1. Fiff. 2. 



of the plate of ice. When the plate of ice was exposed to 

 polarized light, it exhibited, in a direction perpendicular to its 

 surface, the positive uniaxal system of rings. 



It was impossible to obtain even the rudest estimate of the 

 an<des of the rhombohedron, owing to the warmth of the day, 

 and the distance which I had to carry the ice. 



The crystallization now described exactly resembled speci- 

 mens which I have seen of the Chanx carbonatec basee of Haiiy, 

 on the flat surface of which were formed several obtuse sum- 

 mits of the rhombohedron of calcareous spar, having their 

 axes perpendicular to that of the plate. 



Belleville, Feb. 19, 1834. 



XLIII. Additional Observations on the Use of Chemical 

 Symbols. By Richard Phillips, F.R.S. L. Sf Ed., Lec- 

 turer on Chemistry in St. Thomas's Hospital. 



To Thomas Graham, Esq., M.A., F.li.S.Ed., %c. 



Dear Sir, 



YOUR letter contained in the Philosophical Magazine for 

 February last does not, I regret to say, contain the in- 

 formation which I asked, nor dissipate the obscurities in which 

 symbols have shrouded your facts. I take the liberty, there- 

 fore, of addressing you more particularly on the subject, for 

 I am anxious to comprehend the steps by which you have ar- 

 rived at the important conclusions contained in your paper on 

 the arseniales and phosphates; and I shall avail myself of the 



