117 



of the precipitate of nitrate of silver by iodide of potassium as it will 

 absorb. The collodian should be very thin and as transparent as 

 water. 



The following Gentleman was duly elected an Ordinary 

 Fellow. 



James Cunningham, Esq., W.S. 



The following Donations to the Library were announced : — 



Verhandlungen der Kaiserlichen Leopoldinisch-Carolinischen Aka- 

 demie der Naturforscher. 4to. — From the Academy. 



Journal of the Horticultural Society of London. Vol. VII., Part 1 . 

 8vo. — From the Society. 



Museum of Practical Geology : — On the Science of Geology and its 

 applications. By Andrew C. Ramsay ; — On the value of ex- 

 tended knowledge of Mineralogy and the Process of Mining. 

 By W. W. Smyth ; — On the Importance of Special Scientific 

 Knowledge. By John Percy, M.D. 8vo. — From the Museum. 



Monday, 1st March 1852. 



Right Reverend BISHOP TERROT, Vice-President, in 

 the Chair. 



The following Communications were read : — 



1. On some Salts and products of Decomposition of Pyro- 

 meconic Acid. By Mr James F. Brown. Communi- 

 cated by Dr Anderson. 



The pyromeconic acid employed in the following experiments was 

 obtained by distilling impure meconic acid at a temperature of about 

 600° or 600° Fahr., when there is obtained a highly crystalline sub- 

 limate of a dark colour and empyrcumatic odour. Its purification 

 was effected by pressing the crystals so procured between folds of 

 filtering paper, and finally subliming them at a moderate heat in 

 cylindrical glass vessels provided with paper diaphragms. As thus 



