Roijal Society. 495 



W. procured some grains of the original specimens from the 

 British Museum, and from Mr. Hatchett ; and notwith- 

 standing the smallness of the quantity, he succeeded in 

 proving them to be radically the same metal. 



Dr. Wollaston also read another ingenious paper discover- 

 ing a method of constructing a gonyometer for measuring 

 the angles of crystals by means of reflection, with micro- 

 scopes, which enable the observer to ascertain accurately 

 the angles of crystals, whether rough or smooth. Dr. W. 

 applied this useful instrument, of which a drawing was ex- 

 hibited, to crystals of carbonate of lime. 



A mathematical paper by Mr. Ivory was laid before the 

 Society. 



June 1.5. — A paper by Sir James Earle was read, de ] 

 scribing a stone in the bladder, which occupied its whole 

 contents, and weighed 44 ounces. 



The Society for improving animal chemistry furnished a 

 paper by Mr. Brande, detailing the results of a series of ex- 

 periments on animal mucus and albumen exposed to gal- 

 vanic electricity. 



A paper by Dr. Pearson, on expectorated matter, was read. 

 It appears from the Doctor's experiments, that the different 

 kinds of expectorated matter differ rather in the proportion of 

 the ingredients than in kind. They all consist of albuminous 

 matter, water, and the two principal ingredients are muriate 

 of soda and potash neutralized by animal oxide, if not by 

 a destructible acid, besides a small proportion of phosphate 

 of lime, ammonia, carbonate of lime, and probably phos- 

 phate of magnesia and siliceous earth. The Doctor an- 

 nounces that potash neutralized by animal matter is con- 

 tained in the blood, and in most or all of the secreted and ex- 

 creted fluids, namely, in dropsical water, pus, both that se- 

 creted without breach of surface as well as that of abscesses, 

 and in the urine, See. He has not found ihe soda, as repre 

 sented by former chemists, to impregnate the animal fluids ^ 

 and this he seems to think might have been concluded a 

 priori, because it is admitted on all hands, that almost every 

 kind of vegetable food contains the potash united to some 

 matter destructible by fire, which is not the case of soda ; 

 3 and 



