Ajialysis of the Coprolites of Birds. M 



2d. The phosphate of lime and triple phosphate were con- 

 verted into phosphate of lead, each separately. The phosphate 

 of lead from the phosphate of lime was then fused before the 

 blowpipe. It cooled into a fine crystalline mass, as phosphate of 

 lead should. The phosphate of lead from the triple phosphate 

 was fused and the flame continued. It burned oflf with a beau- 

 tiful phosphorescent green-yellow flame, and the lead was re- 

 duced. I have spread the facts before you. The phosphoric 

 acid does not exist in traces only, but forms a very large portion 

 of the coprolite. Now this substance is too precious to be wasted 

 in further trials for phosphate. I want to reserve as much as I 

 can for other points, 



[The next communication, dated Nov. 21st, presents the evi- 

 dence of the existence of urates in the coprolites. — E. H.] 



My last letter, despatched to you a few days after Mr. Vaill's 

 visit, contained the proofs of the presence of phosphates in your 

 coprolite. I have now the pleasure to add, that uric acid exists 

 in the same beyond all possibility of doubt. I have not come 

 to this conclusion till after a most patient and critical examina- 

 tion of all my former results, on which I grounded my belief of 

 its existence, added to my recent researches on the second parcel 

 you sent, labelled "coprolite, entirely so, from the same speci- 

 men as that which I sent you." What before was highest prob- 

 ability, is now certainty. I had then failed to obtain the pinky 

 color, one, as Liebig well remarks, of the peculiar characteristics 

 of uric acid. 1 had then procured only yellow ; which, I may 

 say, is almost equally characteristic, and is always the conse- 

 quence of too much acid, or too much heat. The quantity of 

 urate I have been obliged to operate upon, at any one time, has 

 been so small, that to produce the pinky color was a matter of 

 no small nicety ; but I have succeeded in so doing several times. 

 In my former trials you may remember, that after treating the 

 coprolite by alcohol and boiling water, I followed with caustic 

 potash, and obtained traces of what I supposed to be uric acid. 

 I find in a second trial, by repeated washing of the mass by wa- 

 ter, that such a result was not obtained. I concluded, therefore, 

 that uric acid existed in a soluble urate, and from other trials, 

 chiefly as urate of ammonia with some lime. It is to be looked 

 for in the alkaline and watery solution of the coprolite. My 

 inquiries were at last directed only to the educts so obtained. 



