48 Analysis of the Coprolites of Birds. 



9. The precipitate (6) solves in part in acetic acid, but a por- 

 tion, say one third, remains unsolved even in boiling acetic acid 

 — is therefore phosphate of lime. 



(This yon know is now the favorite mode of Daubeny, John- 

 ston, and others, of detecting phosphates in soils. I tried it be- 

 cause it was ready and easy. Let it go for what it is worth.) 



Page 42. — 12. The water solution by muriate of barytes 

 shows slight traces of sulphuric acid. 



Sept. 8. — 1st. 3 grains heated to redness. 



2. This solves with brisk effervescence in nitric acid, and 

 leaves unsolved dark brick red ashes. The nitric solution be- 

 ing treated with nitrate of silver, no cloudiness occurs ; but on. 

 neutralizing the acid, an abundant yellow precipitate occurs. 

 Hence phosphoric acid unequivocally. 



Sept. 9. — The solution of mixed nitrates and phosphates was 

 treated by acetate of lead. Copious precipitate of phosphate of 

 lead occurred. 



Had this been due to any sulphates, (I allow it may have been 

 in part, but then the traces of sulphates should have been vastly 

 greater,) it is to be recollected that heat and carbonaceous mat- 

 ter would destroy sulphuric acid. 



Sept. 10. — A few grains of the substance boiled in dilute 

 caustic potash. 



Sept. 11. — On the addition of the caustic potash to the above 

 powder in boiling, distinct clouds with muriatic acid were ob- 

 tained. Ammonia. 



I do not think it worth while here to extend my experiments 

 with the watery solution of nitrate of silver. They show cer- 

 tainly organic matter. 



[An additional quantity of coprolite was forwarded to Dr. 

 Dana, which he acknowledges in the following letter of Novem- 

 ber 19, 1843, with an account of farther experiments upon the 

 portion previously sent. — E. H.] 



I received the parcel of coprolite by Mr. Vaill. I am now at 

 work upon it. Before he arrived I began with what of the old 

 stock remained. I found a small portion in one of my test 

 tubes, which had been treated only by alcohol and water. Let 

 us call this No. 1. No. 2, the remains of that treated with caus- 

 tic potash for uric acid, &lc. No. 3, the precipitated phosphate 

 of silver. No. 4, the phosphate of lead obtained in my analysis. 



