L 



W. /. Taylor on Rock Guano. 183 



of tlie magnesia, tLere remains 8'75 oxygen of lime, which is to 

 the oxygen of phosphoric acid 23'25, about in the ratio of 1 : 2, 

 particularly as the oxygen of the alumina requires oxygen of 

 the phosphoric acid, to form a salt with a formula most probably 

 corresponding to that of wavellite as before mentioned. 



Mr. Richards brought with him also a specimen of the recent 

 alluvial guano or bird excrement, as it may bo justly termed; 

 he obtained it from a little nook in the rocks, where it was pro- 

 tected from the intense dry heat of the sun and from the action 

 of water. Mixed through it were several birds feathers. As 

 niay readily be imagined, it had some odor, though not exces- 

 sively strong. 



7'4921 grams, were ignited in a platinum crucible, and gave 

 a very strong and disagreeable odor like burning hair; it was 

 moistened with carbonate of ammonia and again gently heated, 

 and gave a loss of 4*0032 grams- = 53 '83 per cent. 



(IX.) 



2-19'75 grams; of tlie asli showed a trace of alumina. 



" « 0-2746 grams. BaO, SOs gave siilpliuric acid, 4-29 



2-236 « 1-5150 " CaO,C02 « lime, 38-02 



" " 0-0913 « sand « 4-83 



4-0704 « ignited gave a loss 1-9171 gram. 47-10 

 1-9997 " ash 



U 



U 



1-3858 grams. CaO, CO2 gave lime, 38-89 



** 0-2206 " BaO,S03 " sulphuric acid, 3'79 



" « 0-2100 " • 2MgO,P05 « magnesia, 3-77 



" 1-3178 " 2MgO,P05 " phosphoric acid, 42-21 



" " 0-0225 " " sand " 3-25 



" " 0-0164 *' Ag " chlorine, 0-26 



3-9652 « loss by ignition 1-9282 gram. 48-62 



•9857 « 0-6892 grams, CaO. Cos gave lime, 89-12 



•9794 " 0-0085 " CO2 " carhonic acid, 0-86 



" " 0-1250 " BaO, SOs " sulphuric, 4-28 



Lime, 38-89 per cent. Oxygen ratio, 11-05 



Phosphoric acid, 42-21 " « " « 23-65 



Sulphuric acid, 4-29 " « " " 2-57 



Magnesia, 3-77 " « « " TSO 



2 57 oxygen in sulplmric acid require 0-85 oxygen in lime ; 

 there remains 10-19 oxygen of lime, which, if added to the oxy- 

 gen of the magnesia makes 11-69, which stands with the oxygen 

 of the phosphoric acid 23-65, near the ratio 2CaO, PO5. 



A guano rock has recently been brought from a group of 

 islands called El Roque, in the Caribbean Sea. In composition 

 it resembles very closely that brought from Monk's Island ; the 

 specimens that I have analyzed, contain however, a much larger 

 quantity of sulphuric acid than has been found in the latter rock. 



