Remarks on Falco cyaneus, &c. 315 



Coke, or oxide of carbon, obtained from hard coal, is ge- 

 nerally combined with a pure white ash, and frequently pos- 

 sessed of considerable density. The quantity of this alloy 

 may be estimated from the following results from 100 parts 

 of each : 



1st specimen of cokes contained of ashes 6'78 



2d - — 8-25 



3d — * ■ 7'50 



4lh -• ■ 9'54 



5th . — 11*78 



6th - 12-12 



That particular variety of coal, which has been described 

 as belonging to the hard coal class, under the name of 

 stony hard, after combustion leaves a white stone covered 

 with very fine white ashes of the same colour. In many 

 cases the proportion that the alloy bears to the carbonaceous 

 matter is equal, and sometimes greater.— One hundred parts 

 of cokes — 



1st specimen contained of ashes 15*75 



2d — — * 19-50 



3d 28-07 



4th ■ 30'54 



5th — : 1 47*30 



6th — 51-90 



Besides these experiments relative to coals and cokes pro~ 

 duced from wood and pit-coal, I have performed a number 

 of others upon various substances, animal and vegetable, 

 with a view to produce oxide of carbon, to form a genera! 

 estimate of their comparative merits. Some of these I shall 

 fend you for a future number of the Philosophical Magazine. 



XLVII. Some interesting Additions to the Natural His- 

 tory of Falco cyaveus and pygargus, together ■■with He-, 

 marks on some other British Birds. By George Mom* 

 Tagu, Esq. F.L.S.* 



Falco cyan bus. 



Ind. Orn: i. p. 39. 94. 



Hen Harrier. Lath, Syn, 



J. hat the natural history of a bird indigenous to this coun- 

 try, and by no means uncommon, should have so long conr 

 * From the Transactions of theLinnccan Society, voLix, 



tihuedj 



