2 1 6 Intclltfjrence and Miscellaneous Articles* 



'to 



PoLYB. (Phalcobsenus) albogularis, 



I have some doubts as to whether this bird may not eventually 

 prove to be a variety of Phalcohcenus montana, D'Orb. The prin- 

 cipal difference between this bird and the one described and figured 

 by M. D'Orbigny is, that the throat and chest of the latter are 

 brownish black, while the same parts in this bird are white. 



BuTEO var%us2iXsABut. ventralis; Circus megaspilus and OTUs(Bra- 

 chyotus) galapagoensis. On the last-named bird Mr. Gould observes : 



lliis species belongs to that section of the homed owls which 

 comprehends the short- eared owl of England, and numerous other 

 nearly allied species which are distributed universally over the 

 globe, from all of which it may be distinguished by its smaller size 

 and darker colouring. I am led to regard the members of this sec- 

 tion as possessing characters of sufficient value to justify their being 

 separated into a distinct genus, for which I propose the name of 

 BracUyotus, 



XXXI. Intelligence and Miscellaneous Articles, 



PREPARATION OF PROTOXIDE OF TIN. 



OWING to the great difficulty of preparing protoxide of tin accord- 

 ing to the directions generally given in chemical works, I was led 

 to make some experiments on the subject. I find the following process 

 to be that which yields the purest oxide. Prepare a solution of pro- 

 tochloride of tin by dissolving the metal in hydrochloric acid, taking 

 care always to have a great excess of the metal ; the solution is then 

 evaporated to dryness, together with a lump of tin to prevent the 

 formation of perchloride. The tin is then separated, and the chlo- 

 ride weighed, and rubbed in a mortar with its equivalent, or rather 

 more, of crystallized carbonate of soda ; the mixture soon becomes 

 fluid ; it is then put into an evaporating dish and heated on the sand- 

 bath, frequently stirring, till it becomes thoroughly black ; it is then 

 removed and well washed with boiling water, filtered, and dried at a 

 gentle heat on the sand-bath. The oxide thus prepared is of a beau- 

 tiful blue-black or slate colour ; it is very soluble in hydrochloric 

 acid, and when heated to dull redness in the air, it takes fire and 

 burns, and is converted into peroxide. 



St. Thomas's Hospital, January '3rd, 1838. S. A. Sandall. 



PREPARATION OF BICARBONATE OF POTASH, BY 

 PROF. WCEHLER. 



Carbonate of potash, both in the dry state and in solution, com- 

 bines very slowly with the second equivalent of carbonic acid to form 

 the bicarbonate of potash. By means of charcoal in a finely divided 

 state the combination may be made to take place very easily. It 

 can be performed in the following manner : bitartrate of potash is to 

 be heated in a covered crucible, the burnt mass to be moistened with 

 water, put into a receiver, and carbonic acid passed through it. The 

 absorption takes place with such rapidity that the mass becomes 



