30 Sketch of the Improvements in Science [Jan. 



2. Oryctognosy . 



The additions to tliis branch of mineralogy, as far as they have 

 come under my knowledge, have not been very numerous. ■ 



1 . The description of a collection of minerals from Greenland, 

 by Mr. Allan, published in the second Nimiber of the Annals of 

 Philosophy, together with the sketch of the constitution of Green- 

 land written by the same gentleman, and published in the 1 1th 

 Number, would be read with interest by all mineralogists. 



2. The mineral called lythrodes by Karsten will be found de- 

 scribed in the second Number of the Annals. I am not aware that 

 any specimens of it have been brought to this country. 



3. Subsulphate of alumina has been found on the south coast of 

 England, first by Mr. Webster, and afterwards by Mr. Smithson 

 Tennant. It is a beautiful white mineral, bearing a certain re- 

 semblance to porcelain clay. 



4. The turquois has been ascertained to be a peculiar species of 

 mineral, and not fossil bone coloured green, as has been supposed 

 by some. 



5. Chromium has been found in chlorite and in serpentine. 



6. Titanium has been found by Schrader in graphite. 



7. Mr. Holme has analysed arragonite, and found it to contain 

 a portion of water, which does not exist in calcareous spar. In 

 Germany the presence of strontian has been announced in this 

 mineral. 



8. The resin found while digging the Highgate Archway appears 

 from my analysis to differ from all other resinous bodies at present 

 known. 



y. For the properties and constituents of pyrodmalite, I refer to 

 the last Number of the Annals. 



10. Daubuisson's discovery of the hydrous carbonates of iron, 

 and his new arrangement of the ores of that metal, in consequence 

 of this discovery, is an improvement of some value in this difficult 

 part of oryctognosy. 



X. Meteorology. 



The year 1812 was uncommonly cold. Its mean temperature in 

 London was 49-2'^; and the mean temperature of July, the hottest 

 month, was only 61-3°. The mean temperature of December, the 

 coldest month, was 3fJ-5°. The mean height of the barometer in 

 London, at the height of 81 feet above the river, was 29-79 inches. 

 If we suppose that the mean height of the barometer at the sea 

 shore is 30 inches, this would indicate the height of the surface of 

 the Thames at Somerset-house above the sea about 81 feet, which 

 I conceive is greatly beyond the truth. Col. Mudge, in his survey, 

 if 1 recollect right, reckons it only 7 feet above the Nore. From 

 this it seems to follow as a consequence that the mean height of the 

 barometer at the sea shore is only 29-9 inches. 



