314 Scientific Intelligence. [AiPttll> 



with the bulb in the cistern ; I have found that by carrying a barome- 

 ter in my hand and near the bodj r , the temperature is increased consi- 

 derably, and will frequently rise as high as 85° Fahr. _ 



" In the barometer of common construction, the height of the column 

 of mercury is marked offfrom another instrument, presumed as a stand- 

 ard, and in that case, the actual height is rarely or ever given, for 

 every change that takes place in the weight of the atmosphere, alters 

 barometers more or less according to the proportion which the diame- 

 ters of the tubes bear to those of the cisterns, and for that reason, upon 

 examining twenty barometers no two will agree, unless they were 

 marked off together, and happen to stand at that exact height. 



" To remedy this source of error each instrument may be reckoned 

 a standard, the height of the column is marked off from the surface of 

 the mercury, and the point given at which it was marked off; when 

 with the correction for the capacities of the tube and cistern, and also 

 the temperature, the actual height of the barometer is ascertained. 

 Upon examining the first four which I made independent of each other 

 on this principle, one for Mr. Daniell, one for the Royal Society, and 

 two for Capt. Sabine, they agreed within '004 of an inch with each 

 other." — (Institution Journal, xvi. 277.) 



II. Vegetable Alkalies. 



Mr. Brande has lately given analyses of several of these bodies, some 

 of which differ much from those of MM. Dumas and Pelletier, men- 

 tioned in the Annals for Januaiy. The most remarkable discrepance 

 is in the analysis of cinchonia. The mean of Mr. Brande's analyses 

 gives as its constituents 



Carbon 79*30 



Azote 1372 



Hydrogen 7*17 



100-19 



This substance, according to MM. Dumas and Pelletier, contains 

 oxygen, and consists of 



Carbon. . 7(y97 



Azote 9-02 



Hydrogen 6'22 



Oxygen 779 



10000 



The following, Mr. Brande states as an approximation only to the 

 correct proportions of the elements of quina : 



Carbon 7380 



Azote 13-00 



Hydrogen 7-65 



Oxygen 5 55 



100-00 



