C. GENERAL PHYSICS. 143 



the uniform consumption of a volatile organic substance of 

 unvarying composition. A metal flask, such as is used in the 

 liquefaction of carbonic acid by batterer's apparatus, is par- 

 tially tilled with ether, and immersed in a tin vessel filled 

 with water. The exit tube is supplied with a burner at the 

 end, and a small water manometer on the side, intended to in- 

 dicate the pressure under which the vapor reaches the burner. 

 When the water is raised to 212, if the quantity of ether 

 present is suflicient, the vapor will be delivered to the burner 

 under a constant pressure for hours, and afford a beautiful, 

 quiet, white flame, approximating that of gas. In practice, 

 an apparatus weighing no more than 1500 to 2000 grains 

 could be made to resist more than double the low pressure 

 of the vapor, and the consumption for a given time could be 

 accurately determined to 0.015 of a grain; while by stating 

 the size of the opening of the burner, the material of which 

 it is composed, and the height of the flame, a flame of equal 

 intensity, consumption, etc., could easily be reproduced and 

 regulated. It is also suggested that such an instrument 

 might answer for the determination of the quality and ex- 

 plosiveness of petroleum, and several such are being construct- 

 ed adapted to various uses. 13 (7, March, 1874, 307. 



THE FLUORESCENCE OF AMBER. 



Dr. Labert, of Breslau, states that he lately received a col- 

 lection of beautiful pieces of amber from Sicily, and, on com- 

 parison with the amber from the Baltic, was struck with the 

 great difference of color, and especially the frequency of con- 

 trasts between the surface and the inner color of the pieces. 

 Following in the track of Brewster, Ilerschel, and Stokes, Dr. 

 Labert applied the proper tests to his amber, and easily de- 

 termined that both the Sicilian and the Baltic specimens no- 

 tably exhibited the well-known phenomena of fluorescence. 

 Two pieces of amber, which on the surface exhibited a beau- 

 tiful blue color, showed a yellowish red color when viewed 

 from the side ; but the phenomena seemed to be subject to 

 slight variations in each separate piece of amber. The fluo- 

 rescence was much more decided in the Sicilian specimens than 

 in those from the Baltic. He suggests, in connection with 

 this subject, that it is well worthy of consideration whether, 

 in the neighborhood of Sicilv, there be not a sunken centre 



