17G ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



tal. The bars operated upon by him were two inches long, 

 and had a square section of 'about the seventieth part of a 

 square inch. He finds that the amount of deflection in the 

 centre of a bent bar is a function of many quantities, but his 

 observations allow him to state, first, that the deflection of a 

 bar whose section is a perfect square is the same, no matter 

 against which side the bending force is applied. Second, it 

 varies with the dimensions of the bar as regards its thick- 

 ness, breadth, and length, precisely as though the body were 

 homogeneous ; and the same laws apply to it within the lim- 

 its of accuracy of his observations as apply to ordinary iron 

 bars, the deflections being proportional to the cube, to the 

 thickness, and to the length. Third, the deflection is de- 

 pendent in a peculiar manner on the direction of the axis of 

 the bar, in relation to the optical axis of the crystal from 

 which it is cut. There exists, however, in this respect no 

 symmetry with reference to the optical axis of the crystal. 

 Bars cut parallel to the longest diagonal of the crystal give 

 a minimum of deflection ; those cut parallel to the shortest 

 diagonal giving a maximum deflection. Inaugural Diss., 

 Berlin, 1875'. 



A NEW MANOMETER. 



M. Fol has submitted to the Physical Society of Geneva a 

 description of a manometer specially designed for deep-sea 

 soundings. This instrument consists essentially of two spher- 

 ical reservoirs, superposed, and connected by a capillary tube. 

 The upper reservoir should be closed and filled entirely with 

 a compressible liquid for example, alcohol. The other sphere 

 has an opening in its upper part, and is filled with mercury, 

 which also fills the capillary tube. The quantity of mercury 

 which shall have passed from the second reservoir into the 

 first, Avhen the apparatus has been submitted to a given 

 pressure, will give the measure of this pressure, and conse- 

 quently of the height of the column of water or the depth 

 in the sea. Mem. de Soc. d. Phys. de Geneve, 1874, 483. 



THE TIIYSICAL PROPERTIES OF MATTER IN THE LIQUID AND 



GASEOUS STATES. 



Professor Andrews, in a preliminary notice of his research- 

 es on the physical properties of matter in the liquid and gas- 



