212 ANNUAL KECOKD OF SCIENCE AND INDUSTRY. 



thus supplying light and mechanical power as well as the 

 water. 



Wild has communicated to the St. Petersburg Academy 

 of Sciences an important metrological paper, in which he de- 

 scribes his new linear comparator, and gives the results of 

 his examination with it of a normal meter made by Hermann 

 & Pfister, of 13erne. The new comparator reads to 0.0001 

 millimeter and to 0.01 of a degree Centigrade. The true 

 length of the normal meter was found to be 999.9838 millim- 

 eters, with a probable error of 0.00026 millimeter. Wild 

 also discusses the desirability of quartz in the form of rock- 

 crystal as a material for standards, especially for linear units, 

 and gives his opinion strongly in its favor. A spherical or 

 cylindrical standard hectogram of this material, or a stand- 

 ard divided decimeter, can now be had of Stein, in Oberstein, 

 for thirty thalers. A simple and excellent method of read- 

 ing the deflection in balances of great precision, by means 

 of a mirror with its telescope and scale, placed at a distance, 

 is also given. 



The mathematical treatment of the problems arising from 

 the motions of bodies confined to the surface of the rotating; 

 earth has been treated of by Bertram in an inaugural disser- 

 tation at Marburg, on the motion of a material point upon 

 surfaces of rotation ; and by Suttor, of the Royal Institute 

 at Luxembourg, on the movement of bodies on the surface 

 of the earth, etc. The former author confines himself to the 

 elaboration of very general mathematical formulae for rota- 

 ting cylinders, paraboloids, spheres, etc. The latter author 

 gives more special formula?, deduced from Corioli's proposi- 

 tions, and shows their adaptation especially to the vibration 

 of pendulums, and the experiments of Foucault on the roll- 

 ing of spheres down inclined planes, and the fall of bodies, as 

 in Reich's experiments at Freyberg. 



Jewell has described in Nature a new form of sinker for 

 deep-sea sounding, in which certain objections to the sinker 

 of Sir William Thomson are obviated. An iron casting live 

 inches in diameter at the top and three at the bottom, and 

 20. 5 inches long, is cast with a cylindrical cavity two inches 

 in diameter, extending from the top to within an inch of the 

 base. A glass tube forty-eight inches long is closed at one 

 end and bent so as to produce a U tube twenty-four inches 



