368 
INDEX. 
Ross (Capt. Sir J. C.). On the Effect of the Pressure of the Atmosphere on the Mean Level of 
the Ocean, 285. 
Rotatory motion , equations of, 105. 
S. 
Solar rays , reciprocal action of, 11 ; vis viva, different phenomena and definition of, 12; greatest 
in the incident wave, 18; equations for the determination of, 15; statical equivalent of re- 
flected and refracted rays, 18 ; demonstration that transmitted solar rays are accompanied by 
a diminution of the refractive index, 25 ; effect of absorption antagonistic to chromatic disper- 
sion, 32 ; explanation of rotatory phenomena of polarization, 35. 
Spermatozoon, method for observing its penetration of ovum, 230; proofs of penetration, 232 ; 
influence of, in the direction of the primary yelk-cleft, 242. 
Square numbers , certain properties of, 311. 
Steam, saturated, on the density of, 344. 
T. 
Thermo-dynamic engines, theory and efficiency'of, 137 ; efficiency between given limits of actual 
heat, 139; of the use of the economiser or regenerator, 140; advantage of a regenerator, 143; 
of temperature, and mechanical hypothesis of molecular vortices, 146; relation between tem- 
perature and actual heat, 147 ; numerical computation of efficiency, 149 ; a heterogeneous 
mass or aggregate in vapour-engines, 154; absolute maximum efficiency of vapour-engines, 
163. 
Toluyl-urea, 48. 
Tyndall (J.). On the Vibrations and Tones produced by the Contact of Bodies having 
different Temperatures, 1; different views concerning, 2; the rocker, 3 ; tones from sub- 
stances of the same nature, 4, 5 ; from the contact of metallic with non-metallic, 7 ; not 
dependent on conducting power, 9. 
U. 
Urine, indigo in, 297. 
V. 
Vibrations and tones, how produced in metals and other substances, 2. 
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