306 LITERARY NOTICES. 



mode of treating this difficult subject. Professor Phillips read a report of 

 experiments made for the purpose of determining the inferior temperature of 

 the earth, and, in connection with this subject. Prof. Forbes gave an extempor- 

 aneous account of some experiments in the mines on the Lead Hills. These 

 were followed by a paper of Mr. Craig's on polarized light, who in the course 

 of his remarks detailed the five ordinary methods of polarizing light: 1. Byre- 

 flections at certain angles from plates of glass. 2. By reflections from similar 

 plates, having their under surfaces blackened, so as to absorb the rays upon 

 their coming to the back surface of the glass, and to this glass he would refer 

 the effects of all polished surfaces, such as varnished mahogany tables and trays, 

 japanned metals, burnished leather, &c., and he instanced the total disappear- 

 ance of all diversity of colour from varnished card of several colours, when 

 viewed under certain circumstances, through eye-pieces of tourmaline, Iceland 

 spar, &c. 3. By transmitting the ray through certain crystalline substances, 

 such as Iceland spar, &c. 4. By passing the ray through crystals of tourma- 

 line cut by planes parallel to the axes of the crystal. 5. By the use of Nicholl's 

 double fusion of Iceland spar. The rev. gentleman then proceeded to explain, 

 in connection with his theoretic views, the play of colours observed within 

 certain kinds of crystals of Iceland spar, the distinction between right-handed 

 and left-handed quartz crystals, and numerous other instances derived from 

 facts familiar to those who have studied this branch of science. 



Mr. Russell gave an account of researches regarding the laws of the motion 

 of waves, a subject deserving the greatest attention, especially when taken in 

 connection with the investigations of Messrs. Whewell and Lubbock on the 

 tides. Mr. Russell divides waves into four classes, to the two latter of 

 which his enquiries were chiefly confined : 1. Waves of the first species are 

 seen in what is commonly called ripple on the surface of a pool ; these may 

 be called dentated, and are not propagated beyond the place of their genera- 

 tion. 2. Waves of the second species, or oscillatory waves, are found when a 

 stone is dropped into a quiescent fluid, and these succeed each other in con- 

 centric rings these are the waves of Newton and Young, and correspond to 

 the second species of poisson ; they are propagated with a velocity propor- 

 tioned to the magnitude of the displaced fluid. 3. The third species of waves 

 are called breakers, surges, and tidal-bores ; and, 4. The fourth species of 

 waves is the solitary wave, analogous to the great tidal- wave of the ocean ; 

 it is propagated with nearly a uniform velocity. The following principles 

 may be considered as ascertained. The two last species, the surge and the 

 solitary wave, are the subjects of this investigation. It was observed, 1st, 

 When a considerable and permanent addition is made to the volume of a 

 limited portion of fluid contained in an open reservoir, such addition pro- 

 duces an elevation of the surface of the fluid, which is propagated in the 

 form of a solitary wave, moving with a velocity nearly uniform. 2nd, The 

 velocity of the propagation of such waves is equal to that which would be 

 acquired by a heavy body, in falling through a space equal to half the depth 

 of the fluid. 3d, The length of such a wave is nearly constant for a given 

 depth. 4th, The height of the wave varies with its volume, and must be 

 added to the depth of the fluid, in calculating the velocity according to art. 

 5th, When the height of a wave exceeds twice the depth its form ceases to 

 be a form of equilibrium, and it breaks. 6th, When the anterior part of a 

 wave is found at a depth less than that of the posterior portion, and the 

 height is greater than twice the depth, the wave curls forward, forming the 

 common surge. 7th, When the width of a channel diminishes in an arith- 

 metical ratio, the height of the wave increases in a geometrical one until it 

 exceeds twice the depth, when it breaks. 



Mr. Russell received some very handsome compliments from Mr. Scoresby, 

 Mr. Whewell, and Sir William Hamilton. Besides the papers above men- 

 tioned, must be enumerated Professor Powell's paper on the degrees of 

 refraction of different transparent substances, Mr. M'Gauley's account of 

 experiments in electro-magnetism with reference to its application as a 



