Proceedings. 113 



been under examination by him preparatory to being sent 

 to the British Museum. Some of the specimens were 

 unique, and others from parts of the world in which they 

 were, previously to the Challenger expedition, unknown. 

 Three specimens of a genus only known previously on the 

 coast of Greenland were found in different parts of the 

 world, while of a genus only known to live in crannies in 

 rocks, specimens were found in the Pacific Ocean, in deep 

 sea, and of deep-sea characteristics. 



Dr. James Bottomley read the following " Note on 

 the Rate of Dissolution of Solids " : — 



" In a paper read before the Society in February of this 

 year I considered the rate of dissolution of a solid placed in 

 a menstruum capable of dissolving it ; in all the cases con- 

 sidered the rate of action was supposed to be the same along 

 every normal. But we may have to deal with solids in 

 which this latter condition is not fulfilled. Generally the 

 expressions to be integrated will become more complex, but 

 if the solid be bounded by plane faces the investigation will 

 be simplified. For example, suppose we have a parallelo- 

 piped of which the edges at any instant are x, y, z. Then 

 V and S, being volume and surface, we shall have 



V = xyz (1) 



S = 2 (act/ + yz + xz) (2) 



After the lapse of time dt the edges will become x— 2dx, 

 y — 2dy, z—2dz, hence we have 



dv = — 2{xydz + yzdx + xzdy) (3) 



Let m be the ratio of the velocity along the axis of y to 

 that along the axis of x, and n the ratio of the velocity 

 along the axis of z to that along the axis of x, so that we 

 may write 



dy — mdx, dz = ndx. 



Integrating these equations, we get 



y = mx + p z = nx + q 

 H 



