Intelligence and Miscellaneous Articles. 393 



extent broken up into detached propositions, yet he states that in his 

 opinion "this is not the form in which such a treatise ought to be 

 written " (pp. vi, vii). And with reference to the chapter of 

 " General Theorems," he says that several of the results proved in 

 it " have already occurred as immediate deductions from the laws 

 of motion ; but to maintain the special character of the work we 

 give more formal analytical demonstrations, though these are cer- 

 tainly superfluous ''* (p. 259). We cannot help thinking that the 

 unintelligible examples should have been omitted, and that the book 

 should have been written in the form that seemed best to the writer. 

 But if this could not be, and he were in any sense writing to order 

 and so obliged to compromise, surely it is somewhat ungracious to 

 proclaim his dissent, from what is after all his own act and deed, 

 upon the house-tops. The fact is, if we may venture to hint at a 

 fault, the Professor's individuality is a little too pronounced. If he 

 thought it best, on the whole, not to act upon his private opinion, 

 it would have been better to have kept silence. Occasionally the 

 fault takes another form, and he indulges in some thing that might 

 almost be called autobiography. A very curious instance of this is 

 to be found in the confession that, when he wrote the second 

 chapter as it stood in the First Edition, he had not so much as read 

 "Newton's admirable introduction to the Principia." 



LII. Intelligence and Miscellaneous Articles. 



A CONSIDERATION REGARDING THE PROPER MOTION OF THE SUN 

 IN SPACE. BY S. TOLVER PRESTON. 



TT is a known fact that a wave emitted in a medium does not 

 4- partake of the motion of the body emitting it ; for when once 

 the wave has left the body, the wave depends solely on the medium 

 for its propagation. Hence it would follow that, owing to the 

 sun's proper motion in space, the waves emitted by the sun must 

 be situated eccentrically about it, the degree of excentricity marking 

 exactly the direction and velocity of the sun's proper motion in 

 space (or in the aether which fills all space). It thereby becomes 

 possible (in imagination at least) to refer the proper motions of the 

 sun and stars to one common standard, viz. to the universally dif- 

 fused aether : or it may be said that the direction and velocity of 

 the sun's proper motion (and that of every star) is physically 

 marked in the aether of space — each stellar sun marking the direc- 

 tion and velocity of its motion with geometrical accuracy by means 

 of the relative situation to one another of the spherical waves suc- 

 cessively emitted, each of which remains immovable or unalterable 

 in position (in regard to its own centre). In short the centre of a 

 spherical wave may be said to represent indestructible position, in 

 the sense that the centre of the spherical wave is an immovably 

 fixed point, such that the intersection of the normals to two tangent 

 planes situated anywhere on the contour of the spherical wave 



