NATURAL PHILOSOPHY. 



ON PHYSICS AS A BRANCH OF THE SCIENCE OF MOTION. 



THE following are the chief points of a paper on the above subject, pre- 

 sented to the British Association, I860, by J. S. Gleniiie: 



The object of the author was not to enter into the full subject, but, by sub- 

 mitting it to discussion, to gain the advantage of criticism. He conceives 

 atoms as mutually determining centres of pressure, that is, more definitely, 

 as centres of lines, the intensity and direction of which are determined by the 

 intensity and direction of the lines from surrounding atoms. Thus, atoms 

 are neither conceived as particles of matter, acted on by extraneous forces 

 of attraction and repulsion, nor as vague centres offeree; and that pressure 

 generally is conceived as measured by M. 0. Motion is not conceived as "a 

 quality of matter, of which no further account can be given," but as the 

 effect in any place of a difference of the polar pressures on a body in that 

 plane. The principle to which the author most constantly has to refer is, 

 that "the motion of a body is in the direction of least resistance; or, motion 

 is the effect of, and proportional to, the difference of polar pressures. From 

 thence, by a train of mixed metaphysical and mathematical conceptions, to 

 deduce that gravity, the law of universal attraction, is the mechanical con- 

 sequence of difference in the masses of a system, mutually connected by 

 their lines of pressures and repelling; and that thus the law of the inverse 

 squares is rather a mathematical than a physical law. 



ON THE NECESSITY FOR INCESSANT RECORDING, AND FOR SI- 

 MULTANEOUS OBSERVATIONS IN DIFFERENT LOCALITIES, TO 

 INVESTIGATE ATMOSPHERIC ELECTRICITY. 



The following is an abstract of a paper on the above subject presented to 

 the British Association, Aberdeen, by Professor W. Thompson : 



The necessity for incessantly recording the electric condition of the atmos- 

 phere was illustrated by reference to observations recently made by the 

 author in the island of Arran, by which it appeared that even under a cloud- 

 less sky, without any sensible wind, the negative electrification of the surface 

 of the earth, always found during severe weather, is constantly varying in 

 degree. He had found it impossible, at any time, to leave the electrometer 

 without losing remarkable features of the phenomenon. Beccaria, Profes- 

 sor of Natural Philosophy in the University of Turin a century ago, used to 



