Wakelin. — On Gravitational Experiments. 409 



last few weeks, when I saw the following account: — " The quality I refer to 

 is ' electric conductivity,' and the result of that quality in the experiment I 

 am now going to describe is, that a piece of copper, or a piece of silver, let 

 fall between the poles of a magnet, will fall down slowly, as if it were falling 

 through mud. I take this body and let it fall, many of you here will be 

 able to calculate what fraction of a second it takes to fall one foot. If I 

 took this piece of copper, placed it just above the space between the poles of 

 a powerful electro-magnet and let it go, you would see it fall slowly down 

 before you ; it would perhaps take a quarter of a minute to fall a few 

 inches."* 



Professor Tyndall in one of his works speaking of this condensation 

 between the poles of powerful magnets says that it takes as much exercize 

 of force to make a knife go through this magnetic matter as it would take 

 to cut a piece of cheese. My memory may be at fault here, but I am 

 certain that he spoke of the resistance as something wonderful. Now this 

 magnetic matter may displace a gravitational medium, or it may be con- 

 nected with it in a way so as to weaken it. It seems to me, if one me- 

 dium produces both electrical and gravitational effects, that if one effect 

 is disturbed, the other must be disturbed also. Let us suppose the above 

 experiment to be repeated with this modification. To the piece of silver 

 placed between the poles, let another piece exactly equal be fastened by a 

 wire long enough to let the second piece hang so far below as to be alto- 

 gether out of reach of the influence of the electro-magnet; there is a 

 resistance to motion of the piece of silver due to the thickness of magnetic 

 matter. If the weight-giving force act equally on the two pieces of silver, 

 the force overcoming the magnetic matter being doubled, the pieces of 

 metal will fall about twice as fast as in the original experiment. If, how- 

 ever, the bodies are made to fall by some physical agent, then, if the 

 magnetic matter displaces this agent, or modifies its gravitational action 

 in the piece of metal between the two poles, the addition of the lower 

 piece of silver has more than doubled the force, and the pieces of silver fall 

 more than twice as fast. And if the experiment was tried, and this was 

 found to be the case, we should reasonably infer that gravitation was pro- 

 duced by some physical agent. 



Fourth Experiment, Electrical. — The electric medium is believed to be 

 continuous, just as the luminiferous ether is believed to be continuous. 

 " We may say that all electric forces are transmitted by strains of the ether, 

 but that the ether in different insulators is modified in some way which 

 will account for the difference of transmission."! I suppose an electric 



* From Sir W. Thomson's "Lecture on the Senses," published in "Nature," 6th 

 March, 1884. 



t A Physical Treatise on Electricity and Magnetism, by Gordon, p. 22. 



