GRAY'S EXPERIMENTS. 473 



pieces of foil fly as readily to the cork in the end of the 

 tube as to the tube itself and thus it was plain that the 

 virtue had instantly passed from glass to cork. 



He at once attacks the second part of his problem: 

 how far will this virtue travel? Into the cork in the 

 glass tube he inserts a wooden rod four inches long, hav- 

 ing an ivory ball which he "happened to have by him " 

 at its end. The ball attracts brass foil when the tube 

 is rubbed. Gradually he increases the length of the rod, 

 then substitutes for it a wire until the sagging of the 

 latter makes it troublesome to handle, and then he hangs 

 the ball from the tube by a long piece of hemp thread. 

 Still no change in the attractive power, despite the dis- 

 tance between ball and tube. 



All this is so far beyond his expectations that it seems 

 to him that the effect must in some measure depend upon 

 the nature of the ivory ball; so he takes it off and substi- 

 tutes other objects. He has no store of rare chemicals to 

 draw upon; but the street and courtyard yield him bits of 

 brick and stone and tiles and chalk; and the garden, dif- 

 ferent vegetables and plants; and his purse a gold guinea, 

 a silver shilling and a copper halfpenny. After he has 

 tried all these things always with the same result he 

 looks about his chamber and finds the fire shovel, and the 

 tongs and the poker, and the tea-kettle (which works just 

 the same whether full of water or empty), and his silver 

 pint-pot. By this time he considers the question suffi- 

 ciently settled, and gets out his fishing-rod to see if the 

 virtue will go over even so long an object as that. But it 

 does and over other rods fastened thereto; and how much 

 further it might travel he cannot tell, because his little 

 chamber is not large enough to let him use a series of rods 

 over eighteen feet in length. 



The month of May, 1729, has now come, and Gray is 

 glad to exchange the bricks and mortar of London for the 

 country fields. His "honored friend, John Godfrey, 

 Esq.," of Norton Court, near Faversham, Kent, has in- 



