UPON GASES AND LIQUIDS. 573 



grooves uppermost ; and the latter, one of which formed the con- 

 tinuation of the other, were covered with a thin lamina of mica 

 at the spot where they are most approximated, forming a bridge 

 from one half of the keeper to the other. When water, which 

 is by no means one of the most strongly diamagnetic liquids, 

 was then placed upon the lamina of mica, and walled in on both 

 sides at some distance from the centre by wax, on looking be- 

 tween the two keepers, the water existing there was seen de- 

 pressed from 5 to 6 millims. towards the lamina of mica, so as 

 to enter the two grooves on opposite sides. Magnetic liquids, 

 on the contrary, moved towards the centre, and there became 

 raised up upon the lamina of mica. 



48. On the other hand, the two parallelopipedal halves of the 

 keeper (A) were laid flat upon the magnet, and placed at a 

 distance of 8 millims. apart, in which position they were fixed. 

 A parallelopipedal box, made of thin sheet brass open above, the 

 longest sides of which were of about the same dimensions as the 

 surfaces of the poles, was placed between the latter, and being 

 about 7 millims. wide, a small space was left for its play. A 

 long glass tube of about 1*5 millim. internal diameter, which 

 slowly ascended in the equatorial plane, was cemented water- 

 tight into the under part of one of the two narrow sides. When 

 a diamagnetic fluid was then placed in the box in such a quan- 

 tity that about a third of it was filled and at the same time 

 the liquid in the tube rose to about its middle, on closing 

 the circuit of a battery of from six to eight Grove's cells, the 

 fluid column, in the case of water, solution of ferrocyanide of 

 potassium, and alcohol, rose from 1 to 3 millims. The reverse 

 occurred on using a magnetic fluid ; a saturated aqueous solution 

 of protosulphate of iron receded in the glass tube more than 

 80 millims. ti hluoir 



I shall reserve for a future communication the investigation 

 of the question, how far the idea of an accurate comparative 

 method of determining the intensity of the magnetism and 

 diamagnetism of liquids may be derived from the preceding 

 experiments, at present confining myself to the phaenomenon 

 alone. 



49. In the consideration of the motion of the liquids, the idea 

 of observing also the motion of the finely divided solid matters 

 mixed with them was of importance, and especially occurred in 

 the examination of the blood. Faraday has already ascertained 



