fluid conductors when transmitting the electric current 185 
motion of a molecule from one end to the other of this transfer, 
the intensity of gravity being taken at unity, that of the force 
accelerating each particle of the alloy would amount to 
1 mch — — L— = 0.00521, and each particle of zinc 
being loaded with 100,000 times its weight of inert matter, 
the intensity of the force, acting on its molecules, cannot pos- 
sibly be so little as 521 times their gravity. But it is in all 
probability immensely greater. So far from being uniformly 
accelerated along their whole course, the molecules, if nar- 
rowly watched, will be evidently seen to move with less and 
less velocity as they recede from their point of radiation ; and 
it is assuming little to suppose their velocity at a hundredth 
of an inch from this point double of their mean velocity with 
which they traverse the diameter. To produce this effect, the 
force must ( if supposed to act uniformly through this small 
space) be increased 100 fold, or to an intensity upwards of 
50,000 times that of gravity. Such considerations tend, if I 
mistake not, greatly to enlarge our views of nature, and to 
prepare us for the admission of the most extravagant numeri- 
cal conclusions respecting bodies less within the reach of our 
senses. That such minute proportions of extraneous matter 
should be found capable of communicating sensible mecha- 
nical motions, and properties of a definite character, to the 
body they are mixed with, is perhaps the most extraordinary 
fact that has yet appeared in chemistry. When we see ener- 
gies so intense exerted by the ordinary forms of matter, we 
may very reasonably ask, what evidence we have for the 
imponderability of any of those powerful agents to which so 
large a part of the activity of material bodies seems to be 
owing ? 
MDCCCXXIV. B b 
