ELECTRIC COLUMN. 
307 
a/1 produced at the same time by a given quantity of moving gf 
force ; and it is certainly a desirable object to determine what c’ byiii the 
i- 1 ■ 1 . 11 - 1 1 -di.ctriiifs of 
portion of that quantity has been expended in producing each of moving force, 
these different effects. 1 have endeavoured to show that all 
these changes may be distinctly explained and estimated, by 
examining the pressure and the space through which it acts in 
producing them. 
In objecting to the opinions of many eminent writers on 
mechanics, I have ventured much. Although this has not been 
done inconsiderately, I am sensible there aftj in the arrangement 
of my arguments some faults, and others which have escaped 
ray observation, will no doubt occur to the reader. But if ray 
endeavours to make this essay more free from imperfections 
than it is, had been successful, it would still be unreasonable to 
expect it to obtain more attention than has been paid to the 
arguments of the illustrious men who have preceded me in the 
same track of investigation. If I have succeeded so far only as 
to show, that the prevailing doctrines of force, especially in 
their application to practical purposes, involve some dithculties 
which are unexplained j and if I have offered any inducement 
to men of science to re-examine this question, my chief object 
will in a great measure be accomplished. 
II. 
On a new phenomenon of the Electric Column, produced ly the 
Sun-rays, 
To JVilliam Nicholson, Esq. 
JFhidsor, Nov. 8, 1813^ 
SIR, 
S INCE the date of ray paper published in your number of 
the 1st of October, I have found a new and interesting 
phenomenon produced in the electric column, by the sun’s rays 
Z 2 falling 
