[ 395 ] 
conceive, that the acid Steams of the Sulphur, 
burnt under the extended Flanel in the Time of 
bleaching, may unite themfelves with the Oil (with 
which Hair, as well as Horns, are found by Analyfis 
to be replete), and form an animal Sulphur, which, 
upon Fri&ion, Vibration, or any nimble Agitation 
of thefe Hairs, may become luminous. 
And that fomething like this may be in the Cafe 
feems not improbable ; fince it hath been obferved, 
that this Appearance hath happened mod confpicu- 
ous in frofly Weather ; in which Seafon there is 
generally not only a greater Purity of the Air, and 
Abfence of Moifture ; but all hairy and horny Sub- 
ftances (and Hairs you know are but fmall Horns) 
are more elaftic, and confequently fufceptible of, 
and capable of exciting, the ftrongcfl Vibrations. 
And, on the contrary, the lixivial Salts ufed in 
wafhing may deftroy the fulphureous Acid, and dis- 
charge the Oil 5 whence the Hairs will become 
more flexible and limber, and be rendered lefs fit 
for exciting the ele&rical Fire. And the fame may 
happen when Flanel is much worn, and by that 
means filled with the alcaline Effluvia s, which go 
off from mod (of the higher Order of) Animals 
by Tranfpiration j which may difiolve the animal 
Sulphur, weaken the Spring of the Hairs, and fo 
render the Phenomenon more difficult. 1 am, 
My good Friend , 
Moji fincerely yours, 
, . Bcnj. Cooke. 
If. 
