12.0 Mr. henly’s Experiments and 
will fometimes remain in it fo as to confufe and adtualif - 
miflead in the experiments. 4thly, Some minute fub- 
ftances, as a fmall leaf, feed, or hair, will not be eafily 
excited in damp weather; thefe, therefore, as well as the 
apparatus, fhould be warmed; for heat, I find, doth al- 
ways difpofe bodies to become eledtrical. 5thly, The in- 
fulating Hands, and the flicks of fealing-wax, with which 
the fubftances to be examined are connected, fliould not 
be rubbed, left they, by the fridtion, fliould be made 
eledtrical, and, adting through the fubftance in contadl 
with them, deceive in the experiment. Gthly, The ani- 
mal fubftances, as hair; horn, bone, cartilage, nails, teeth, 
mufcles, See. become eledtrified pofitively, by friction, 
againft woollen cloth or black filk; and the. vegetable 
creation, with very few exceptions, negatively. The metals 
differ with refpedt to kinds, form, and furface, and may be 
differently affedted by different rubbers. Laftly, I muft 
not omit to obferve that, among vegetables, I find the hot, 
acrid, pungent,,and aromatic fubftances, as the fpices,8ec. to 
be much more eafily excited, and ftronger in their power, 
than the cold ones, as the feeds of gourd, melon, or cu- 
cumber. Among the herbs, hemlock and parfley are 
ftrong : a Angle leaf of laurel, bay, yew, rofemary, See. 
will be found very powerful; but, as I have before ob- 
ilwvcd, this field is indeed immenfe, and life itfelf too. 
fhort 
