[ 7 ” 1 
1 6. I have tried the EfFed of increafing the Quan- 
tity of Water in the Glafles of .different Sizes, as 
high four Gallons, without in the leaft increafing 
the* Stroke. If * Filings of Iron are fubftituted in the 
Room of Water, the Effed is confiderably leffenM. 
If Mercury, much the fame as Water; the Stroke 
is by no means increafed in proportion to their fpe~ 
cific Gravities, as might have been imagined §. 
1 7. The Phial fhould not be lefs than can con- 
veniently be grafped. I generally make ufe of 
thofe, which hold feven or eight Ounces, and fill 
them about four Fifths with W ater j and the Stroke 
from one of thefe, under the fame Circumftances, is 
equally ftrong with that of a Florence Flask held in 
the Hand, which I have fometimes made ufe of ; 
though the Glafs of this laft is equally thin with that 
of the Phial, and the Quantity of Water four times 
as much. That the Stroke therefore is not as the 
Quantity of Water electrified, is evident from this 
Experiment. This Fact does not depend upon my 
Judgment alone, but likewife upon the Opinions of 
feveral learned Members of this Society , who have 
experienced the greater and lefs Quantity of Water. 
18. If a dry Twig of Birch, or any other Wood, 
be run through the Cork inftead of the metallic 
Wire, 
* For a farther Account of the Filings of Iron, made ufe of in this Ex- 
periment, fee thefe Travfattions, Vol. XLV. p. 107, 
§ In this Experiment, and in others, wherein we affert, that the 
Stroke is not increafed in proportion to the Quantity of eledtrified Mat- 
ter ; it muff always be underitood, that the excited Non-eledlrics them- 
felves are touched, without being contained in Originally-eledlrics, as 
Water in the Glafs; for otherwife (as will hereafter be fpecified) the 
Effe&s of different Quantities of Matter will be very different. 
Zzzz 
