176 PHILOSOPHICAL TRANSACTIONS. [aNNO 1787. 



of an approaching cloud has been sensible without a kite, though in a very un- 

 favourable situation for it, being in a town surrounded with hills, and where 

 buildings encompassed the wall on which the electrometer was placed. A thun- 

 der cloud passing over, caused the leaf gold to strike the sides of the glass very 

 quick at each flash of lightning. No sensible electricity is produced by blowing 

 pure air, projecting water, by smoke, flame, or explosions of gunpowder. The 

 quantity of electricity necessary to cause a repulsion of the leaf gold is so small, 

 that the sharpest point or edges do not draw it off without touching : hence it is 

 unnecessary to avoid points or edges in the construction of this instrument. 



V. Appendix to the Description of a Neiv Electrometer, By the Rev. Abraham 



Bennet, M. A, p. 32. 



This is a somewhat more particular account of the description of Mr. Ben- 

 net's electrometer ; which however, with an account of experiments, may be 

 profitably consulted in the author's " New Experiments on Electricity," printed 

 at Derby, in 8vo. 1789. 



To the experiments on blowing powders from a pair of bellows Mr. B. adds, 

 that if the powder is blown at about the distance of 3 inches on a plate which is 

 moistened or oiled, its electricity is contrary to that produced by blowing on a 

 dry plate. This shows that the electricity of the streams of powder issuing out 

 of the bellows is only contrary to the more expanded part, because it is within 

 the influence of its atmosphere ; for when this is destroyed by the adhesion of 

 the powder to the moistened plate, it is negative when the bellows are positive, 

 as it was before positive when the more expanded cloud was negative. He also 

 adds, that the experiments on evaporation of water may be tried with more ease 

 and certainty of success by heating the small end of a tobacco-pipe, and pouring 

 water into the head, which, running down to the heated part, is suddenly ex- 

 panded, and will show its electricity when projected on the cap of the electro- 

 meter, more sensibly than any other way he had tried. If the pipe be fixed in 

 a cloven stick, and placed in the cap of one electrometer, while the steam is 

 projected on another, it produces both electricities at once. Spirit of wine and 

 ether are electrified like water. Oil and vitriolic acid produced smoke without 

 any change of electricity. In these experiments a long pipe is better than a 

 short one. 



VI. Some Account of an Earthquake felt in the Northern Part of England. By 

 Samuel More, Esq. Dated Castle-Head, Lancashire, Aug. 22, 1786.' 

 p. 35. 



This shock of an earthquake was felt in Cumberland and the neighbouring 

 counties, on Friday, Aug. 1 1, this year, about 2 o'clock in the morning. 



