III. Experimental researches in electricity. —eighteenth series

Abstract

2075. Two years ago an experiment was described by Mr. Armstrong and others, in which the issue of a stream of high pressure steam into the air produced abundance of electricity. The source of the electricity was not ascertained, but was supposed to be the evaporation or change of state of the water, and to have a direct relation to atmospheric electricity. I have at various times since May of last year been working upon the subject, and though I perceive Mr. Armstrong has, in recent communi­cations, anticipated by publication some of the facts which I also have obtained, the Royal Society may still perhaps think a compressed account of my results and con­clusions, which include many other important points, worthy its attention. 2076. The apparatus I· have used was not competent to furnish me with much steam or a high pressure, but I found it sufficient for my purpose, which was the in­vestigation of the effect and its cause, and not necessarily an increase of the electric development. Mr. Armstrong, as is shown by a recent paper, has well effected the latter. The boiler I used, belonging to the London Institution, would hold about ten gallons of water, and allow the evaporation of five gallons. A pipe 4½ feet long was attached to it, at the end of which was a large stop-cock and a metal globe, of the capacity of thirty-two cubic inches, which I will call the steam-globe , and to this globe, by its mouth-piece, could be attached various forms of apparatus, serving as vents for the issuing steam. Thus a cock could be connected with the steam-globe, and this cock be used as the experimental steam-passage; or a wooden tube could be screwed in; or a small metal or glass tube put through a good cork, and the cork screwed in; and in these cases the steam way of the globe and tube leading to the boiler was so large, that they might be considered as part of the boiler, and these terminal passages as the obstacles which, restraining the issue of steam, produced any important degree of friction.