W H. WEEKESj ESQ. 



299 



an opening of two inches diameter. Into this opening a thick me 

 tallic plug, or stopper, cast from " fusible alloy," is fitted perfectly 

 air-tight, by a process of long and careful grinding. Perpendicu- 

 larly through the metallic stopper, and at the distance of an inch 

 from each other, so as to occupy the extremes of an equilateral 

 triangle, are drilled three holes, each rather more than two-tenths 

 of an inch diameter, and into each of these is soldered, air-tight, a 

 corresponding glass tube. The two principal of this series of tubes 

 serve the purpose of insulating a pair of stout copper wires, which 

 pass longitudinally through them, and are united at each end by a 

 joint fusion of the glass and metal. Two other wires of platina 



Croeeed from the lower ends of the copper wires to nearly the 

 ottom of the jar, where they terminate in closely -wound spirals, 

 rather more than an inch apart, while the ends of the copper wires, 

 projecting from the upper ends of their respective tubes, have 

 conical cavities drilled out for the reception of a globule of mer- 

 cury, by means of which communication with the voltaic battery 

 is established. The third tube, passing first to the depth of an inch 

 below the metallic plug, is bent above the latter into a siphon 

 form, and contains in its curvature a globule of mercury weighing 

 about three drachms, which acts as a valve for the occasional 

 escape of gaseous matter generated within the close vessel, and is, 

 at the same time, a guarantee against the ingress of any species of 

 insect life. The mercury employed to form this valve was cau- 

 tiously distilled from the red sulphuret of that metal. 



By the side of the close vessel above described was placed, in 

 the first instance, a glass tumbler, capable of holding half a pint 

 of liquid. Through two pieces of mahogany, cemented to oppo- 

 site inner surfaces of this second vessel, were made to pass two 

 stout copper wires, terminating, like those adapted to the close jar, 

 in platina spirals a little more than an inch apart near the bottom 

 of the tumbler. The upper ends of these wires were similarly 

 provided with longitudinal cavities also, drilled out for the recep 

 tionof small globules of mercury, to complete contact and facili- 

 tate intercommunication. 



On the 2d of May, 1842, the apparatus, of which a description 

 has been attempted, was set to work after the following manner: 

 A solution of ferrocyanate of potass, prepared by carefully boiling 

 two ounces of the salt in sixteen ounces of distilled water, being 

 in readiness for the occasion, ten ounces of the liquid were trans- 

 ferred to the glass jar, and immediately after an elastic metal pipe, 

 in communication with an iron bottle in a state of white heat, and 

 from which a stream of pure oxygen rapidly proceeded, was dipped 

 into the solution in the jar. In this way, the gas, without passing 

 through water, or being brought in contact with any external 

 agent, continued to be supplied to the jar, until the entire atmo- 

 sphere above the solution consisted of oxygen alone, when the 

 metallic plug was deposited instantly in the neck of the jar, so as 

 to cut off all communication with the external air. The open 

 vessel or tumbler being now placed by the side of the close appa- 

 ratus, and four ounces of the solution before mentioned having 

 been poured into it, the necessary communication between the 

 two vessels was effected by means of suitable wires, and contact 

 at the same time similarly established with the respective poles of 

 a constant battery of ten pairs. By means of this arrangement, 

 the current entered the open vessel first, and then proceeded 



