i/^6 %Temotr on the Supply and 



ihv attention to this fubjeft is the produclion of a machine, 

 of which there follows an engraving and defcription. 



When it was firll fliown to the gentlemen of the Chemical 

 Society, fome of them beltowed on it the appellation oi gafo- 

 metcr', but, as etymology docs not authorize this name, it 

 has been changed for that oS. hvdroJlaUc blow-pipe. 



Fig. I . (fee plate VI.) is a perfpe<ilive engraving of the hy- 

 droftatic blow-pipe. Part of this figure is made tranfparent, 

 that the internal confiru6lion of the machine may be under- 

 ftood with the greater facility. 



It confifts of a cafk A, whofe length is thirty-two, and 

 whofe Icaft diameter is eighteen inches. It is divided, by 

 the partition B, into two apartments. The upper and external 

 apartment B A, is in depth fourteen inches. The lower and 

 internal apartment BC, is in depth fixteen inches; and con- 

 tains a ftieet and pipe of copper EE, D, which defcend into 

 it nine inches, forming two equal compartments of that 

 depth. The fiieet and pipe of copper are foldered together 

 and inferted into the partition B, as may be obferved at 

 iig. 2; where B reprefents the partition, EE the flieet of 

 copper, and D the pipe. The edges EB^ of the flieet were 

 (lid down into correfponding joints in the ftaves of the caflc 

 until the partition attained its proper fituation. Coopers' 

 flags were then pafled into the joints ^ and the hoops were 

 driven on the caflc. 



CF, fig. I. is a pair of circular bellows. The bottom of 

 the cafk. ferves as a bottom for thefe bellows. In the centre 

 of this bottom there is a hole, round which, at the diftance 

 of one inch from its centre, is a circular rim of wood. On 

 tiiis is nailed a valve opening upwards, which may be ob- 

 ferved at B, fig. 3, where there is a tranfparent engraving of 

 the bellows. Under the valve B may be obferved the hole, 

 and circular rim of wood, over which it is nailed. C the top 

 of the bellows, is a circular piece of wood, feven inches in 

 diameter and two in thicknefs. In its centre there is a hole 

 one inch and a half in diameter. Around this hole there 

 is a circular rabbet, in which is nailed a valve, opening up- 

 wards. This valve, and the rabbet in which it is faftened, 

 mav be feen under the letter D, at the end of the rod. There 

 is alfo in this top, at the diitance of one inch from its peri- 

 meter, a circular dove-tailed furrow filled with lead, E. The 

 body of the bellows F F, i.'^ compofed of ftrong hofe-leather 

 fo as to be water-tight. Before it was fixed to the other parts 

 of the bellows its form was that of a hollow frufl:um of a 

 .cone, of which the perpendicular and greatell diameter were 



each 



