1821.] On an Apparatus for discharging Ordnance. 



Article II, 



Explanation of aii Apparatus ^ suggested bi/ Col. Yule, for discharge 

 ing Ordnance, upon Mr. Forcyth's Plan; and an Account of 

 some curious Experiments performed with itJ^' By Mr. John 

 Deuchar, Lecturer on Chemistry in Edinburgh. (With a Plate.) 



It is proposed, in the present paper, first to explain an appa- 

 ratus some time ago suggested by Col. Yule, for applying Mr. 

 Forcyth's plan to the discharge of ordnance, without either the 

 use of ahght, or the usual prime ; and secondly, to give a very- 

 brief account of several experiments which I have performed 

 with it. 



(I.) The apparatus has first to be noticed: it is very simple. 

 It consists of a thick brass tube (see Plate III), fig. I, A B, 

 15 inches long, which is meant to represent the touchhole of 

 the gun ; the diameter of the bore of this tube, fig. 6, is about 

 the 18th or 20th part of an inch ; it terminates at the top. A, in 

 a cup, fig. 3, dj at the bottom of which the bore of the tube is 

 divided into three very small holes, fig. 4, to prevent the powder 

 falling into the wider tube : into this cup about one grain of the 

 new composition, afterwards alluded to, is put, when the appa- 

 ratus is to be used. At the top of the apparatus is a bar of 

 brass, C D, which at the one end, D, turns upon a joint/and at 

 the other, C, is supphed with a cap, in the centre of which is a 

 steel projection or hammer, fig. 2, e; the cap covers the whole 

 of the raised part. A, at the top of the tube, A B ; and the ham- 

 mer nearly fits the cup, fig. 3, d, and is made to strike flat upon 

 the bottom of it, fig. 4, d. Between the joint of the bar, D, and 

 the top of the tube. A, is placed a piece of cork, I, or any other 

 elastic substance, to prevent the steel hammer, e, coming too 

 close upon the composition before it is struck, and to make it 

 spring back again after the discharge. The apparatus is united 

 at the top by a frame of brass, G H, which, to prevent its being 

 injured by the firing, is screwed upon another frame of wood, 

 E F. The tube, A B, screws into four pieces ; and it was into 

 the hollows left, «, the joinings of these, «, h, and c, by only half 

 screwing them, that the different substances we put which are 

 noticed in the experiments. 



Explanation of Plate. 



Fig. 1, represents the whole apparatus on a scale of 4-lOths to 

 1 inch. 



Y^Z' ^» gives a section of the cap, C, and steel hammer, f, 

 which strikes upon the powder at the top of the tube^ A B. -_iii^- 



• Read before the Wernerian Natural History Society, Dec 1 6, 1820. 



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