FULMINATING MERCURY 



511 





William and Ogle introduced in 1825 some new fulling machinery, designed to act 

 in a similar way to the ordinary stocks, in which cloths are beaten, for the purpose of 

 washing and thickening them ; but the standard and the bed of the stocks are made 

 of iron instead of wood, as heretofore ; and a steam vessel is placed under the bed, for 

 heating tho cloths during the operation of fulling, whereby their appearance is said to 

 be greatly improved. 



Fig. 1006 is a section of the fulling machine or stocks: a, is a cast- iron pillar, 

 made hollow for the sake of lightness ; b, is the bed of the stocks, made also of iron, 

 and polished smooth, the side of the 1QQ6 



stock being removed to show the in- 

 terior ; c, is the lever that carries the 

 beater d. The cloths are to be placed 

 on the bed b, at bottom, and water 

 allowed to pass through the stock, 

 when by the repeated blows of the 

 beater d, which is raised and let fall 

 in the usual way, the cloths are 

 beaten, and become cleansed and 

 fulled. 



A part of the bed at e is made 

 hollow, lor the purpose of forming a 

 steam box, into which steam from a 

 boiler is introduced by a pipe with a 

 stopcock. This steam heats the bed 

 of the stock, and greatly facilitates, 

 as well as improves, the process of 

 cleansing and fulling the cloths. 



The smoothness of the surface of the polished metal, of which the bed of the stock 

 is constituted, is said to be very much preferable to the roughness of the surface of 

 wood of which ordinary fulling stocks are made, as by these iron stocks less of the nap 

 or felt of the cloth is removed, and its appearance when finished is very much superior 

 to cloths fulled in ordinary stocks. 



In the operation of fulling, the cloths are turned over on the bed by the falling of 

 the beaters, but this turning over of the cloths will depend in a great measure upon 

 the form of the front or breast of the stock. In these improved stocks, therefore, 

 there is a contrivance by which the form of the front may be varied at pleasure, in 

 order to suit cloths of different qualities ; /, is a moveable curved plate, constituting 

 the front of the stock ; its lower part is a cylindrical rod, extending along the entire 

 width of the bed. and being fitted into a recess, forms a hinge joint upon which the 

 curved plate mores ; g, is a rod attached to the back of the curved plate /, with a 

 screw thread upon it ; this rod passes through a nut /?, and by turning this nut, tho 

 rod is moved backward or forward, and, consequently, the position of the curved plate 

 altered. 



The nut k, is a wheel with teeth, taking into two other similar toothed wheels, one 

 on each side of it, which are likewise the nuts of similar rods jointed to the back of 

 the curved plate/; by turning the central wheel, therefore, which may be done by a 

 winch, the other two wheels are turned also, and the curved plate moved backward or 

 forward. At the upper part of the plate there are pins passing through curved slots, 

 which act as guides when the plate is moved. 



FULMINATING MERCURY, C 4 N 2 Hg'0 4 (C 2 U 2 HffO 2 ). The well-known 

 compound used for priming percussion caps. It was analysed many years ago by 

 Liebig, and subsequently, by Gay-Lussac. Although chemists have long been ac- 

 quainted with the true composition of fulminic acid, and the formula of fulminating 

 mercury has also been rendered almost certain, no accurate analysis of the latter com- 

 pound was made public until 1855, when M. Schischkoff published his celebrated paper 

 on the fulminates. It is singular that Liebig and Schischkoff were independently 

 engaged at the same time in investigating the products of decomposition of the fulmi- 

 nates. The formula of fulminic acid, and also that of fulminating mercury, had been 

 deduced from the very accurate analyses of fulminating silver made by Gay-Lussac 

 and Liebig. A great number of processes for the preparation of fulminating mercury 

 have been published. The following are the best as regards economy and certainty : 



1. One part of mercury is to be dissolved in 10 parts of nitric acid, sp. gr. 1-4 ; and 

 the solution at a temperature of 1J30 F. is to be poured into 8*3 parts of alcohol, 

 sp. gr. 0'830. Ure. 



2. One part of mercury is to be dissolved in 12 parts of nitric acid, of sp. gr. 1-3. 

 To the solution (as soon as it has cooled to 55 F.). 8 parts of alcohol, sp. gr. 0'837, 

 are to be added ; the vessel containing the mixture is to be heated in boiling water 



