MECHANICS AND USEFUL ARTS. 91 



A few years ago a method of making seamless sugar bags direct from the 

 pulp, and without the Intel-mediate stage of sheet paper having been invented, 

 an inquiry was made in regard to its applicability for cartridges, and it 

 having appeared, after careful examination, to offer several important ad- 

 vantages, more especially with respect to strength with a given quantity of 

 paper, economy, and still more in regard to accuracy of dimensions, that 

 system has, accordingly been introduced. 



The special apparatus required for the small-arm seamless cartridge bag 

 consists of a number of small perforated moulds, of the same form as the 

 cartridge bag, which are clustered together on the end of a flexible pipe, in 

 which a vacuum is kept up by means of an air pump. Each finger in this 

 group of moulds is covered with a worsted slip cover, or mitten, and the 

 whole cluster is then dipped into a cistern containing the liquid pulp, which 

 in an instant is drawn upon them through the agency of the internal vacuum, 

 combined with the external pressure of the atmosphere. The worsted mit- 

 tens, with their paper covering, are then placed on driers of the exact di- 

 mensions, that arc heated by steam, the whole operation of forming and 

 drying occupying about a quarter of an hour. 



IMPROVEMENT IN THE MANUFACTURE OF GUNPOWDER. 



A patented improvement, by Henry Hodges, of New York, consists in 

 mixing the ingredients or component parts of gunpowder (namely, charcoal, 

 saltpetre and sulphur) in their usual proportions in the ordinary way, and 

 in then putting them into a suitable pot or vessel, made of any description 

 of metal or earthenware, into which vessel sufficient steam is admitted by 

 any suitable apparatus to damp the composition, dissolve the saltpetre, and 

 soften the sulphur. By these means the saltpetre is more intimately blended 

 with the other ingredients than by ordinary processes of manufacture. 

 During this process the composition should be kept well stirred up, to ex- 

 pose it as much as possible to the action of the steam, and this may be con- 

 tinued until the whole of the saltpetre is dissolved, when it is taken out, and 

 when sufficiently dry is ground in the usual way. 



IMPROVEMENTS IN POLISHING AND GRINDING PLATE GLASS. 



The New York Tribune furnishes the following description of a new 

 method of polishing and grinding plate glass, recently put in operation by 

 a new company, in New York City. 



The apparatus in question is the invention of Mr. Brougton, improved 

 by Mr. P. Burgess. The grinder is a horizontal circular plate of cast-iron, 

 ten feet in diameter, and two inches thick. The upper surface is planed, 

 and has ribs beneath to give it strength. This large plate is keyed on the 

 end of a vertical shaft, which is made to revolve at a velocity of forty-five 

 revolutions a mimite. Two horse power is all that is required. The plate 

 of glass to be ground is placed upon the circular table just described; half- 

 way between the centre and the circumference an adjustable frame of the 

 proper weight is placed upon it so as to confine the edges and prevent the 



