446 Major-General ^^q>y\ Account of the 



A brafs ftrap or bridle, about eight-tenths of an inch broad, 

 paffes over the top of the cafe, and defcending down each fide, 

 bends outwards, fo as to form a projection for the reception of 

 the wheels, whofe pivots turn in, but near to the lower end 

 of the bridle, which is kept in its place by means of the two 

 fide fcrew^s working in grooves, and the milled-headed fcrew at 

 top. This laft ferves likewife to raife or deprefs the wheels at 

 plea fu re. 



Each rod has two crofs feet, placed immediately behind 

 their refpedtlve pair of wheels, extending outwards about 4I 

 inches from the center on each fide. Under their outward ex- 

 treniities, fmall pieces of hardened fteel, formed into the teeth 

 of a file, are fixed by means of fcrews. When the firft rod 

 has been laid in its true place, by unfcrewing the milled heads, 

 the wheels are fuffered to rife; whereby the whole weight is 

 removed from them, and thrown upon the teeth of the files, 

 which then indent themfelves into the furface of the ftand, 

 mid become as it were united to it. But when the fixed button 

 of the fecond rod is brought to prefs againfl the moveable but- 

 ton of the firfl, the weight being then thrown upon the 

 wheels by fcrewing the milled heads at top, the rod is eafily 

 moved on by the following apparatus. 



The three rods are numbered, as were thofe of deal, 1.2; 3.4 ; 

 £.6. On the firft or odd end of each rod i. 3. and 5. there ftands 

 a brafs fork, about two inches high, fixed by four fcrews and aii 

 oblong plate to the top of the cafe. On the fecond, or even 

 end of each, 2. 4. and 6. there ftands a brafs pillar of the fame 

 height with the fork, likewife fixed to tlie top of the cafe by 

 foiir fcrews and a circular plate. Two fteels rods or hooks 

 were indifferently ufed for bringing up the moveable rod (the 

 weight then lying ou the wheels) into its true place. They 



are 



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