HYDRAULIC ENgINE. 35 



hy It, at pleafure. The perfon who holds it may dired the Machlna for 

 fcraper in its proper line, and affifi: it in overcoming any oh- ^^^^^^'^J^^ * 

 ilacles it may meet with in its way, or in giving it additional 

 preflure where neceflary. 



II. Show the two parts of the machine which form the 

 feet, or fledge part of the machine, on which it Aides when 

 reverfed, and which enable it to be removed from place to 

 place, when the fcraper is not in ufe. Thefe feet are ftrongly 

 fixed to the timbers A A, and ftrengthened by a tranfverfe 

 brace betwixt them. 



L. Is the iron chain, or back band, which lies upon the 

 cart-faddle of the horfe in the fliafts, and which fupports the 

 fliafts. 



Fig. 2. Shows, on an enlarged fcale, the iron-work, fixed 

 on the outfide of the fliafts, to which the chain and horfe are 

 attached. 



Fig. 3. Defcribes, in a fmall extent, the track ufually 

 made by the fcraper in a large way, in four rows, commenc- 

 ing at the arrow mark, in the track No. 1, returning after it 

 has gone any length required by the track No. 2, proceeding 

 again by the track No. 3, and forcing the mud colle6led by 

 the tracks No. 1 and 3 to the right fide of the road, and, on its 

 return by the track No. 4, depofiting the mud of the tracks 

 No. 2 and 4 on the left of the road, as is more fully defcribed 

 in the preceding account, and thus clearing from mud a breadth 

 of road twenty feet wide, by four paflages of (he machine. 



IX. 



Defcription and Draiving of an Hi/draidic Machine, tvith an 

 Account of feveral Inventions of early Date, which have been 

 fince brought forward by later Inventors. Extra6ied from a 

 Foreign Work publijhed early in the lafi Century. By a 

 Correfpondeut. 



To Mr. NICHOLSON. 

 SIR, 



1 HAVE lately met with a work in French, entitled Recueil Account of the 

 d'Ouvracres curieux de Mathematique et ?>4ccaniqne, ou Defcrip- P^°''"tion of 



7 1 J ^^ ^ /,• I ■ • theMufeumof 



tion du Cabinet de Monf. Groilier de Serviere, in quarto, Monf. de Ser- 



D 2 printed viere. 



