ENG 



ENG 



the great wheel and drum : B, the great 

 wheel with cogs, that turns a trundle 

 head with a fly, to prevent the horse's 

 falling when the ram is discharged; C, 

 the drum on which the great rope is 

 wound ; D the follower (with a roller at 

 one corner) in which are contained the 

 tongs, to take hold of the ram, and are 

 fastened to the other end of the great 

 rope, which passes over the pulley, near 

 the upper end of the guides, between 

 which the ram falls ; E, the inclined 

 planes, which serve to open the tongs, 

 and discharge the ram ; F, the spiral 

 barrel that is fixed to the drum, on 

 which is wound a rope with a counter- 

 poise, to hinder the follower from acce- 

 lerating, when it falls down to take up 

 the ram ; G, the great bolt which locks 

 the drum to the great wheel ; H, the 

 small lever, which has a weight fixed at 

 one end, passes through the great shaft 

 below the great wheel, and always tends 

 to push the great bolt upwards, and lock 

 the drum to the great wheel ? I, the 

 forcing bar, which passes through the 

 hollow axis of the great shaft, bears upon 

 the small lever, and has near the upper 

 end a catch, by which the crooked lever 

 keeps it down ; K, the great lever, which 

 presses down the forcing bar, and dis- 

 charges the great bolt at the time the 

 long end is lifted up by the follower ; L, 

 the crooked lever, one end of which has 

 a roller, that is pressed upon by the 

 great rope, the other end bears upon the 

 catch of the forcing bar during the time 

 the follower is descending ; M, the spring 

 that presses against the crooked lever, 

 and discharges ,it from the catch of the 

 forcing bar as soon as the great rope 

 slackens, and gives liberty to the small 

 lever to push up the bolt. 



By the horse's going round, the great 

 rope is wound about the drum, and 

 the ram is drawn up, till the tongs 

 come between the inclined planes, where 

 they are opened, and the ram is dis- 

 charged. 



Immediately after the ram is discharg- 

 ed, the roller, which is at one end of the 

 follower, takes hold of the rope that is 

 fastened to the long end of the great 

 lever, and lifts it up ; the other end 

 presses down the forcing bar, unlocks the 

 drum, and the follower comes down by 

 its own weight. 



As soon as the follower touches the 

 ram, the great rope slackens, and the 

 spring, M, discharges the crooked lever 

 from the catch of the forcing bar, and 

 jjives liberty to the small lever to push 



VOL. V. 



up the great bolt, andto lock the drum to 

 the great wheel, and the ram is drawn up 

 again as before. 



ENGINEER, in the military art, an 

 able, expert man, who, by a perfect know- 

 ledge in mathematics, delineates upon 

 paper, or marks upon the ground, 

 all sort of forts, and other works pro- 

 per for offence and defence. He should 

 understand the art of fortification, so as 1 

 to be able, not only to discover the de- 

 fects of a place, but to find a remedy 

 proper for them, as also how to make an 

 attack upon, as well as to defend, the 

 place. Engineers are extremely neces- 

 sary for these purposes : wherefore it is 

 requisite that, besides being ingenious, 

 they should be brave in proportion. 

 When at a siege the engineers have nar- 

 rowly surveyed the place, they are to 

 make their report to the general, by ac- 

 quainting him which part they judge the 

 weakest, and where approaches may be 

 made with most success. Their busi- 

 ness is also to delineate the lines of cir- 

 cumvallation and contrarallation, taking 

 all the advantages of the ground; to 

 mark out the trenches, places of arms, 

 batteries, and lodgments, taking care 

 that none of their works be flanked 

 or discovered from the place. After 

 making a faithful report to the gene- 

 ral of what is doing, the engineers are 

 to demand a sufficient number of work- 

 men and utensils, and whatever else is 

 necessary. 



ENGRAFTING or GRAFTING, in gar- 

 dening. See the article GRAFTING. 



ENGRAILED, or INGRAILEP, in he- 

 raldry, a term derived from the French, 

 hail; and signifying a thing the hail 

 has fallen upon and broke off the edges, 

 leaving them ragged, or with half rounds, 

 or semicircles, struck out of their edges. 



ENGRAVING. This term is at pre- 

 sent confined to the art of excavating 

 copper and wood, in lines, in so judicious 

 a manner, as to produce imitations of 

 paintings and drawings when painted on 

 paper. It is certain that engraving for 

 the production of prints was unknown 

 long after the practice of painting in oil 

 had arrived to great perfection, but good 

 prints are common from plates engraved 

 in the fifteenth century, many of which 

 are landscapes, most laboriously, and 

 even excellently, performed by the gra- 

 ver, although it is well known that the 

 instrument just mentioned cannot freely 

 express those serrated and serpentine 

 lines, necessary for foliage and short 



D 



