E N G 
ENG 
present example, = s7 i horses ac- 
1194336 - 
cording to Watt and Boulton ; — **' ' •* 
1194336 
horses, according to Desaguliers ; and -ppp 
— 52’ horses, according to Smeaton. In 
this calculation it is supposed that the engine 
works only eight hours a day; so that it it 
wrought during the whole 24 hours, it would 
be equivalent to thrice the number of horses 
found by the preceding rule. We cannot 
help observing, and it is with sincere plea- 
sure that we pay that tribute of respect to 
tiie honour and" integrity of Messrs. Watt 
and Boulton which has every where been 
paid to their talents and genius,— that in 
estimating the power of a horse, they have 
assigned a value the most unfavourable to 
their own interests. W hile Mr. Smeaton 
and Dr. Desaguliers would have made the 
engine in the preceding example equivalent 
to 52 or 43 horses, the patentees themselves 
state that it will perform the work only ot 
37. How unlike is this conduct to some of 
our modern inventors, who ascribe powers 
to their machines which cannot possibly be- 
long to them, and employ the meanest arts 
for ensnaring the public ! 
Before we conclude this article, we shall 
state the performance of some of these en- 
gines, as determined by experiment. An 
enoine whose cvlmder is 31 inches in diame- 
ter, and which makes 17 double stiokes pel 
minute, is equivalent to 40 lioises, woiking 
day and night, and burns 11,000 pounds ot 
Staffordshire coal per day. W hen the cy- 
linder is nineteen inches, and the engine 
makes 25 strokes of 4 feet each per minute, 
its power is equal to that of 1 2 horses work- 
ing constantly, and it burns 3,700 pounds ot 
coals per day. And a cylinder of 24 inches 
which makes 22 strokes oi a feet each, pei- 
forms the work of 20 horses, working con- 
stantly, and burns 5,500 pounds of coals. 
Mr. Boulton has estimated their perform- 
ance in a different manner. He states, that 
one bushel of Newcastle coals, containing 84 
pounds, will raise 30 million pounds one foot 
high; that it will grind and dress eleven 
bushels of wheat ; that it will slit and draw 
into nails 5 cwt. of iron ; that it will drive 
1,000 cotton spindles, with all the prepa- 
ration machinery, w'ith the proper velocity ; 
and that these effects are equivalent to the 
work of 10 horses. 
Engine to lower heavy weights. This 
method was described nearly a century ago, 
and is as follows: Suppose it w r as required 
to lower large stones from a building ; erect 
a frame A, set up a gin close by the side of 
the wall, and let the pulley (Plate Engines, 
li'-r. 9.) be firmly attached to this frame. 
Over this pulley must pass a cord, one end 
of which C has a hook to which the stone or 
other weight can be fastened: the other end 
D carries a vessel, which may be filled with 
water from the reservoir M on the ground 
at the bottom of the wall. Then, while one 
man is fixing the stone to the hook at the top 
of the wall, let another put water into the 
vessel D at the bottom till it nearly equals 
the weight of the stone; after which the stone 
will gradually descend to the ground, while 
the vessel D will be carried up to the funnel 
S, into which the water may be poured, and 
16 V 
£ N G 
thence conveyed by a wooden or leathern 
pipe to M. "Then the vessel D may be suf- 
fered to descend, and the hook C will be 
aised to be fiixed to another stone, and thus 
the operation may be repeated. 
The same method may be adopted in low- 
ering sacks from a granary, &c. The velo- 
city of the descending weight may be so re- 
gulated as to have any proportion to that 
hich gravity imparts to bodies falling freely: 
thus if \\ — w eight to be lowered, Y that of 
w — V 
the vessel of water, then — — : — — expresses the 
W -j- V 
ratio of the velocity, to that freely imparted 
by gravity when denoted by unity : thus it 
W 
V — — , the weight will fall through ~ of 
or about 54. feet in the first second: 
2 W 3 
, the weight will fall through ± 
of KYto, or 3\ feet, the friction not being 
taken into consideration. 
ENGINES, in military mechanics, are 
compound machines, made of one or more 
mechanical powers, as levers, pulleys, screws, 
&c. in order to raise, project, or sustain, 
any weight, or produce any effect which 
could not he easily effected otherwise. 
Engine to drive fuses, consists of a wheel 
with a handle to it, to raise a certain w eight, 
and to let it fall upon the driver, by which 
the strokes become more equal. 
Engine to drove fuses, has a screw fixed 
upon a three-legged stand, the bottom of 
which has a ring to place it upon the shell ; 
and at the end of the screw is fixed a hand- 
screw by means of a collar, which being 
screwed on the fuse, by turning the upper 
screw, draws out or raises the fuse. 
ENGINEER, is commonly applied to an 
officer who is appointed to inspect and con- 
trive any attacks, defences, &c. of a fortified 
place, or to build or repair them, & c. 
The art of fortification is an art which 
stands in need of so many others, and whose 
object is so extensive, and its operations ac- 
companied with so many various circumstan- 
ces, that it is almost impossible for a man to 
make himself master of it by experience 
alone, even supposing him born with all the 
advantages of genius and disposition possible 
for tiie knowledge ainl practice of that im- 
poitant art. We do not pretend to deny 
that experience is of greater efficacy than all 
the precepts in the world; but it has likewise 
its inconveniences as well as its advantages: 
its fruits are of slow growth ; and whoever is 
content with pursuing only that method of 
instruction, seldom know r s how to act upon 
emergencies of all kinds, before old age inca- 
pacitates him from exercising his employ- 
ment. Experience teaches us through the 
means of the errors we commit ourselves, 
what theory teaches us . at the expence of 
others. The life of man being short, and 
opportunities of practice seldom happening, 
it is certain nothing less than a happy ge- 
nius, a great share of theory, and intent ap 
plication joined to experience, can make 
an engineer expect to shine in his profession. 
Whence it follows, that less than the three 
first of those four qualities should not be a 
recommendation for the reception of a young 
gentleman into the corps of engineers. 
The fundamental sciences, or those abso 
ENG 6 29 
lutelv necessary 7 , are arithmetic, geometry, 
mechanics, hydraulics, and drawing. With- 
out arithmetic, it is impossible to make a cal- 
culation of the extent, and to keep an ac- 
count of the disbursements made or to be 
made ; nor without it can an exact computa- 
tion Ire made upon any occasion whatsoever. 
Without geometry, it is impossible to lay 
down a plan or map with truth and exact- 
ness, or settle a draught of a fortification, or 
calculate the lines and angles, so as to make 
a just estimation, in order to tiace them on 
the ground, and to measure the surface and 
solidity of their parts. Mechanics teach us 
the proportions of the machines in use, and 
how to increase or diminish their powers as 
occasion may require; and likewise to judge 
whether those which our own imagination sug-t 
gests to us will answer in practice. Hydrau- 
lics teach us how to conduct waters from one 
place to another, to keep them at a certain 
height, or to raise them higher. How tlu- 
ently soever we may express ourselves in 
speaking or writing, we can never give so 
perfect an idea as by an exact drawing ; and 
often in fortification both are wanted, for 
which reason the art of drawing is indispen- 
sably necessary for engineers. 
To the qualities above mentioned must be 
added activity and vigilance ; both which are 
absolutely necessary in all operations of w ar, 
but especially in the attack of such places as 
are in expectation of succours. The besieged 
must have no time allowed them for consi- 
deration; one hour lost at such a juncture- 
often proves irreparable. It is by their acti- 
vity and vigilance, that engineers often bring 
the besieged to capitulate much sooner titan 
they would have done if those engineers had 
not" pushed on the attack with firmness and 
resolution. Want of vigilance and activity, 
often proceed from irresolution, and that 
from weakness of capacity. 
As the office of an engineer requires great 
natural qualifications, much knowledge,, 
study, and application, it is but reasonable 
that the pay should be proportioned to that 
merit which is to be the qualification of llr? 
person employed : he must be at an ex'n.crdi- 
nary expence in his education, and afterwards 
for books and instruments for his instruction 
and improvement, as well as for many other 
things; and that he may be at liberty to pur- 
sue his studies with {application, he must not 
be put to shifts for necessaries. It should 
likewise be considered, that if an engineer does 
his duty, be his station what it will, his fa- 
tigue must be very great; and to dedicate 
himself wholly to that duty, he should be di- 
vested of all other cares. 
The word engineer is of modern date, and 
was first used about the year 1650, when 
captain Thomas ltudd had the title of chief 
engineer to the king. In 1600, the title 
given to engineers was trench-master; and 
in 1622, sir William Pelham, and after him 
sir Francis Yere, acted as trench-masters in 
Flanders.. In the year 1634, an engineer was 
called camp-master general, and sometimes, 
engine-master, being always subordinate to 
the master of the ordnance. 
At present the corp of royal engineers in 
England' consists -of one colonel in chief, one 
colonel en second, one chief engiueer, five, 
colonels, six lieutenant-colonels, 18 captains, 
15 captain-lieutenants and captains, 31 lieu- 
,- tenants, and 1 6 second lieutenants. Thq-eSta- 
