MECHANICS, 
790 
fome other method, in order that the prefl'ure fhould be 
equal at each fide. 1 only prefer the other conllruetion 
from its leaving a greater fpace for the inclined plane, 
and admitting the aftion of the air to be more certainly 
equal in all parts of the plane; but the laft plan will have 
the advanta'ge of being more conformable to the ufual 
limit lire, and of admitting the veil'd therefore to be dif- 
pofed of more eafily for common purpofes, if it fnould 
not be thought expedient to ufe it any longer as a fteam- 
boat, from its becoming too old, or from any other caufe. 
In this laft method, any veffel of a proper fize may be 
fitted up for this purpofe, by adding the air-cafes and the 
fences under the ftern, both difpofed as defcribed ; and 
particular care being taken that the external part of the 
air-cafes, forming the inclined planes, fhould be doped 
fufficiently, and that they fhould be made fo as to lie in 
the fame plane, if continued through the dead wood, and 
not in two feparate planes, or fo as to form an angle with 
each other, w hich would be the cafe if they were made 
to lie parallel to the run of common veffels beneath the 
counter. In this way the air-cafes will extend beyond the 
Herns of ordinary veffels, and will contain a greater fpace 
the nearer they approach to the fides of the veffel ; but 
this can occafion no material inconvenience. 
“ In all cafes the inclined planes fhould be continued 
in the fame direction two, three, or more, feet above the 
water, according to the fize of the veffel; becaufe the 
air in afcending will force along with it a confiderable 
mats of water, which will rife more above the furface as 
it is greater, and the air in afcending will a£t upon it in 
impelling the veffel in the fame manner as upon the lower 
■water, if the inclined planes are continued high enough. 
It will be obvious, that the vertical fences at the Tides 
of the inclined planes will give the veffel more hold of 
the water at the ftern, or caufe it to make a greater re¬ 
finance to lateral motion there than at the head ; but 
this, if found inconvenient in fleering the veffel, may be 
eafily remedied by increafing the fize of the cut-water, or 
by fhortening the bowfprit. In the figure, (129.) DD 
are the inclined planes; B B, the fide fences; CCC, the 
apertures for the delivery of the air; and E, the fide of 
the air-cafe. 
“ Veffels on this conftruetion will be preferable to fteam- 
boats on the ufual plan, for the reafons before flated, which 
enables them better and more fafely to be ufed at fea; 
and the following advantages, which velfels capable of 
being impelled by lteam at fta tnuft have over thol'e 
moved by fails alone, will, I prefume, convince any im¬ 
partial perfon that their adoption is an object of very 
great importance. 
3. A veffel impelled by an engine as defcribed, can go 
into port and out again, in nine cafes out of ten, where 
other veffels would be wind-locked. 
2. It would ef'cape all danger of lee-fhores, where other 
velfels would be loft. 
3. It could never be fubjecl to mifs flays in tacking, 
by which accident many veffels have been loft on fand- 
banks and rocks. 
4. In being chafed by an enemy equal in point of fail¬ 
ing, it could always efcape; as it would have the force of 
the engine to impel it, in addition to that of the fails. 
5. Veffels of war on this conftrudtion would have an 
advantage the reverfe of the laft, in being able to over¬ 
take other veffels not poffeffed of the fame apparatus ; and 
would, befides, be able always to get to the windward of 
other veffels of war when thought fit; to quit the engage¬ 
ment if worfted, when the fails and rigging of the adver- 
fary were difabled ; and at all times to get into the moll 
favourable pofition for the eft'eft of their guns, fo as to 
rake the adverfary fore and aft; and where the guns of 
the enemy, on the contrary, could do leaft injury. 
6 . Packets on this conflrudlion could convey letters and 
paffengers when others could not ftir out, by which means 
intelligence of the utmoll importance would no longer be 
delayed till the opportunity for action was loft, as often 
has happened from contrary winds; of which there was a 
remarkable inflance at the time the French attempted the 
invafion of Ireland at Bantry, when their whole fleet 
might have eafily been taken if intelligence could have 
been conveyed to England in time for tire Englifh fleet 
to fail from Plymouth; but the opportunity was loft by 
contrary winds, which prevented any veffels failing from 
Ireland at that time for more than a fortnight. 
7. Veffels on this plan would be more fafe in cafe of 
leaks, as the engine could eafily be made to work the 
pumps on fuch occafions. 
8. Veffels with a fleam-engine need not have fo many 
hands for mere failing, or in the merchant-fervice, fince 
the engine could be made to hoift the anchor, and raife 
and lower the yards, fails, and top-mafts, and do other 
work requiring much flrength, befides working the pumps. 
9. The (team-engine would be alfo ufeful in grinding 
flour for the crew, while the walte-ftearn could be ufed 
in cooking. And laft, though not leaft, the wafte-fteam 
would befides always afford a plentiful fupply of fre(h 
water, by an apparatus for condenfing it being added. 
“ When the method propofed is tiled in veffels of war, it 
will be ^material object to have all parts of the apparatus 
put out of reach of tliot as much as polhble; for which 
reafon it might be preferable for them, as the leaft of two 
rifks, to have the air conveyed at once through apertures 
in the bottom of the (hip, between the floor-timbers, fe- 
cured as well as poflible to the air pipes infide, fo as to 
be impervious to the air and water at the junctures; for 
by this means the whole of the apparatus may be placed 
in the hold, where no diredt (hot can reach.” 
II. Steam Carriages.— In March 1802, Meffrs. Trevithic 
and Vivian, of Camborne in Cornwall, obtained a patent 
for various improvements in (team-engines, and particu¬ 
larly for a Jleam-coach, or other carriage. A full account 
of thefe contrivances, with three outline engravings, may 
be feen in the Repertory of Arts, vol. iv. N. S. But, if 
fleam-boats are fometimes objected to on account of the 
noife of the engine and rhe fmell of the fleam, how much 
would thefe inconveniences be increafed in a clofe carriage! 
and we may join with.Ozanam (or Montucla) in thinking, 
that “it would not be very agreeable to travellers to hear, 
clofe behind them, the noife of a machine, capable, if it 
fhould burft, of blowing them to atoms.” 
But a patent fleam-carriage, invented by Mr. John Blen- 
kinfop, of Middleton-liall near Leeds, has been employed 
with great advantage in the coal-countries, for the con¬ 
veyance (not of paffengers, but) of coals, minerals, and 
other articles, along a railway ot a peculiar conftruetion. 
The engine ufed on the rail-road at Leeds is a four-horfe 
power, and is fo conftructed, that, by the operating aid of 
cran ks (fixed at right angles), it puts in motion a cogged 
wheel, adting in teeth call on one fide of the rail-road it- 
felf, ora feparate rack, by which a confiderable propelling 
power is given to the machine ; a power fo confiderable, 
that when the carriage is lightly loaded it travels at the 
rate of 10 miles an hour, but, when loaded with thirty 
coal-waggons, which is frequently the cafe, each weighing 
tons three and a half, it is propelled on a dead level at 
the rate of 3^ miles an hour. The ufe of thefe fleam- 
carriages has given the greateft fatisfaftion, and they pro¬ 
mile to be attended with the moll beneficial.effefts, parti¬ 
cularly as it is clearly afeertained that at lead fi ve-lixths of 
the expenfe of conveying goods by horfes will be faved 
by the invention. The (team-carriage has been fully em¬ 
ployed at Leeds fince June 1812; and, was not impeded 
even during the great falls of fnow in January 1813 ; for 
more waggons of coals were conveyed to Leeds in that 
fevere month, by the locomotive engine, than in any pre¬ 
ceding one by horfes. Thefe carriages are in conflantand 
daily ufe at Middleton colliery, Leeds, Yorkfhire; Orrell 
colliery, Wigan, Lancafter; and Kenton and Coxlodge 
collieries, near Newcaftle-upon-Tyne. The machine, at 
work is reprefen ted at fig. 130. where A is the boiler; 
B B, the rail-road; C, the propelling-wheel, which is 
1 put 
