Jack.

a

Smoke- proportion of the velocity of the vane to that of the one, there is a quadruple impulse acting at half the di- Smoke
Jack. current of heated air. This is subject to no rule, being stance from the axis. The momentum or energy there.

changed according to the load of the jack. We ima fore of the current is double. Therefore, supposing the
gine that an obliquity of 65 degrees for the outer endspinion, wheel, and pulleys of both jacks to be the same,
of the vanes will be a good position for the generality The jack with the small fly, placed in the narrow part of
of cases. Messinger describes an ingenious contrivance the vent, will be 16 times more powerful.
for changing this angle at pleasure, in order to vary the By this example, more easily understood than a ge-
velocity of the motion. Each vane is made to turn neral process, it appears that it is of particular imper-
round a midrib, which stands out like a radius from the tance to place the fly in an elevated part of the vent,
spindle, and the vane is moved by a stiff wire attached to where the area may be much contracted. In order still
one of the corners adjoining to the axle. These wires farther to increase the power of the machine, it would
are attached to a ring which slides on the spindle like be very proper to lengthen the spindle still more, and to
the spreader of an umbrella ; and it is stopped on any put another fly on it at a considerable distance above the
part of the spindle by a pin thrust through a hole in tlie first, and a third above this, &c.
spindle and ring. We mention this briefly, it being As the velocity of the current changes by every
easily understood by any mechanic, and but of little con- change of the fire, the motion of this jack must be very
sequence, because the machine is not susceptible of much unsteady. To render it as adjustable as may be to the
precision.

particular purpose of the cook, the pulley E has several
It is easy to see that an increase of the surface of the grooves of different diameters, and the spit turns more
vanes will increase the power: therefore they should oc- or less slowly, by the same motion of the fly, according
cupy the whole space of the circle, and not consist of as it bangs in the chain by a larger or smaller pulley or
four narrow arms like the sails of a windmill. It is bet- groove.
ter to make many narrow vanes than a few broad ones; Such is the construction of the smoke-jack in its most
as will appear plain to one well acquainted with the simple form. Some are more artificial and complicated,
mode of impulse of fluids acting obliquely. We recom- having, in place of the pulleys and connecting chain, a
mend eight or twelve at least ; and each vane should spindle coming down from the horizontal axis BC. On
be so broad, that when the whole is held perpendicular the upper end of this spindle is a horizontal contrate
between the eye and the light, no light shall come wheel, driven by a pivion in place of the pulley C. On
through the fly, the vanes overlapping each other a very the lower end is a pinion, driving a contrate wheel in
small matter. We also recommend the making them place of the pulley E. This construction is represent-
of stiff plate.

Their weight contributes to the steady ed in fig. 6. Others are constructed more simply, in Fig. 6.
motion, and enables the fly, which bas acquired a con- the manner represented in fig. 7. But our first con- Fig. 7.
siderable velocity during a favourable position of things, struction has great advantage in point of simplicity, and
to retain a momentum sufficient to pull round the spit allows a more easy adjustment of the spit, which may be
while the heavy side of the meat is rising from its lowest brought nearer to the fire or removed farther from it
position. In such a situation a light fly soon loses its without any trouble ; whereas, in the others, with a
momentum, and the jack staggers under its load. train of wheels and pinions, this cannot be done with.

It is plain, from what has been said, that the fly should out several changes of pins and screws. The only im. occupy the whole of that section of the vent where it is perfection of the pulley is, that by long use the grooves placed. The vent must therefore be brought to a round become slippery, and an ill-balanced joint is apt to hold form in that place, that none of the current may pass

back the spit, while the chain slides in the grooves. uselessly by it.

This may be completely prevented by making the
It is an important question where the fly should be grooves flat instead of angular (wbich greatly diminisbes
placed. If in a wide part of the vent, it will have a the friction), and furnishing them with short studs or
great surface, and act by a long lever; but the current pins which take into every third or fourth link of the
in that place is slow, and its impulse weak. This is a fit chain. If the chain be made of the simplest form, with
subject of calculation. Suppose that we have it in our fat links, and each link be made of an exact length
choice to place it either as it is drawn in the figure, or (making them all on a mould), the motion will be as
farther up at g, where its diameter must be one half of easy as with any wheelwork, and without the least
what it is at G. Since the same quantity of heated air

chance of slipping:
passes through both sections, and the section g has only It is always of importance to avoid this slipping of
one-fourth of the area of the section G, it is plain that the chain by balancing the loaded spit. For this pur-
the air must be moving four times faster, and that its im- pose it will be extremely convenient to bave what is
pulse is 16 times greater. But the surface on which it called a bulance-skeuer. Let a part of the spit, imme-
is acting is the fourth part of that of the fly G; the ac- diately adjoining to the pulley, be made round, and let
tual impulse therefore is only four times greater, suppo- an arm be made to turn on it stiffly, so that it may be
sing both flies to be moving with the same relative ve. made fast in any position by a screw. Let a leadeu ball
locity in respect of the current; that is, the rim of each be made to slide along this arm, with a screw to tasten
moving with the same portion of the velocity of the cur- it at any distance from the spit. When tbe meat is
rent. This will be the case when the small fly turns spitted, lay it on the racks, and the heaviest side will
eight times as often in a minute as the large fly : for immediately place itself undermost. Now turn round
the air is moving four times as quick at g, and the dia- the balance-skewer, so that it may point straight up.
meter of g is one-half of that of G. Therefore, when wards, and make it fast in that position by the screw.
the small fly is turning eight times as quick as the great Put the leaden ball on it, and slide it inwards or out-

wards

a

a

I

it is put.

m

a

a

year

a

Smoke- wards till it exactly balances the heavy side, which will After all, we must acknowledge that the smoke.jack Smoke-
Jack.
appear by the spit's remaining in any position in which is inferior to the common jack that is moved by a weight. Jaok
It is more expensive at first, and requires more frequent

Smollet.
The greatest difficulty is to keep the machine in re- repairs; its motion is not so much under command; it
pair. The essential part of it, the first mover, the fly, occasions soot to be thrown about the fire, to the great
and the pinion and wheel, by which its motion is trans. annoyance of the cook; and it is a great encumbrance

. mitted to the rest of the machine, are situated in a place when we would clean the vent. of difficult access, and where they are exposed to vio- SMOKE-Farthings. The pentecostals or customary lent heat and to the smoke and soot. The whole weight oblations offered by the dispersed inhabitants within a of the fly, resting on the lower pivot I, must exert a diocese when they made their procession to the mother great pressure there, and occasion great friction, even or cathedral church, came by degrees into a standing when this pinion is reduced to the smallest size that is annual rent called smoke farthings. compatible with the necessary strength. The pivot must Smoke Silver. Lands were holden in some places by be of hardened steel, tapered like an obtuse cone, and the payment of the sum of 6d. yearly to the sherifi, must turn in a conical socket, also of hardened steel or called smoke-silver (Par. 4. Edw. VI.). Smoke-silver of bell-metal; and this seat of pressure and friction must and smoke penny are to be paid to the ministers of dibe continually supplied with oil, which it consumes very vers parishes as a modus in lieu of tithe-wood: and quickly. It is not sufficient that it be from time to time in some manors formerly belonging to religious houses, smeared with an oiled feather; there must be an iron there is still paid, as appendant to the said manors, the cup formed round the socket, and kept filled with oil. ancient Peter-pence, by the name of Smoke-money It is surprising how quickly it disappears; it soon be- (T'wisd. Hist. Vindicat. 77.).—The bishop of London comes clammy by evaporation, and by the soot which anno 1444, issued out his commission, Ad levandum le gathers about it. The continued rubbing of the pivot smoke-farthings, &c. and socket wears them both very fast; and this is in- SMOLENSKO, a large and strong city of Russia, creased by hard powders, such as sandy dust, that are and capital of a government of the same name, with a hurried up by the rapid current every time that the eastle scated on a mountain, and a bishop's see. It is cook stirs the fire. These, getting between the rub strong by its situation. It has been taken and retaken bing parts, cause them to grind and wear each other several times by the Poles and Russians; but these last prodigiously. It is a great improvement to invert these have had possession of it ever since the 1687. It rubbing parts. Let the lower end of the spindle be of was taken by the French in their irruption into Russia a considerable thickness, and have a conical hollow nice. in 1812. It is seated on the river Nieper, near the ly drilled in its extremity. Let a blunt-pointed coni- frontiers of Lithuania, 188 miles south-west of Moscow. cal pin rise up in the middle of the oil cup, on which E. Long. 31. 22. N. Lat. 54. 50. tbe conical hollow of the spindle may rest. Here will SMOLENSKO, a government of Russia, bounded on be the same steady support, and the same friction as in the north by Twer, on the east by Moscow, on the the other way; but no grinding dust can now lodge be- south by Kalouga, and on the west by Witepek. It is tween the pivot and its socket : and if this upright pin full of forests and mountains, but is fertile in grain. be screwed up through the bottom of the cup, it may The population in 1815 was 965,000. be screwed farther up in proportion as it wears; and SMOLLET, DR Tobias, an author whose writings thus the upper pivot g will never desert its hole, a thing will transmit bis name with honour to posterity, was which soon happens in the common way.

born in the year 1720 at a small village within two from experience, that a jack constructed in this way will miles of Cameron, on the banks of the river Leven. not require the fifth part of the repairs of one done in He appears to have received a classical education, and the other way.

was bred to the practice of physic and surgery; and in It is of importance that thic whole be so put toge- the early part of his life served as a surgeon's mate in ther as to be easily taken down, in order to sweep the the navy. vent, or to be repaired, &c. For this purpose, let the The incidents that befel him during his continuance cross bar which carries the lower end of the upright in this capacity served as a foundation for Roderic Ranspindle be placed a little on one side of the perpendicu. dom, one of the most entertaining novels in the English lar line from the upper pivot hole. Let the cock which tongue. He was present at the siege of Carthagena; carries the oil cup and the pivot of the horizontal axis and in the before-mentioned novel he has given a faithBC be screwed to one side of this cross bar, so that the ful, though not very pleasing, account of the managecentre of the cup may be exactly under the upper pivot ment of that ill-conducted expedition, which he censures hole. By this construction we have only to unscrew in the warmest terms, and from circumstances which fell this cock, and then both axles come out of their places under his own particular observation. at once,

and may be replaced without any trouble. We His connection with the sea seems not to have been Fig .s. have sketched in fig. 8. the manner in which this may of long continuance; and it is probable that he wrote

be done, where M represents a section of the lower cross several pieces before he became known to the public by bar. BCDE is the cock, fixed to the bar by the pins his capital productions. The first piece we know of wwhich go through both, with finger nuts a and b on the with certainty is a Satire in two parts, printed first in opposite side. Fi is the hard steel pin with the conical the years 1746 and 1747, and reprinted in a Collection top i, on which the lower end I of the upright spindle of his Plays and Poems in 1777. About this period, or AG rests, in the manner recommended as the best and some time before, he wrote for Nir Rich an opera intitled most durable. The pivot of the horizontal axis turns Alceste, which has never been performed nor printed. in a hole at E the top of the cock.

At the age of 18 he wrote a tragedy intitled The

Regicide,

:

We can say

a

Smollet. Regicide, founded on the story of the assassination of degree of success was insured to every thing known or Smollet bir James I. of Scotland. In the preface to this piece, suspected to proceed from his hand. In the course of

published by subscription in the year 1749, he bitterly a few years, the Adventures of Peregrine Pickle apexclaimed against false patrons, and the duplicity of peared; a work of great ingenuity and contrivance in theatrical managers. The warmth and impetuosity of the composition, and in which an uncommon degree of his temper burried him, on this occasion, into unjust re- erudition is displayed, particularly in the description of flections against the late George Lord Lyttleton and the entertainment given by the Republican Doctor, afMr Garrick: the character of the former he character- ter the manner of the ancients. Under this personage ised in the novel of Peregrine Pickle, and he added a the late Dr Akenside, author of The Pleasures of Ima. burlesque of the Monody written by that nobleman on gination, is supposed to be typified; and it would be the death of his lady. Against Mr Garrick he made

difficult to determine whether profound learning or geilliberal ill-founded criticisms; and in his novel of Ro- nuine humour predominate most in this episode. Ana derick Random gave a very unfair representation of his other episode of the Adventures of a Lady of Quality, treatment of him respecting this tragedy. Of this con- likewise inserted in this work, contributed greatly to its duct he afterwards.repented, and acknowledged his er- success, and is indeed admirably executed; the materors ; 'though in the subsequent editions of the novel rials, it is said, the lady herself (the celebrated Lady the passages which were the basty effusions of disap- Vane) furnished. pointment were not omitted.

These were not the only original compositions of this However, in giving a sketch of the liberal arts in stamp with which the Doctor las favoured the public. his History of England, he afterwards remarked, " the Ferdinand Count Fathom, and Sir Launcelot Greaves, exhibitions of the stage were improved to the most ex- are still in the list of what may be called reading novels, qnisite entertainment by the talents and management of and have gone through several editions ; but there is no Garrick, who greatly surpassed all his predecessors of injustice in placing them in a rank far below the former, this and perhaps every other nation, in his genius for No doubt invention, character, composition, and conacting, in the sweetness and variety of his tones, the ir- trivance, are to be found in both ; but then situations resistible magic of his eye, the fire and vivacity of bis are described which are hardly possible, and characters actiòn, the eloquence of attitude, and the whole pathos are painted which, if not altogether unexampled, are at of expression.

least incompatible with modern manners; and which Not satisfied with this public declaration, he wrote ought not to be, as the scenes are laid in modern an apology to Mr Garrick in still stronger terms. With times. these ample concessions, Mr Garrick was completely sa- The last work which we believe the Doctor published tisfied; so that in 1757, when Dr Smollet's comedy of was of much the same species, but cast into a different the Reprisals, an afterpiece of two acts, was performed form— The Expedition of Humphrey Clinker. It conæt Drury Lane theatre, the latter acknowledged himself sists of a series of letters, written by different persons to highly obliged for the friendly care of Mr Garrick ex- their respective correspondents. He has here carefully ested in preparing it for the stage; and still more for avoided the faults which may be justly charged to his his acting the part of Lusignan in Zara for his benefit, two former productions. Here are no extravagant on the sixth instead of the ninth night, to which he was characters nor unnatural situations. On the contrary, only intitled by the custom of the theatre.

an admirable knowledge of life and manners is displayThe Adventures of Roderic Random, published in 1748, ed; and most useful lessons are given applicable to in2 vols Izmo, a book which still continues to bave a most teresting but to very common situations. extensive sale, first established the Doctor's reputation. We know not whether the remark has been made, All the first volume and the beginning of the second ap- but there is certainly a very obvious similitude between pear to consist of real incident and character, though the characters of the three beroes of the Doctor's chief certainly a good deal heightened and disguised. The productions. Roderic Random, Peregrine Pickle, and Judge bis grandfather, Crab and Potion the two apo- Matthew Bramble, are all brothers of the same family. thecaries, and 'Squire Gawky, were characters well The same satirical, cynical disposition, the same geneknown in that part of the kingdom where the scene was tosity and benevolence, are the distinguishing and chalaid. Captains Oakhum and Whiffle, Doctors Mack- racteristical features of all three: but they are far from shane and Morgan, were also said to be real personages; being servile copies or imitations of each other. They but their names we have either never learned or have differ as much as the Ajax, Diomed, and Achilles of now forgotten. A bookbinder and barber long eager- Homer. This was undoubtedly a great effort of gely contended for being shadowed under the name of nius; and the Doctor seems to have described his own Strap. The Doctor seems to have enjoyed a peculiar character at the different stages and situations of his life. felicity in describing sea characters, particularly the Before he took a house at Chelsea, he attempted to officers and sailors of the navy. His Trunnion, Hatch- settle as practitioner of physic at Bath; and with that way, and Pipes, are highly finished originals; but view wrote a treatise on the waters ; but was unsuccess

; what exceeds them all, and perhaps equals any charac- ful, chiefly because he could not render himself agreeter that has yet been painted by the happiest genius of able to the women, whose favour is certainly of great ancient or modern times, is his Lieutenant Bowling. consequence to all candidates for eminence, whether in This is indeed nature itself; original, unique and sui medicine or divinity. This, however, was a little exgeneris.

traordinary; for those who remembered Dr Smollet at By the publication of this work the Doctor had ac- that time, cannot but acknowledge that he was as grace. quired so great a reputation, that henceforth a certain ful and handsome a man as any of the age he lived in ; 3

besides,

a