JOURNAL

OF

THE FRANKLIN INSTITUTE

OF THE

State of Pennsylvania

AND

AMERICAN REPERTORY.

JANUARY, 1846-6

CIVIL ENGINEERING.

Baltimore and Ohio Railroad Company.

We have before us the 19th annual report of the Baltimore and Ohio Railroad Company, in which we find a satisfactory statement if the affairs of the Institution for the fiscal year terminating the 30th September, 1845. This document is lucid and precise, and in exam- ining its contents we have only to regret that it is not accompanied by the very valuable tabular statements which have been appended to the last two reports. We have regarded those tables, in which all ‘le expenditures of the Company were nicely discriminated and walyzed, as among the most valuable contributions to our details of railroad statistics which the experience of the country has yet fur- uished, and we cannot withhold the expression of our disappointment ‘hat they have not been appended to the present interesting report.

The Baltimore and Ohio Railroad Company had the rare fortune io secure in good season the service of an enlightened President to iake the helm of their great enterprize, and the aid of an able Engi- neer to execute measures which were previously well matured. The improving condition of the Company’s affairs, is the happy fruit of this combination of talent. There are few cases in this country in which works of public improvement have exhibited a more steady and healthy advance towards permanent success, than has marked the progress of this enterprize.

Vou. XI, 3ap Serres.—No. 1.—Janvary, 1946. 1

Civil Engineering.

The financial results of the year will be seen by the following ex. tract, which we take from page 5 of the report.

Statement of the Revenue and Expenses of the Baltimore and Ohio Railroad Company, on account of the Main Stem of the road, for the year ending the 30th of September, 1845.

|

‘The amount received for the transportation of Passen-

gers and merchandize for the year ending —

30th, 1845, has been. $738,603 18 And the expenses for the same period have been as fol-

low, viz:— | Expenses of transportation, including fuel,

salaries of superintendent, agents, con- | ductor, &c., &e., ; . $113,285 | Repairs of the road, ; 88,184 |Repairs of depots, . , ; 6,921 Repairs of passenger cars, , 11,229 Repairs of locomotives, , F 44,481 Repairs of burden cars, . R 24,895 | Repairing and rebuilding bridges, ‘ 55,516 2 ‘Repairs of water stations, . 1,525 | Watching bridges and pumping water at / Wate rstations, 8,984 Office and incidental expenses, including

salaries, house rent, fees to counsel, taxes

on property, &e., . ‘ , 8,815 99)

iH D

mm =1 0% 1 &

“1%

Sos ~ & —_—

Making in all ‘ . | 363,841 44

‘Shewing the earnings of the road to be | 374,761 74 |The Dividend of the Main Stem from the | | Washington Branch in April last was 30,978 00)

_And the dividend yetto be received from

the same, . ; 30,978 00

Making . : 61,956 00 The interest on the million loan, &c., 60,931 83!

Leaving

The aggregate revenue for the year is $738,603, which exceeds that of the previous year by the sum of $79,983.

The amount expended for cars, engines, &c., for the accommoda- tion of the coal trade was $118,804, which includes the sum of $35.- 217, disbursed for that purpose the previous year.

The expenses of working the road and keeping it in repair, exhibit but a trifling increase—with the exception of the item of bridges— over those of the previous year, notwithstanding the very material increase of trade and travel which has been accommodated.

ex-

Vhio ad,

The Baltimore and Ohio Railroad Company. 3

The bridge account, however, is upwards of $49,000 greater than that of last year. This serious addition to the expenditures of the year is attributed to the necessity in which the Company was placed, of having all the bridges refitted and strengthened, so as to be made capable of sustaining the weight of the heavy trains which it has been found expedient to run. This is no doubt a wise precaution, for these structures were not originally intended to sustain machines of 22 tons weight, drawing trains of 6 tons coal cars, and were found unequal tosuch duty. We trust that further experience may not show that the track itself—even that portion west of Harper’s Ferry—is also inadequate for this service.

The report holds out that the year’s experience in the transpor- tation of coal has gone to demonstrate the sufficiency of the estimates of the Company’s engineers on this head ; but though they are looking forward to a considerable increase of this trade, it does not appear that they have yet carried a sufficient quantity to justify the drawing of any useful practical conclusions from their own experience. We would rather rely on the speculative estimates of their judicious offi- cers than on the meagre experience which they have obtained in run- ning ueW machinery for a few months over a new track.

The President anticipates a coal trade, within a year or two, of

100,000 tons, or upwards—and, in our view, they must carry this amount for several years before we can set much value on their ex- perience. The report concludes with a repetition of the difficulties which are found to embarrass the contemplated extension of the road to the Ohio river—difficulties resulting from the onerous restrictions imposed by the Legislature of Virginia in the act authorizing the Company (o terminate their line at Wheeling, and the refusal of the Legislature of Pennsylvania to permit them to terminate it at Pittsburgh. In re- gard to both these States, however, it informs the stockholders that there will be made “renewed and vigorous efforts for that purpose at the next session of their respective Legislatures.”

We add the following interesting table, which presents a condensed view of the results of this Company’s operations from the beginning.

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Description of the Great Britain Iron Steam Ship, with Screw Pro- peller; with an Mtecount of the Trial Voyages. By Tuomas Ricnarp Guppy, Esq., C. E.

(From the Proceedings of the Institution of Civil Engineers.) (Continued from vol. x, page 366.)

Mr. Barnes confirmed the general statement of the results of the trial of the screw, which was lent to the ‘ Napoleon,’ the information having been, in fact, communicated by him to Mr. Guppy, immedi- ately after trying the experiments. One point only required correc- tion. ‘The reason for the whole pressure of the steam not being ap- plied was not from a fear of breaking the screw, but because of its small dimensions, it having been made for the ‘.@rchimedes,’ whose engines were SO or 90 h. p., and more particularly on account of the pitch being so small. The result was, that when it was applied on board the ‘ Napoleon,’ the engines (which were 130 h. p.,) would have required to have been driven at such an increased number of strokes, that the boilers could not have supplied sufficient steam. Even with the throttle valve partially closed, great attention was required to keep up a steady speed.

He thought the results obtained, with such a small propeller, quite extraordinary, and such as could not have been anticipated.

He had since calculated the results more accurately, and found them as shown in the following table :—

Kevolutions Speed First | Second per in |

minute. knots. Mean. Mean.

|

| 9-9835 | 10-0875 10-1835

10-031 10-132

Mean 32° + . | 100815

| | |

J

The speed of the screw of 7 feet 74 inches pitch was 10-7165 knots, which was in the ratio of 0-9047 to 1.

In his original calculations, given to Mr. Guppy, he has erroneously assumed the pitch of the screw to have been 8 feet. The results of the indicator were 10°15 lbs. per sq. inch. Veducting for friction, and more ample allow-

ance than was required for engines in good

order, which was not, perhaps, too much for

engines which were quite new, and of which

1!| the movements were stiff,

Remains, 8-60 = 95:5 h. p. for -_—— each engine. 1*

Civil Engineering.

Mr. T. R. Guppy stated, in answer to questions from the president and members, that during the whole voyage the throttle-valve was only one-third open, and that the steam was cut off at one-sixth ot the stroke. It was not possible to take any accurate account of the coals consumed, but he estimated the consumption at about 40 tons in 24 hours. The screw propeller of the Great Britain was too small, but still the speed obtained even against a heavy head sea, was never below 53 knots per hour.

Captain Hosken said, he considered it necessary to reduce the speed in heavy weather; it was in such cases dangerous to apply all th: power of the engines; there was a danger of the sea making a clear breach over the vessel if she was driven bodily forward, instead of being allowed to rise with the waves. The experience he had ac- quired in the Great Western had clearly proved the correctness of his views.

His opinion of the advantage of the screw as a mode of propulsion was decided, and he thought that it would, for sea-going vessels, su- persede paddle-wheels. During the worst part of the voyage, with the Great Britain, the screw was never more than one-half of its di- ameter out of the water, and the other half was acting efficiently at the same time; whereas under similar circumstances, with such a cross sea, the leeward paddle-wheel would have been immersed, pro- bably above its shaft, while the windward wheel would have been completely out of the water; the strain upon the engines, in such a ease, was very prejudicial ; but in the Great Britain he never noticed any variation in the working of the engines, not even when she was struck with the heavy sea which had injured the bow.

Captain Sir Charles Napier inquired, whether the Greaf Britain steered well, and whether it was not found she had a tendeney to fall off to leeward in a cross sea? He should have supposed that the ac- tion of the screw propeller being so entirely in the stern, it would act upon the ship like seulling a boat.

Captain Hosixen replied, that the Great Britain steered extremel|s well; aud that there was not any tendency to fall off to leeward.

The action of the serew could not be correctly compared with that of a seull upon a boat; in that case, the power acted entirely upon the stern; but with the screw, the power was exerted in the direction of the shaft, up to the engines, in the centre of the ship, and by a sim- ple arrangement it could be carried on even upto the bow. He was of opinion that the leeward paddle-wheel had not much power to keep a vesse! up to the wind ; it was so close to the ship’s side that its le- verage was not considerable.

Sir Charles Napier thought the principal danger of the screw pro- peller was in running before the wind in a heavy sea. If struck by a heavy wave, the sternpost and the propeller might be carried away together; as also in case of getting on shore, the screw would not be so efficient in clawing off shore as the paddle-wheels would be.

Captain Hosken said it was evident that the propeller was not easily injured, for since his arrival in the Thames he had found, coiled round

Description of the Great Britain Iron Steam Ship. 7

the shaft, nearly 9 fathoms of chain cable, which had been apparently torn away from the mooring of a buoy, in coming up the river.

Mr. J. Miller said, one point of importance in favor of the screw was its not being affected by variations of immersion, arising either from the draught of water of the vessel, or from the rolliug ina heavy sea. He had noticed particularly the difference of the speed of the engines, on board the Royal Mail Company’s vessels, at the com- mencement and at the end of a voyage. At starting, with a full com- plement of fuel, the paddle-wheels were plunged so deep, that the speed of the engines, which ought on an average, to be 17 strokes per minute, was reduced to 8 or 9 strokes, and at the end of the voy- age the paddle floats had scarcely sufficient hold on the water. A ves- sel with a screw propeller would not be so affected.

He thought also, that the screw was less liable than paddle-wheels to be injured by heavy seas.

Captain Hosken was anxious to record clearly the points where he was satisfied the propeller was preferable to the paddle wheel for steamers generally, but more particularly for the purposes of war and for Atlantic navigation.

By using the screw, a great weight was entirely removed from the top, sides and centre of the ship.

The exertion of the power of the engines was transferred from the top, sides and centre to the lower midship body, which was the strong- est part of the ship.

There was a saving of nearly one-half the weight. In the instance of the Great Britain, that ship was first intended for paddle-wheels, which with all the appurtenances of beams, boxes, shafis, &c., were estimated at 180 tons. The weight of the propeller, cliain-wheels, shaft, chain, &c., might be taken at about 80 tons, and that weight was dispersed over nearly half the ship’s length. When leaving port and the ship was deep, the propeller would exert its greatest power, when it was most required; paddle-wheels, on the coutrary, when deeply immersed, would not allow the engines to exert their power.

A steam ship, with a propeller, answered the helm quicker, and steered easier, than a paddle-wheel ship.

A great point, also, was the superior efficiency of a screw propeller ship under canvas, on account of the absence of the unsightly and det- rimental paddle-boxes ; possessing also the advantage of the sails act- ing with the engines, instead of injuriously to them, as with paddle- wheels. When the sails took effect, the ship heeled, or inclined to one side, the paddle-wheels consequently became too deeply immersed on one side, and had not sufficient hold upon the water on the other, manifestly wasting the power of the engines.

The screw propeller was more easily disconnected from the engines ihan the paddle-wheels, should it be required to save fuel, or if the engines were disabled, and the ship being properly rigged, a decidedly efficient sailing ship still remained, which in a paddle-wheel ship was not possible.

The screw propeller was less liable to be damaged by héavy seas, or by shot, than paddle-wheels. Very recently, the West india Royal

8 Civil Engineering.

Mail Steam-packet Dee had one wheel quite disabled, by a heavy sea striking it; while the screw was nearly always so immersed as to be out of the reach of injury, either from waves or shot.

As the relative merits of screw propellers and paddle-wheels were of national importance, Captain Hosken felt confident no apology was necessary, for thus, as concisely as possible, giving his opinion before the institution.

If he might recommend any point for the consideration of the mem- bers, it would be that they should exert their ingenuity to discover the best propeller, all circumstances being considered ; as in his opin- ion it would be very difficult, if not impossible, to find a propeller that should be the best under every variety of circumstance. He considered the best method would be to multiply or reduce the speed of the propeller, as might be found necessary under different cireum- stances, but that, he was aware, would, in very large steamers, be difficult of attainment.

Sir Charles Napier agreed with Mr. Miller with regard to the dis- advantages of the deep immersion of the paddles, particularly those of war steamers, where wheels were constantly plunged too deeply when they had their full armament and fuel on board. For fifteen years past he had urged upon the Government the necessity of paying more attention to the construction of their war steamers ; for, in his Opinion, there was not one really good steamer in the service; and he thought the Retribution, which was the last vessel finished, was not any improvement upon its predecessors. He objected particularly to the present construction of direct-acting engines, by which the work- ing parts were exposed to injury from shot. He thought, that all the upper parts of the engines, and the naves of the paddle-wheels, should be made of wrought-iron, as in the case of being struck by shot, less serious injury would ensue than when they were made of cast-iron.

He would suggest, also, whether it would not be possible to have tanks near the paddle-boxes, to be filled with water as the fuel was reduced in weight, and thus to keep the vessel at a uniform draught, so that the power of the engines could be always advantageously em- ployed.

Captain Hosken said, in reference to the points suggested by Sir Charles Napier, experience had shown that any thing cumbersome about paddle-wheels was bad for sea purposes, any machinery about them was difficult to be kept in order, and if the paddle-wheels were made to reef, when they were exposed to a heavy gale, or sea, they would assuredly lose a large portion of their paddie-floats.

The suggestion of a contrivance to fill water about the paddle- boxes, in proportion to the fuel consumed, so as to keep an uniform dip of float-board, appeared not only objectionable, but it amounted almost to an impossibility. It was searcely possible, even if desirable, to find space for 500 tons of water in a steam ship that might take that quantity of fuel as her sea-stock ; and doing so, would keep the ship in a long voyage continually groaning under a heavy burthen. He agreed with Sir Charles Napier as to the desirableness of an unl- form dip of the paddle-board if it could be obtained ; but if it was only

Description of the Great Britain Iron Steam Ship. 9

to be arrived at by always carrying a heavy weight, it was better to continue the present plan, of starting deep and arriving light.

Mr. Guppy said, in answer to questions from members, that, at present, he believed the average speed obtained by vessels with screw propellers, was below that of paddle-wheel steamers. A new screw of larger diameter and greater area of palms, was being made for the Great Britain, with a view to increasing the speed.

It should not be forgotten, in the discussion, that a distinctive fea- ture of iron vessels was their stiffness, and he conceived they were hetter calculated to withstand the shock of heavy seas than wooden vessels were.

Four chains, weighing together about seven tons, were employed for communicating the power from the upper drum, upon the main shaft, to the lower drum upon the shaft of the propeller. They worked smoothly and without noise, and at present had not shown any tendency to wear, or to lengthen. From the form of the link, he conceived that the chains would only lengthen on the slack side, un- der any circumstances; and this would not affect their working, as the projecting ends of the links would, on the driving side, always fall into the recesses prepared for them, so that these recesses must be much worn, before the chains would ride out of their proper direction upon the drums.

Mr. R. Stephenson observed, that the chains very nearly resembled those used in the early locomotive engines, and which were discarded on account of lengthening so much asto render them useless. It was true, that the links of the locomotive chains were much smaller, there were many more traversing pins, and the speed at which they trav- eled was probably greater than the large driving chains of the Great Britain, which would, therefore, be less liable to injury than those he had mentioned.

Sir John Rennie, President, said that the Institution was much in- debted to Mr. Guppy for the paper which had induced, in the course of the discussion, the expression of the opinions of the good authori- ties who had spoken on a subject of such great importance.

The advances made in steam navigation were already very great, but he anticipated much greater would result from the application of the screw propeller. The best forms, not only of propellers, but of the vessels to which they could be most advantageously applied, would be more accurately ascertained from the experiments now in pro- gress, by the order of the Government, and also by private individ- uals; he hoped the Institution would soon be put in possession of the result of these, by the same spirit of liberality as had induced Mr. Guppy to present his paper.

A very interesting communication might be produced, by tracing the progress of steam navigation for the last few years, taking, for instauce, one station, that of Dover, where, it would be recollected, with the old vessels eight or nine knots an hour was considered a good speed, but at present, with better shaped vessels and more pow- erful engines, a speed of nearly 15 knots per hour was stated to have been attained.

10 Civil Engineering.

Mr. P. Taylor said, that great difference of opinion existed among the officers of the French navy as to the capabilities of the Napoleon. It had been asserted that with the peculiar build and great proportion of power to tonnage of that vessel, greater speed should have been attained. Mr. Taylor was not of that opinion, although he fully ap- preciated the build of M. Normand’s vessel, and the excellence oj Mr. Barnes’ engines. He had paid much attention to the result of the voyages of the Napoleon, and found them, on an average, more rapid than those of the paddle-wheel vessels on the same station. ‘The screw did not generally make such good headway in smooth water; but with a sea or wind sufficient to lay a paddle-wheel ship at all over, the screw gained immensely, and hence its average superiority.

After the trial voyages and the run from Havre to Marseilles, with the cast-iron screw, which had been mentioned at the Institution ona previous occasion, it was found, on putting the Napo/eon into the graving dock at Toulon, that the outer journal of the propeller-shaft was much worn, and that the cast-iron screw was much affected by galvanic action; a new bronze screw was therefore cast, and was highly polished and varnished before it was fixed. At the same time the bearing areas of both the outer and the inner journals of the shatt were increased, and a jet of cold water was arranged so as to be con- stantly applied to them. Since these alterations, there had not been any undue wearing of the journals.

Mr. Barnes would not venture to state the relation of power to tonnage on board tac Napoleon, as the methods of measurement of vessels were quite illusory. The engines were 130 h. p. ‘The vesse was 148 feet 6 inches long, and 27 feet 4 inches broad at the water line, drawing 11 feet 10 inches aft, and 7 feet 5 inches forward, and the area of the midship section at that draught was 144 square feet. By the ordinary rules of measurement, the tonnage would be 490 tons, and the displacement 365 tons.

He had made many engines for vessels built by M. Normand. aud he knew their capabilities. He was of opinion, that if the feathering paddle-wheels, invented by M. Cavé, had been adapted to the Napo- leon, as good speed would have been attained, as with the screw, in all weathers; but that with the common paddle-wheels such results could not have been arrived at.

Mr. F. P. Smith had found, with reference to the journals of the propeller-shaft, that steel was the best material for the bearing of the toe or extreme end, where the destruction was most rapid, and that the best form was that of two hemispheres, working under a constant jet of cold water. The experience upon the Rattler tended to show, that it was advantageous to reduce the bearings as much as possible; for they had always worn down to certain dimensions, and then had ceased to wear. On the contrary, however, on board the Great Bri- tain and the Napoleon, it appeared, that an increase of the size of the journals had been advantageous. On this practical question, the man- ner in which the thrust of the propeller-shafts was received in the toe bearing must be well considered, before any rule could be laid down.

As liad been previously stated, one of the chief merits of the screw

Description of the Great Britain Iron Steam Ship. 11

was its permitting such an advantageous use of the sails. In the Rattler it was found, that when with steam alone the vessel was running 94 knots to 94 knots per hour, and the engines were making 26 to 263 strokes per minute, on the sails being set the speed increased to 12 knots, and the engines made freely 284 strokes. At that rate it was supposed the screw was dragged through the water; but on applying the dynamometer it was found, that the forward thrust of the shaft was the same as before the sails were used. The screw was, there- fore, producing its full effect. Ifthe sails had been set on a paddle- wheel vessel, under similar circumstances, the lee wheel would have been so much depressed as to have impeded the progress; and the windward wheel would have lost a considerable portion of its effect, owing to the heeling of the vessel. ‘To that cause must be attributed the fact of the Royal yacht gaining speed in proportion as it short- ened sail, with the wind on the beam.

In the recent trial cruise, while rounding the Longships against a heavy head sea, the Rattler did not make good way. The vessel pitched so, that the propeller was frequently more than half its diame- ter out of the water. On trying the dynamometric effect, it was as- certained that the power was fully expended, but that it was insuffi- cient for the tonnage of the vessel, whose build also was not calculated for speed. In rough weather, with a head wind, the rigging was a serious impediment to speed, but with the wind a little abaft the beam, it was thought that, in spite of her build, the Rattler would prove herself fully equal to any vessel of similar power and tonnage.

From his previous experience of the performances of the Ratéler i!) smooth water, Mr. Smith had recommended to the Admiralty that a larger propeller should be tried. The recent trials at sea had proved the correctness of the recommendation, which was now being acted upon.

Captain Crispin corroborated Mr. Smith’s statement, relative to the Royal yacht. With the wind on the beam, owing to her heeling over, the lee wheel was so much plunged as to materially reduce the speed of the engines and of the vessel, and the more the sails were reduced, so as to bring her upon an even keel, the faster she overhauled the Rattler, whose engine power he considered insufficient for the ton- nage; whilst the superior size and power of the yacht enabled her to make good way against a heavy head sea. The performance of the Rattler, with the wind on the beam, and the canvas set, surprised all te officers of the squadron.

To be Continued.

Civil Engineering.

Atmospheric and Rope Traction Railways. Mr. P. Barlow’s Experiments comparing the Power Lost.

Tage, showing a Comparison of the Useful Mechanical Effect of the Dalkey Engine, as applied by the Atmospheric pipe, with that of the Tyler Hill Engine on the Canterbury and Whitstable Railway, as appt by the ses.

. | No.of] Experiment

2 | Vacuum.

#2 | Weight of Train.

‘auisuryy Aax| eq

Horse power indi-| cated during Ex- periments.

Average velocity)

per hour. |

“Average velocity | per minute.

Resistance due to

Friction and Gravity. = Usetul Mechanica}

6211 PSOl £201

3. Le

at

Effect.

£88

62 L.FE 32 0.08

GLO.LE

08! power pr cent! = ~/

ments.

~ oO =) G2 -) = — 2 =) — — — > + 4 “— s a — _ cd 2

Ont ‘On On “ONT

ta | Author of Experi- | |

.o. of Experiment

| N £3 | Weight of Train

= |

» |

Te youy am ) peejsul » sl au'y AWS puR

ay) wlody

‘saputfAg aursary [tp 4ajAy,

Horse Power indi- cated during ex- periment.

Average Velocity per Hour.

| Average Velocity

|

“GAIN.

Uoljatyy ay Joy uo, aad ‘sq] Eg sm

lod S.UIN *H [Blo saumuio,) Gz. ‘

: HOUT SUIR-C 0%

per minute.

“HOTPOLY aq) 107 ape Ueaq sey 2

uononpap ou aui’y aqeisity Ay 841 uO aulzua |

ay) jo Jamod oy) Buleuinsea uj—'(2) aon

Resistance due to Friction and Gravity. Useful mechanica! Effect.

| Lost power p. cent

C60! sq]

a4 0aj8 109) G

‘SET UL T JO JUaIpRss jenjow agi | ‘C{] Ul T Jo auljoul Ue 407 payepnoyt “OHI, O} BNP BUR sISe1 BY T—"(1) BION

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d

It will be seen by this table that the loss of power by Rope traction varies from twenty to fifty-one per cent., and by Atmospheric traction seventy-six to eighty-five per cent. Civ. Eng. & Arch. Jour

13

Sufety Coupling-box for Railway Trains.

The occurrence of serious accidents on railways, arising from the engine running off the line, renders it desirable that some simple means should be de ‘vised for inst antly disconnecting the engine and tender from the train, when such an occurrence takes place. The late acci- dent on the Edinburgh and Glasgow railway, arising from the engine leaving the line, and attended with the loss of one life, though one too many for humanity to spare, might have been much more disastrous, had not the coupling irons given way, connecting the train with the tender. ‘The train was thus allowed to remain on the rails; and what we would suggest is, that that which took place by a happy accident should in future be insured, by a simple self-acting mechanical con- trivanee, Which shall unlock the train from the engine the moment that the latter shall happen to leave the rails. A scheme of this kind was devised by Mr. 8. B. Howlett, of the Ordnance Office, so early as $40, and was deseribed and illustrated in the fourth volume of the Professional Papers of the Royal Engineers. We take the liberty of e-producing this plan, as it appears to be simple, and promises to be efficient.

rig. 1, A east-iron box, shown in plan, consisting of sides and bot- mM ; i : top, consisting of a separate plate bolted to the box, being

emoved to show the arrangement of the parts in the interior. Ex- ernally, it is provided with trunnions which turn in sockets bolted to ‘he front of the carriage. The draw-bar which proceeds from it is ‘onnected by short link-work to the tender.

Fig. 2. A longitudinal section of the box through the middle of fig. |, showing one of the sockets behind.

Fig. 3. A side-view of the draw-bar detached.

Fig. 4. A representation of the position of the draw-bar when the Vou. XI, 3np Sertes.—No. 1.—Janvary, 1846. 2

14 Civil Engineering.

chain is pulled sidewise: in this position the bar can be drawn ou with ease, and the connexion thus broken.

sate Fig. 5. An isometrical sketch oj the coupling-box, supposed to be fixed on the front or lower part ot the luggage truck or first carriage; or it might be fixed underneath, the construction being adapted fo; either position. The end of th draw-bar is broken off in the figure for want of room. ;

Literal References.—a, is thy boss or projection cast on the sol of the box, the use of which: is to afford a holding surface to the end of the draw-bar.

b, 6, springs riveted at one end to the walls of the box, near th opening in front; they reach be- yond the boss a, and embrace th end of the draw-bar, (when engaged with the boss) the object of which is to retain it exactly in its place.

c, ¢, the trunnions, cast one on each side of the box, upon whic! the box turns as on hinges,

d, one of the sockets, of which there are two, in which the trun nions turn ; the sockets are bolted to the carriage.

e, the draw-bar, formed on its under side with a notch, which sii; over the boss a, when the bar is introduced into its place, and is he in that position by the springs.

It is obvious that no direct pull could withdraw the bar, becaus the notch rests over the boss, and the bar being held by the springs, cannot shift its position laterally without a greater lateral force being applied than could occur by shaking while traveling. The oilice | the springs is simply to hold the bar over the centre of the boss, and should, in the manufacture, be adjusted accordingly; they should, 1 iact, be of such strength that a man laying hold of the end of th bar and pulling it as a lever against either side of the entrance, shou be just able to open either of the springs and release the bar. Th entrance of the box is wider than the bar, sufficiently to allow for o1- dinary deviations from the middle position.

Mr. Howlett proposes the application of this safety-coupling be- tween the tender and the first wagon of the train. We think, how- ever, that it might be applied between the engine and the tender, so as to leave the tender, as well as the train, on the line. Our princi- pal object in proposing this is to provide likewise for the safety of the driver and stoker on the platform. A simple modification of the ex- isting arrangement of the platform would, however, be necessary to effect this most desirable end: for, according to the presently arranged method, one-half of the platform is erected on the engine, the othe!

Address by Prof. Frazer. 15

half on the tender. Now, as the engine and tender are constantly linked together as one, we see no difficulty in the way of attaching the whole of the platform to the tender-frame. Thus, while the men could have a comple te command over the engine, they would be in- dependent of it for foot-hold; and if it ever started aside and left the te ois r and train, it would go alone to destruction. We do not forget that anothe r connexion subsists between the engine and tender, namely, the flexible tubes which convey the water from the tender to he ri e-pumps. These would, however, very easily give way if no ther connexion remained. But, at all events, it would not be a diffi- cult matter to construct the water-tubes with sliding joints, which iid part asunder of their own accord when the engine leaves the

ler. The railing with which the platform is enclosed at the sides

be carried round the front of it close to the engine, leaving an

ning, of course, for firing; this would prevent the possibility of the ver or stoker being precipitated from the platform at the moment

» accident. The application of Mr. Howlett’s coupling-box would, in this ease, likely require it to undergo some modification. We recommend the principle of the complete isolation of the engine to the consideration of railway engineers, who will best understand the value of what we have now stated. The utility of the idea, apart from the readiness with which it might be applied, is as clear as dis- astrous occurrences can make it, when we know that these occur-

rences would have been greatly alleviated had the arrangements

which we propose been applied. At the time of the accident on the

Edinburgh and Glasgow line, the train was running, it seems, at the e of 60 miles an hour: a very high speed on the narrow gage. ile we would hail with pleasure the progress of steam-locomotion,

: would also insist on the corresponding advance of precautionary measures against accident, and would aid in the furtherance of this

as far as our humble suggestions can go. Glasgow Prac. Mec. & Eng. Mag

FRANKLIN INSTITUTE.

iddress delivered by Proressor Frazer, at the close of the Fifteenth Exhibition of American Manufactures, held by the Franklin In- stitute of the State of Pennsylvania, for the promotion of the Mechanic rts, October, 1845.

LADIES AND GenTLEMEN :—The fifteenth exhibition of American Manutactures held by the Franklin Institute, is now about to close, aud while the members of the Institute congratulate each other upon the success which has attended their labors, it is natural that they should have something to say in reference to it, to those who have favored them with their attendance.

[need not tell you that the exhibition has been a successful one, nor endeavor to show in what its superiority consists. That it is su-

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16 Franklin Institute.

perior to former ones, is a matter of course; the very end and aim o;

holding them at all, is to encourage those improvements of which our

arts are susceptible, by showing to the public as well as to the manu. facturers themselves, what has been done, and by suggesting to them that which still remains to be done, in their respective branches. [tf]

did not feel that this end had been attained, and that its attainment

had been shown by the decided superiority of this over former exh. bitions, | would not have the courage to say one word to you upon the subject; nor the faith to look forward hopefully to a similar im. provement in the next, and so on for an unlimited series, until the whole of our arts have obtained the perfection which it is possible fo them to reach. I cannot ask you to go back to the first of these ey. hibitions, held in 1824, (when eleven medals were awarded.) for my own recollections will not carry me back that far, but I ask you 4 task your memories, to say whether within the last three or for years only, the improvement in American manufactures has not bee such as to astonish the most credulous, and to justily the hopes of th most sanguine. How many impossibilities in manufactures have bee accomplished in that time? Itis true that exhibitions of this kin are not the only causes of this improvement—but that they exercis a very great influence in promoting this result, who can doubt? Th fact of their adoption by sister institutions in the cities of our own country, and the encouragement of them by the various government of Europe, is a suflicient evidence of their usefulness. You have a felt their utility in the astonishment with which you have examin: some of the products now spread upon our tables; products whic! you were made aware for the first time, could be produced in suel perfection by our own manufacturers. They operate usefully by in- forming the community what they can expect from our own industry, and thus tend to check that prejudice which still exists, though in far less degree than formerly, against domestic manufactures, at which compels our manufacturers to the vicious practice of stamping