tained by strengthening these points by increase of their convexity and thickness; and where the workman would support the angles by braces, there are ridges of bone in the calvaria, or roof of the skull.

If a stone arch fall it must give way in two places at the same time; the centre cannot sink unless that part of the arch which springs from the pier yields; and in all arches, from the imperfect Roman arch to that built upon modern principles, the aim of the architect is to give security to this point.

In the Roman bridges still entire, the arch rises high, with little inclination at the lower part; and in bridges of a more modern date, we see a mass of masonry erected on the

pier, sometimes assuming the form of ornament, sometimes of a tower or gateway, but obviously intended at the same time, by the perpendicular load, to resist the horizontal pressure of the arch. If this be omitted in more modern buildings, it is supplied by a finer art, which gives security to the masonry of the pier, (to borrow the terms of ana. tomy,) by its internal structure.

In what is termed Gothic architecture, we see a flying buttress springing from the outer wall, carried over the roof of the aisle, and abutting against the wall of the upper part, or clere-story. From the upright part of this masonry, a pinnacle is raised, which at first appears to be a mere ornament, but which is necessary, by its perpendicular weight, to counteract the horizontal thrust of the arch.

Improved Straw and Hay Cutting Machine. [From the Edinburgh Quarterly Journal of Agriculture.]

The annexed cut exhibits one of these im. proved machines, as manufactured by Messrs. Slight and Lillie, with the framing made entirely of cast iron. A is the feeding-trough, the rollers being only partially seen. B is the nozzle or cutting-box. C C, the cutter-bearers, with the cutters attached by their bolts. D is a lever and weight, which, through the medium of the bridge E, keeps a constant pressure on the feeding-rollers, to counteract any inequality of feeding. F is the fly-wheel for equalizing the motion; and G, the handle to which the power is applied. The small pinion on the fly. wheel shaft gives motion to the spur-wheel, which is mounted on the shaft of the lower feed. ing-roller, and carries also the lower feeding. pinion. This last pinion works into the pinion of the upper roller, and both being furnished with very long teeth, they thereby admit of a limited range of distance between the rollers, according to the quantity of feed.

With one of these machines, a man, assisted by a boy to feed in the hay or straw, can cut at

the rate of eight stones per hour; and that quantity of cut hay is found to be sufficient for sixteen horses for twenty-four hours.

The machine, of which the above is a figure and description, combines, in an eminent de. gree, expedition and efficiency, with ease to the workman. We do not think it can be made of a simpler construction.

Manufacture of Silk-Reeling, Twisting from the Cocoon-Description and Drawing of Brooks' Silk Machine. [From the New. York Farmer.]

The manufacture of silk is so likely to become an important branch of national industry, that we deem it important to lay before our readers all the information that we can obtain.

On the present occasion, we shall simply state the particulars of an experiment with Mr. Adam Brooks' machine.

After considerable inquiry for cocoons in this section of the country, we were enabled to obtain a bushel that had been, two years ago, sent on to this city, from one of the Southern States, for a market. In consequence of there being no demand for them, they had been put aside as a

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worthless article. They were in a box rendered tight by paper pasted over the openings at the joinings of the boards. Some of the cocoons were perforated by an insect not unlike the common moth; but generally they were in excellent order.

All the practical information we had had, was from seeing Mr. Brooks exhibit his machine in operation a few times. In connection with another person, whose opportunities of practical knowledge were no greater than our own, we took a peck of the cocoons, 485 in number, and weighing ten ounces. Without assorting them, as we should have done, we put a handful of some 20 or 40 into water about boiling hot-took a small broom and pressed them into the water-found the floss silk adhering to the broom-gathered the silk from the broom, and kept drawing the silk until a fibre ran off singly and evenly from each cocoon-lifted these running cocoons from the water with an instrument not half so convenient as a skimmer, and placed them in a winding basin partly filled with heated water-served other cocoons in the same manner until we acquired two threads of about 100 fibres or cocoons, and carried the threads through the guide wires, between the rollers, to the bobbins. Thus prepared, we began to wind by turning the wheel, keeping

up the thickness of the thread by supplying additional cocoons, and collecting and attaching the ends of those that had broken. After a sufficient quantity was on the bobbins, took them and placed them in the upright posts, and carried the ends through the guides and rollers to the bobbin, for the purpose of doubling and twisting. Replacing the bobbins with two more, we then, by turning the wheel, wound, doubled, and twisted the silk at one operation. Thus continuing, we obtained from the peck 14 ounces of fine sewing silk, which, when deprived of the gum, by being several times boiled in soap suds, weighed one ounce. Besides this, there were 4 ounces of floss silk obtained from the gathering of the silk from the broom, from cocoons that would not wind, and from those that had been injured by insects, or im perfectly formed. These 4 ounces, after having been cleansed in soap suds, weighed 3 ounces. This floss silk is to be carded and spun for stockings and other purposes.

The sewing silk being very fine, did not, owing to the improper adjustment of the machine, give a sufficient twist; in other respects it was pronounced a fair, saleable article. When it is considered that we were entirely green at the business, were several times obliged, as soon as we got into operation, to omit our labors for

Witness again took charge of the engine on the trip previous to. that on which the accident occurred, in consequence of the illness of Mr. Potter. Witness was employed as engineer of a steamboat at the South, 12 years ago, which boat was run by him during the season of navigation. Says that his management on the night of the accident was not at any time influenced by a desire to shorten the passage. Heard no inquiry made by any of the passengers about racing. The only fuel used by him in the NewEngland was pine wood. Witness has been 20 years engaged in his present business. Has served a regular apprenticeship in the manufacture of engines. Has been employed in New-York by Mr. M'Queen, Mr. Allaire, Mr. Sabbatton, and the West-Point Foundry Association.

The safety valve of the New-England was loaded 18 pounds in the square inch, and its position on the steam pipe is 20 feet, or more, from the boilers. Besides two regular weights on the safety valve, there were two extra weights, a 50, and a 28. The valve will blow off at 8 pounds to the square inch, with the two regular weights. This is owing to the lever of the safety valve having been shortened about 2 feet, to bring it within the walls of the room by which it is enclosed. The diameter of the safety valve is 10 inches. The diameter of the steam pipes which lead from the boiler is about 10 inches.

Robert Younger, Assistant Engineer.-Witness started from New-York at a few minutes past 4 o'clock P. M., as assistant to Marshall. At 7 P. M., Marshall left the engine in charge of witness. About half past 8, Capt. Waterman came to the engine-room and asked if the engine did not labor too much in the sea. Also inquired the height of the steam-gauge; was answered 10 inches. Capt. Waterman requested him not to carry any more. Witness then blew off steam, and went to the fire-room and gave directions for less fire. Run with steam from 8 to 10 inches, till Mr. Marshall came on deck at 10 o'clock. Witness examined the water in the boilers frequently on the passage. Did not see the height of the steam-gauge for the last 10 or 15 minutes previous to the explosion, because his view of the gauge while standing at his post in the engine-room was obstructed by an appendage to the steam-pipe. There was no difficulty occurred in the management of the water in the boilers. One of the boilers foamed once while Mr. Marshall was below. This was immediately stopped by putting oil into the force pump. The steam was blown off at Saybrook while lying to for the purpose of loosening the binders of the lifting rods. This was before landing at Saybrook Point. The position of the bulk-head

Witness saw the moveable part of the bulkhead in its proper place on the morning after the accident. Is certain of this from his own personal examination. Has never witnessed an accident of this kind before. Has been 12 years engaged in the business of making en gines. Made his first trip as an acting engineer in the New-England when the boat was first started. Assisted Marshall in fitting up the engine. Thinks that there was no want of water above the flues, but is of opinion that the steam had blown the water from the legs of the boilers.

William Vail, Pilot.-Says that the New-England left New-York at 12 minutes past 4 P. M. in company with the steamboat General Jackson. The steamboat_Boston_left_the_wharf soon after the New-England. The Boston gained upon the New-England till they reached Hurlgate. The New-England then got more steam on, and drew away from the Boston. Found a heavy sea in the Sound, after passing Sands' Point, and the Boston then preserved her distance. The New-England steers very badly. After passing Falkner's Island, the wheelrope got foul, and detained us a few minutes, and the boat fell into the trough of the sea. Off Killingworth, and again off Duck Island, the same detention occurred. When off Cornfield Point, (Saybrook,) witness told the engineer that the boat would not steer in the dark with such a heavy sea, and told him not to carry over seven inches, and repeated the same direction to the engineer when in the river. When crossing the bar at the mouth of Connecticut river, the boat steered very bad, and was obliged to ring the bell to shut off the steam. Missed the dock twice at Saybrook, in consequence of no person being on the dock to take a line. Backed down to near the Fort, where, owing to some difficulty with the valves, the boat could not be started ahead, and was obliged to anchor to prevent drifting on shore. Went into the engine-room and waited twenty minutes for the engineer to get ready for a start. Looked into the fire-room and asked if the water was plenty in the boilers, and was answered yes. Got up the anchor and landed at Saybrook. Started again from Saybrook, and was obliged again to order the steam shut off, because it was difficult to steer the boat. Landed at Lyme, and on starting again, found that the boat jumped so with a head of steam, and steered so badly, that it was necessary to shut off the steam again, and continued shut off till we reached Essex, seven miles from Saybrook. Was detained three or four minutes in landing at Essex. When the small boat had landed, Capt. Waterman gave the word, and witness rung the bell to start the engine, and the explosion immediately followed.

The steam was not blown off at Essex. Witness thought at the time that there was too much steam on. Heard but one explosion, which was like a heavy fall or crash. Had been pilot of the New-England for 30 days, which was nearly as long as the boat had run.

The accident occurred an instant after ringing the bell to go ahead. Witness had felt apprehensions for his personal safety, on account of the pressure of steam which was carried; judged of this by the motion of the engine and the management of the boat. Saw at Saybrook the steam-gauge standing at 12 or 14 inches, and cautioned the fireman against carrying too much steam. The stop at Essex was no longer than 3 or 4 minutes.

The greatest distance gained of the Boston was about two miles and a half, which was near the head of the Sound. The Boston was nearly abreast when we entered the river. Witness is unable to make up his mind as to the cause of the accident, but thinks that the rent commenced in the legs of the boiler near the after end.

Giles Farnham, Fireman.-This witness was on duty at the larboard boiler. Took the first watch from New-York, and went below at 8 o'clock. Took his second watch after 12 o'clock, just before the boat entered the river. There were but 8 or 10 inches steam on the boiler before the boat arrived at Saybrook. The steam-gauge rose to 12 or 13 inches while lying at anchor at that place. Blew off the steam to 7 inches, and pumped water by hand into the larboard boiler. Witness says the water was lower in the boiler at this time than at any other, being at the 2d cock. The other boiler needed no supply. Witness examined the water every five minutes. Started from Saybrook with water at three cocks, and kept it afterwards at four cocks till the time of the accident. Above Lyme there was more steam on than there ought to be for the river. The floating stick in the steam-gauge in the larboard furnace was within two inches of the upper or boiler deck, when the boat stopped at Essex, and witness supposes it must have reached the deck previous to the accident.

While the boat was stopped at Essex, tried the water-cocks, and found the water as high as the upper cock. The witness then went over to the starboard fire-room, and told Bell, the other fireman on duty, that "he would not have to fire up again for a week if they went on so." Had but a moderate fire at this time in the furnace. Says the extra pressure was owing to the engine being shut off so much. At the moment of the explosion witness was sitting on the rail of the fire-room gangway, at the outside of the guard, conversing with Bell, the other fireman. Witness heard a sudden cracking of the boiler, and attempted to look round to see what was the matter, which was the last he knew till he found himself in the water. Was severely scalded, but succeeded in swimming to the shore. Witness says that when there was no steam on the boiler, the top of his gauge-rod was so short as to fall three inches below the top of the muzzle of the steamgauge, and therefore did not indicate so much pressure as the gauge of the other boiler, that is, did not indicate the whole amount of pressure by three inches.

Edwin Bell, Fireman.-Was in charge of the

starboard boiler at the time of the accident. Left New-York with seven inches steam, and carried about the same pressure till through Hurlgate, after which carried 12 or 13 inches till dark.

Was then directed by Mr. Younger to keep 8 or 9 inches, which was done till 8 o'clock, when witness took his watch below. Came on duty, and took the fire again at Saybrook, at which time there were 8 or 9 inches of steam on, and the fire was run down. Capt. Waterman came and asked witness about the water, examined and found three full cocks. Witness had no occasion to supply his boiler by the hand-pump. At Lyme, the steam-gauge was at 12 or 13 inches, and on reaching Essex, the gauge-rod was within 3 or 4 inches of the upper deck.

When the boat stopped it soon rose to the deck. Witness then turned off the condensed water from the steam-gauge, which caused it to fall about two inches, but it soon rose as high as before. Tried the water-cocks, and found good solid water at three lower cocks, and steam and water at the upper cock. Went over to the larboard boiler when first we stopped at Essex, and found 3 cocks of good water, and the gauge-rod three or four inches from the deck. The gauge-rod of the starboard boiler usually stood higher than the one in the larboard fire-room.

Witness never saw the float rods of the steam-gauges so high as at this time. Has run in the boat from her first trip. Witness told Giles (Farnham,) when the latter came into his room, "that they would not have to fire up more than once more during the whole watch."

There was a light fire kept up between Lyme and Essex. Witness heard no steam blown off at Essex. The accident happened about 3 o'clock in the morning. The NewEngland came out from New-York before the Boston. At 8 o'clock the Boston was about two miles astern.

Isaac Seymour, Mate.-Agrees in the statements made by Mr. Vail. In the Sound, from Sands' Point to Matinecock Point, the steam stood at the pressure of about 8 inches, and Mr. Marshall was some time blowing off. Marshall said that it was made faster than he wanted it, and he should speak to the firemen. Thinks there were 10 or 12 inches on the gauge in the engine-room, at the time when the boat was anchored at Saybrook, and they commenced blowing off. Saw the water tried in the boilers at Saybrook, which showed plenty. The larboard boiler was then pumped into by hand.

Perceived no difficulty in working the boat, except at Saybrook. Was not apprehensive of any accident. Was employed in landing with the small boat at Essex. Saw Mr. Marshall visit the fire-room just before the landing at Essex. Witness was facing the dock when he first heard a cracking noise, and was in the act of turning towards the steamboat when the explosion instantly followed.