and one part of slaked lime. He then closes the retort, and mixes the two materials thoroughly by means of an agitator. The retort is next subjected to heat, (of a moderate degree at first, but heated till the bottom is nearly red hot,) which not only sets free the ammonia of the guano, but decomposes the uric acid contained in it, which yields also a considerable portion of ammonia. But as other gases besides ammonia are liberated by this process, in order that the ammonia may be separated from them, the whole of the gaseous products of the retort are passed through a condenser of a peculiar construction, filled with water. The ammonia is absorbed by the water, while the other gases being insoluble, make their escape through a pipe provided for the purpose, at the top of the condenser.

To form solutions of carbonate, sesquicarbonate, and bicarbonate (salts) of ammonia, the condenser is filled with a solution of ammonia, and carbonic acid passed through it.

To form solutions of the sulphate or muriate of ammonia, diluted sulphuric or muriatic acid is employed for the condensing liquid.

And for combining generally all soluble gases with liquids, the patentee states, that he finds a condensing apparatus of the particular form described by him, superior to all others. The advantage peculiar to it, appears to be that the gases are made to traverse over or through a very large body of water, by means of inclined shelves, while the head of water, the pressure of which has to be overcome, is extremely small.

ROBERT STIRLING NEWALL, of GATESHEAD, IN THE COUNTY OF DURHAM, for improvements in the manufacture of flat bands. Enrolment Office, May 16, 1842.

The improvements of the present patentee consist in manufacturing the flat bands used in mining operations, and for driving machinery, exclusively of iron or other metals. Three processes are described. According to the first, a flat band is manufactured, by subjecting a piece of iron or other metal of good quality, preferring that known as the best charcoal iron, manufactured in the usual way by rolling, to a process of drawing through rectangular orifices, or dies of hardened steel, in the same manner as in the ordinary and well-known operations of tube or wire drawing. The patentee considers it to be of importance that the piece of metal to be operated upon should be drawn through the die in a straight line at right angles to its edge; and as it is difficult to roll iron beyond a certain length, he suggests that it may be found convenient to

draw it in a hot state through dies. Again, as in the process of drawing the metal becomes hardened, the patentee directs that (if necessary) it should be annealed by heating it in a furnace, and after the oxide has been removed from it by means of diluted sulphuric acid, that the process of drawing should be repeated when cold. When a band of considerable length is required, it may be necessary to unite two or more bands together. Various methods of effecting this junction are pointed out and illustrated by drawings. Scarfing the ends and riveting are considered to be much preferable to welding or brazing, as the operation of hammering in welding gives a brittleness to the metal, which no subsequent process of annealing can remove, so as to give the hammered part the same strength which it had before; and in brazing, the union of the two metals is not such as can be depended on or should be trusted to. These bands, when of iron, may vary in thickness from

to of an inch, and in breadth according to the strength required. Flat bands manufactured in the way described, are stated to possess greater strength and durability than those of hemp or any similar material of the same weight; and if extreme lightness, with the greatest degree of strength, be required, steel may be used instead of iron. In some situations where the iron becomes rapidly corroded, the bands may be made of copper instead of iron or steel.

The patentee's second improvement con. sists in manufacturing flat bands of a combination of narrow bands or strips of iron, or other metal, which bands, for some purposes, particularly in deep mines, possess advantages over the flat bands before described, on account of the greater security against accident or sudden breaking which such a combination presents. The strips of metal are arranged side by side and fastened to cross pieces. Metal drawn through dies. as before described, is used; or metal rolled in strips, taking care to select such as are straight and free from flaws, and, if necessary, to cut their edges true and parallel, which may be done by circular shears. pieces of which the flat band is to be composed are laid side by side, and kept in a state of equal tension by weights acting over pulleys, while the cross pieces are riveted on and joined at the end by a butt or by an overlap joint. The cross pieces may be from 18 inches to 5 feet apart, the breadth and thickness of the component pieces of the band varying according to circumstances.

The

The third improvement consists in forming a flat band, by weaving narrow strips or wires of metal in a loom, the strips or wires which constitute the warp being wound on

separate bobbins and kept at a uniform tension during the operation of weaving. It is stated to be, in most cases, advisable to have the wire used as the weft of smaller size than that used as the warp.

METHOD OF LOWERING THE "LIGHTS IN SOME PARTICULAR ENGRAVINGS EXECUTED IN THE WOOD-CUT MANNER. SIR,-I here submit a new method of lowering the "lights" on the surface of some particular engravings executed in the woodcut manner, as, for instance, the copper blocks produced by electrography, and those formed by Mr. Woone's stereotype process : the lines of the pictures in both styles being all one height, on account of the design being engraved on a flat even surface. The metal casts or blocks are first "stopped" out in the darkest tint by the application of a hairpencil dipped in some strong varnish, as that of copal, asphaltum, or seed-lac, the first mentioned being the most preferable; and then attached to and immersed as positive plate in the single-cell voltaic apparatus used in electro-metallurgic experiments, letting it remain until the parts untouched with varnish have been corroded to the requisite depth. It should then be taken out, dried, and the varnish-brush applied to those portions which may be considered deep enough, repeating alternately the varnishing and corrosion, until the cut is graduated to your desire. The character of the engraved lines will not be much injured by the electroetching process, as the corrosion proceeds with evenness and regularity. The more simple application of nitric or other suitable acid, might probably be found efficacious when the design is of a bold or rude character, and strongly lined.

As a mode of lowering blocks of the above description for typographic printing has long been sought for, the insertion of this little hint may be of service to some of the readers of the Mechanics' Magazine. I have the honour to be, your obedient servant,

M. T. BRAZENndale.

THE MAMMOTH STEAM SHIP.

SIR,-I have, in common, I dare say, with many of your readers and subscribers, been for a long time expecting to see some account of the progress made in the building of the above vessel, particularly as it is understood there are three great principles in the course of being tested in her construction. Will you be kind enough to allow me to ask the

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favour of some one of our Western friends to furnish us with such particulars as may be known to them, of its present state of forwardness? The three principles I allude to are, 1. The fitness or suitability of sheet iron for such enormously large structures. 2. Has the practice of transatlantic steam ship-building, been carried far enough to justify the experiment of magnitude attempted in this case, and is it necessary in a mercantile point of view? (The recent voyage of the Great Western to Liverpool with 28 passengers, appears to prove otherwise.) 3. What are the advantages expected to result from the use of the "Trunk Engine?" Does it consist in cheapness of first cost, simplicity of parts, compactness and taking less room, or less consumption of fuel?

Some information on these general heads, as soon as they can be collected, will much oblige many of your readers, as also, Sir, your obedient servant,

AN OLD STEAM BOAT ENGINEER.
Tottenham,
May 17, 1842.

NOTES AND NOTICES.

The "Locomotive" Steamers.-A new steamer has made its appearance in the river, with the name of the "Locomotive No. 1," and is to be speedily followed, it is said, by several others of the same description. It is a small boat, of the class that ply between the bridges, and is called the "Locomotive," from the circumstance of its being fitted with boilers of the same sort as are used in railway locomotives namely, high-pressure tubular boilers. There is much fairness in this choice of a name, since it indicates at once to all concerned the degree of danger to which they are about to be exposed in embarking in the vessel. People accustomed to travel by the River boats, which are generally worked at 4 and 5 lbs. pressure, might but for this warning, have justly complained that they had been entrapped into a travelling proximity with a pressure of from 70 to 80lbs. Whether there is any actual danger or not attending the use of such high-pressure boilers, may be matter of question; but there can be none about the perfect propriety of letting every one know what he has to look to. correspondent (Vulcan) suggests, that it would perhaps be still fairer if the boat were called "The High Pressure No. 1."

A

A Floating Manufactory.-Amongst the strange craft to be seen navigating the Ohio, is a floating "Glass works." "A large boat," says Mr. Le Cras, "is fitted up with a furnace, tempering oven, and the usual apparatus proper for such an establishment. It is on full blast every night, melting glass ware, which is retailed all along shore, as the 'Works' float down the stream."

Quick Packing.-A workman at the Sandwich (Mass.) Glass Factory has been known to roll in separate papers in one day five thousand three hundred and sixteen tumblers. Some one noticing the number by a watch, saw him pack twelve dozen în six minutes!-Le Cras.

Weaving and Patriotism Extraordinary.— The Limerick Chronicle has a strange story about a Garryowen weaver, of the name of Lyons, who can produce a man's apparel complete from the loom without stitch or seam." "We have seen," says our contemporary, "coats and trowsers, with but

The

tons and all other necessary appendages, wrought by this poor but most ingenious artist." strangeness, however, consists less in the man's performances, though certainly they are remarkable enough, than in the use which he is about to make of his discoveries in weaving. "Rather than injure," so the story proceeds, "such of his fellowcountrymen as carry on the business of woollendrapers, and follow the trade of merchant tailors, by selling his secret and teaching his art to an English capitalist that has offered for both, and who, by the application of steam power and appropriate machinery, could manufacture all sorts of men's clothing, and thereby, at no remote period, leave multitudes of tailors disemployed," he has determined to emigrate with his invention to "some distant land!" There is a patriot for you! A perfect "gem!" But he has, it appears, his consolation. He crosses the Atlantic to find "a home and happiness" under the star-spangled banner, and when he "shall have settled at New York, whither he intends to emigrate," his mother country is to be paid off in grand style for its indifference to such extraordinary merit. "Jonathan will heap reproaches on us for neglecting to encourage and succour the most extraordinary self-taught weaver that ever left our shores." Jonathan ought rather -if there be any truth in the story-to shower thanks and blessings upon us for making him such a present. But since "an English capitalist" has already offered to buy both the patriotic weaver's secret and to pay him for teaching his art, what ground is there for complaining that he is in want either of encouragement or succour? Why not close with the English capitalist at once? Why not eschew blarney and stay and make himself rich and happy where he is?

American Locomotives.-A remarkable performance on the Philadelphia and Reading Railroad.A new geared truck locomotive-engine, built by Messrs. Bald win and Vail, with six wheels and outside connexions, and weighing, in running order, 30,000 lbs., hauled lately a train of 117 loaded cars, weighing in all 590 tons, from Reading to the inclined plane, on the Columbia Railroad, fifty-four miles, in five hours and twenty-two minutes, being at the rate of over ten miles per hour the whole way. She consumed 2 6-10ths chords of wood, and evaporated 3110 gallons of water. Whole length of train, 1402 feet, or eighty-two feet over a quarter of a mile. Whole length of level, over which the train was hauled, twenty-eight miles; longest continuous level, 8 1-10th miles; total fall, from the point where the train was started to where it stopped, 210 feet.

Rates of Speed on Railways.-The following are the average rates of speed observed on seven of the principal English railways; London and Birmingham, 27 miles per hour; North Midland and Midland Counties, 29; Newcastle and Shields, and London and Brighton, 30; Great Western, 33; Northern and Eastern, 36.

Mills Started and Mills Stopped.-It appears, from the Report of the Factory Commissioner, Mr. Horner, that in his district, which includes Lancashire, the North Riding and part of the West Riding of York, Northumberland, Cumberland, and Westmoreland, there have been, during the three last years, 91 new mills started, employing engines of 3,350 horses power and 16,750 hands; and 138 stopped, which employed engines of 6,788 horses power and 29,363 hands.

Machinery the Friend of Wages.-We believe it may be safely asserted, that wherever machinery has been introduced, there the aggregate amount of wages paid has been increased, and that wherever it has diminished, there the aggregate amount of wages paid has fallen likewise. Machinery has never increased but as a means to the increase of

wealth. When wealth is increasing it must be employed in further production, or it would not continue to increase. But farther production requires greater employment of labour, and at the same time increases the fund for its remuneration. From this increased fund the labourer derives an increased share, for the object of the employer is to augment the amount as well as the rate of his profit. And this he effects not by diminishing his hands and limiting his new machine power, but by extending its application to the widest range commensurate with the funds he can employ to make and to work it, so as to maximise its capacity and compass the largest scope both of product and profit. -Facts and Figures.

Death of Mr. Samuel Seaward.-We lament to have to record the death, on the 11th inst., of this eminent practical engineer. Few establishments in this country have contributed more to the progress of steam navigation, than the firm of Messrs. Seaward and Capel, of which the deceased was an active partner. Mr. S. Seaward was a Fellow of the Royal Society, and a Member of the Institution of Civil Engineers, in the proceedings and welfare of which he latterly took a most lively interest.

Four and Six Wheel Engines.-From the Returns made to the Board of Trade by the different Railway Companies, it appears that the number of six wheel engines now in use is 605, and of four wheel 224. We hope, ere long, to see the latter number reduced to 0.

The Transatlantic Steamers.-The Great Western, which sailed from Kingroad, Bristol, on the 2d ult., for New York, reached that city on the 17th, after a passage of 14 days and 12 hours. She sailed from New York for Liverpool on the 28th ult., and arrived off the floating-light early on the morning of Wednesday, the 11th inst., having made the run in 12 days and 8 hours, the shortest passage ever made between New York and Liverpool, as well as the shortest ever made by the Great Western. She has certainly made the passage to Bristol in a space of time very little greater-12 days and 12 hours-but the difference of the distance between New York and Liverpool, as compared with the distance between New York and Bristol, is equal to at least six hours' steaming.Liverpool Times.

East India Company's Steam-Frigate Acbar.-On Sunday last this splendid war-steamer left her anchorage at Gravesend, bearing the pendant of Commodore Pepper, of the Indian navy. The Acbar is a steam-frigate of the first class, armed with two eight-inch guns, and four long 32-pounders, with a complement of 160 men; carrying five boats, on two of which are mounted brass 12 lb. howitzers. The engines are of the collective power of 350 horses, manufactured by Napier of Glasgow. She carries 500 tons of coal, which, with a consumption of a ton an hour, will enable her to steam 20 successive days. The Acbar made her passage from Gravesend to Falmouth, a distance of 370 miles, in 36 hours, which gives an average speed of more than 10 miles an hour.-Times.

INTENDING PATENTEES may be supplied gratis with Instructions, by application (postpaid) to Messrs. J. C. Robertson and Co., 166, Fleet-street, by whom is kept the only COMPLETE REGISTRY OF PATENTS EXTANT (from 1617 to the present time). Patents, both British and Foreign, solicited. Specifications prepared or revised, and all other Patent business transacted.