regulated at pleasure according to the nature of the wood or the number of cuts, though the saws always make the same number of strokes, viz. eighty in a minute. The drags which convey the timber to the saws, besides their progressive, have a retrograde, motion, and roll backwards when the timber is cut. There are likewise various ingenious contrivances for holding the timber while it is sawn, and also for following the natural bend of the wood when requisite.

Two of the saw frames are appropriated to deal slitting, an operation which is performed with amazing rapidity and the greatest precision. We have seen at one frame two deals ten feet in length, slit into four boards in the short space of ten minutes; and the two frames have produced in six days (working only seven hours and a quarter each day) thirty-four thousand superficial feet of timber.

The whole of this machinery, together with the three circular saws, are propelled by an engine of thirty-six horse power; wedges, and other light work for joiners, are cut by the circular saws. In an adjoining room are lathes for turning brass and iron work for capstans, windlasses, treenails, and all kinds of metal and wood required for the service.

Some very extensive waterworks are connected with this steam engine; iron pipes are laid at different parts of the yard, and on them, at certain distances, are fixed cocks, which, when required,

throw streams of water above the highest buildings. From these pipes all the offices and houses in the yard are supplied with water; and there are also pipes at the river side to supply the ships in ordinary with this necessary article of cleanliness.

Necessity is the mother of invention; the saying is well exemplified in the instance of the saw-mills. We have stated that the building stands on an eminence, which made it very laborious and expensive for logs of timber to be brought to the saw mills from other parts of the yard for conversion. This defect engrossed the mind of the ingenious constructor of the mills, and led him to invent one of the simplest and prettiest pieces of mechanism we ever saw, and which has completely remedied the imperfection.

The ground on the north side of the mill is appropriated to the stowage of timber. Rafts are floated from the river by means of a canal, which runs open about two hundred and fifty feet, and, on entering the rising ground, becomes a tunnel about three hundred and thirty feet in length, and opens into an elliptical basin which is in length ninety feet; breadth, seventy-two; and depth, forty-four.

The operation of raising the timber from this basin is worthy of observation, and the steady, though quick motion, with which it ascends, is truly astonishing. We have witnessed a balk, sixty feet long and sixteen inches square, raised

to the top of the standard, sixty feet, in the short space of twenty seconds! merely by the waste or condensed water being allowed to run into an iron vessel, to outweigh the timber. It is then farther lifted by two cranes, given motion to by a vibrating rod connected with the steam engine, and, when suspended on the said cranes (which are portable, and weigh about nine tons each without the load), the logs are transported to any of the stacks alongside of a railroad eight hundred and twenty-eight feet long, having an inclination of two feet ten inches in every hundred feet; so that its own gravity takes it down, and it is brought back by means of an iron chain winding round a large drum, which is moved by the engine. The speed with which it runs down with the loads is uncertain, but is moved back at the rate of three miles an hour.

There is a tank over each wing of the saw-mill building to receive the water when raised, fiftyseven feet long, thirty-two feet wide, and two feet deep; and they each hold about 22,500 gallons of

water.

Besides supplying the yard and the ships with water, this engine has to supply the same to the Royal Marine Barracks, Naval Hospital, and Infantry, or Chatham Barracks; these establishments at least consume from three to four hundred tons of water.

There is also a fifty horse power engine for pumping the docks, which works a pump of four

feet in diameter, which delivers about fifty-five cwt. of water per stroke; the strokes are from twelve to fourteen per minute.

In the same building is a twenty horse power engine, as a substitute, should anything happen to the above engine; it has two pumps, one of twenty-eight inches and the other of twenty-two inches, to drain the docks. This engine is also adapted to give motion to a three barrel engine pump for the fresh water, which will produce the same effect as the saw-mill engine.

The fans for blowing the smithy fires are driven also by this engine at the rate of one thousand revolutions per minute; and it drives a large volume of air, through proper passages under ground, to the smith's shops and the quantity is regulated by valves fitted into the tubes. This has been a very great improvement and all the dock yards now have been or are about to be supplied with the blasting machine, the smithy is rendered delightfully cool and pleasant by the constant current of fresh air, which makes it much more healthy for the people to work in.

The mould loft is a very capacious room with a fine even deal floor of three inches in thickness and coated over with black paint; this is the place where moulds for the various component parts of ships are made, and the true size, form and the dimensions of them are delineated for the guidance of the builder, which process is called "laying off;" it requires great nicety and sufficient practice

to lay off a ship on the mould-loft floor, as it is the very foundation from which the ship is built, and the excellency of a design may be entirely lost through neglect in this department.

No one can be called a good practical shipwright, unless he has a thorough knowledge in this branch of the practice of naval architecture, as the economy of material greatly depends on it. We should here observe that great care is taken in the Royal Dock Yard in laying off a ship, and well acquainted persons are intrusted with it. There are two persons at Chatham to delineate the lines and two to make moulds, apprentices are also sent to the loft to be instructed in "laying off," and the whole work is most admirably carried on.

The Frigate Mæander of 46 guns, which had been standing on the slip 16 years, was ordered by the Admiralty to be launched, and the 5th of May was the day our friend John Fincham, Esq. appointed for it. We were very glad in having thus had the opportunity of witnessing the English mode of fitting the launching apparatus. The principal dimensions of the Mæander are—