made with every possible power, applied to ascertain their stability; and as every one who has witnessed the experiments is fully convinced of the superiority of the blocks, I trust I shall not be considered too presuming in recommending their adoption for claws as well as anchors, as I am given to understand the cost will not much exceed the expense of making and fixing a claw, which is liable to injury, by vessels grounding on, or hooking fast to it, nor is its durability beyond 40 or 50 years, even where it remains undisturbed, whereas the cast-iron blocks will last for many centuries.

I am likewise informed that the Blocks may be cast at the foundry, in the yard, if your Honourable Board should approve of a furnace being erected for that purpose, which would materially lessen the expense.

I have hereunto annexed a description of the trials, and have forwarded by this night's coach, two drawings. No. 1, showing the present method of securing the ground-chain.

2, showing the manner in which the mooring-block

was tried.

And by Clark's waggon, a model of the block.
I am, Sir, &c. &c. &c.

J. PARK.

Description of the Trials made with the Cast-Iron MooringBlock, invented by me, and now humbly submitted for the consideration of the Honourable Navy Board.

First. The cast-iron mooring-block, weighing 142 cwt. was placed on the shore some distance from low-water mark, and an anchor of 35 cwt. (exclusive of the stock, which weighed about 35 cwt.) was also placed the same distance from low-water mark, and 65 fathoms from each

other,

other, on ground of the same quality; 15 fathoms of mooring-chain were attached to each, and to the end of each chain four treble-blocks of 22 inches; four threefold purchases of new 6-inch bawser rove, and two mooring-lighters, with 40 men in each, grounded, one abreast of the cast-iron block, and the other abreast of the anchor; the falls were brought to the capstans and windlasses, and the strain applied to heave the mooring-block and anchor towards each other.

Both drew; the former one inch to one foot of the lat ter, until the mooring-block had drawn about the distance of its own base, when having completely buried itself, it became stationary, but the anchor continued to come home (notwithstanding it was buried to the upper flook) until every one present was satisfied that any farther trial with an anchor of that weight was useless.

Second, being willing to make further trial, I caused an anchor of 95 cwt. (namely, the Nelson's best-bower) to be laid down as before, and the same purchase to be applied; but the power not being sufficient to move either the block or anchor, 10 additional men were sent into each lighter, when the anchor started, and continued drawing, notwithstanding it soon buried itself as the former had done, but the block remained immoveable.

.. Although this trial was very satisfactory, yet wishing to ascertain the power of resistance which the block possessed, I caused the following one to be made.

Third, an anchor of 41 cwt. was laid down about 60 feet behind the large anchor, and attached to it by cable, and on applying the same purchase as above, the large anchor drew until the cable between the anchors became taught, when it was found necessary to increase the power, which, being done, both anchors started, and continued to come home, until the superiority of the mooring-block Y 2 (which

(which still remained firm) was declared to be so manifest, that no further experiment was necessary, it being the opinion of the gentlemen under whose inspection this last uial was made, viz. Admiral Sir Richard Bickerton, baFonet; Rear Admiral Foote; Commissioner the Hon. Sir George Grey, baronet; Captain Sir James Athol Wood Hewit, and the principal officers of the Dock-yard ;— that it was much superior to any thing yet offered for the purpose of securing the ground chain of the moorings, and that its introduction would prove advantageous to the service, particularly in shoal-water where ships had to pass over the anchors.

J. PARK.

Statement of Trials made with a lighter Cast-Iron MooringBlock.

First, the mooring-block weighing 115 cwt. was placed on the shore near low-water mark, and also an anchor of 95 cwt. (exclusive of the stock) about 65 fathoms from each other, with 15 fathoms of mooring-chain attached to each, and to the end of each chain 4 treble-blocks of 22 inches, 4 three-fold purchases of new 6-inch hawser rove, and 9 mooring-lighters, with 50 men in each grounded, one abreast of the mooring-block, and the other abreast of the anchor; the falls were brought to the capstans and windlasses, and the strain applied to heave the mooringblock and anchor towards each other (similar to the trials made with the former block, a statement of which accompanied my letter of the 2nd of November last).

The block and the anchor both drew about the distance of seven feet, when the block became fixed, but the anchor continued to draw as long as the purchase was applied.

Second, an anchor of 43 cwt. was laid down about 10 fathoms behind the large anchor, and attached to it by

cables

cables (termed by seamen, "backing an anchor'), when the purchase was again applied by 64 men in each lighter: the large anchor drew, taking the small one with it, until the latter had buried itself up to the crown, when the anchors became stationary, and the block began to draw, and continued to do so while the strain was applied.

Third, having removed the anchor of 43 cwt. and laid down one of 23 cwt. instead, at the distance of 15 fathoms behind the large anchor, the same purchase was again applied, when both anchors came home.

The block, after having drawn about 7 or 8 inches, became fixed, but the anchors had drawn 13 feet, and kept coming home as long as the purchase was continued, and until it was evident that the block was superior to the anchors.

The foregoing trials were made under the inspection of Admiral Sir Edward Thornbrough, K. C. B.; Rear Admiral Halkett; Commissioner the Hon. Sir George Grey, bart.; Captain Hewitt; the Master Shipwright, Master Attendant, Engineer, and Mechanist, &c. &c. &c.

J. PARK.

REFERENCE TO THE ENGRAVING.

AAAA, Fig. 1, (Plate VII.) the extent of the lower flat of the block.

BBBB, the extent of the upper-flat.

CC, for lowering the block into its place.

D, the neck of the block, to which the chain is attached.

E, the shackle which connects the mooring-chain to the block.

Side Views.

FG, gives the block an inclination to dive into the ground, when strain is applied.

Improved

Improved Method of heating Copper Plates.

By Mr. JAMES RAMSHAW, Copper Plate Printer,
Fetter-lane, Fleet-street.

With an Engraving.

The Gold Isis Medal was voted to Mr. JAMES RAMSHAW for this Communication.

From the TRANSACTIONS of the SOCIETY for the Encouragement of ARTS, MANUFACTURES, and COMMERCE.

I BEG leave to present, for the approbation of the Society, a representation of my apparatus for an improved plan of copper plate printing, by the use of steam in the place of charcoal fires, the effluvia of which are so injurious to the health of the workmen, and at the same time subject to many accidents by fire, as by the old process, each man works over a charcoal fire, without any chimney to carry off the vapour arising from the burning charcoal. Thirteen of those fires I formerly had in my work-shops, and one sea-coal fire or stove in my drying-room, fourteen fires in the whole by my new process, the use of the thirteen charcoal fires is superseded. A full representation of the apparatus, with the mode of application, will be given by referring to the accompanying drawing, which is a section of my premises, employed in the copper plate printing business.

A, (Plate VIII.) is the fire-place. B, a small boiler, containing only thirty gallons of water, with two safetyvalves. CCC, are the pipes for conveying the steam to the plate-boxes, DDD: these boxes are of cast-. iron, thirteen in number, and supply the place of thirteen charcoal fires. They have a flat surface, sixteen inches square, half an inch deep at the sides, running to

three