The vacuum in condenser was 27 inches, the barometer being 292 inches.

The weight of circulating water was about 430 tons per hour, and the speed at entrance and exit from 0.28 to 0.30 that of the vessel.

At very low speed (28 revolutions) the temperature of circulating water at exit was reduced to 73°, and that of feed to 89°.

This winter the vacuum has risen from inch to 1 inch.

These results seem to show that, provided good care be taken to reduce as much as possible the resistance experienced by the circulating water, the circulating pump may be dispensed with without increasing the ordinary condensing surface. I confidently expect that even at low speed with strong head wind the vacuum would be sufficient.

DISCUSSION.

Mr. J. SCOTT RUSSELL, F.R.S.: My Lord, I have carefully followed the description and drawings of this very elegant construction. The inventor has got over a great many difficulties here in an extremely simple manner, and I especially call your attention to the excellent arrangements by which the whole work of the condenser is done I might almost say at no cost at all, because the whole of the circulation of the water current is effected by the simple movement of the ship. I do not know whether you have observed this curious S-shaped canal, which runs right across the ship; the S shape at one end is turned to the bow of the ship, the other end of the S is turned towards the centre of the ship. It thus forms a continuous channel opening to the sea right through the ship by means of the condenser, and being of large area there, a very slight motion ahead with the entrance properly shaped sends a current of water right through the condenser. To show how modest a current, well applied and judiciously used as it is here, will accomplish that, he tells me that a small jet of steam when she is lying at anchor sending out the water at the after one of these mouths is quite enough to cause the current to maintain the vacuum at a height of 26 inches, which you know is a high condition for the vacuum of a steam engine. I say that the great reputation of our old correspondent Mr. Normand, who has so long held a high position at Havre, and who has already communicated to us so many valuable Papers, is thoroughly and entirely maintained by that so kindly read to us by his son.

Mr. NORMAND: I should like to say one word. It is not a new thing to utilise the velocity of a ship for the purpose of causing circulation of the water in the condenser; only when you use it you are obliged to have an immense quantity of surface condensation, because the condenser is not arranged so as to cause the resistance to be as small as possible. I should say that in ordinary condensers nothing is done to prevent the resistance of the water from being considerable. In these engines I have a very small surface in proportion to the steam used, and I have done it by having an immense quantity of water instead of surface. In that small engine I have more than 430 tons; that is to say about three or four times the general quantity of water that is passing through ordinary condensers. I am much obliged to Mr. Scott Russell for the remarks which he has made.

SS

ON YACHT MEASUREMENT.*

By E. C. STERLING, Esq.

[Read at the Seventeenth Session of the Institution of Naval Architects, 8th April, 1876; the Right Hon. LORD HAMPTON, G.C.B., D.C.L., President, in the Chair.]

Most naval architects, having other occupations than yacht building, it is probably safe to assume that but few have turned their attention to that branch of the art. Those that have done so can hardly have failed to be struck at once by the vast importance of the Rule of Measurement under which a yacht has to sail, and with reference to which she must therefore be constructed. Few yachts but at some time in their career are raced, whilst a large proportion are built especially to that end: hence racing tonnage is the acknowledged criterion of size in yachts. In the case of cruisers which have never been raced builders' tonnage is quoted, and is sufficient to give a good notion of a vessel's size, for its results seldom differ much from what until the last few years was the only racing measurement, viz.: that of the Royal Thames Yacht Club, which first introduced the improvement of measuring length on deck instead of along the keel, thereby doing away with the premium on raking the stern-post-a practice which has naturally grown up, producing vessels absurd in form under water, and with a strong tendency to run off the wind; moreover, they were of course vastly larger than their nominal tonnage. There can be no doubt that the alteration in the Rule instead of being, as was by some predicted at the time, disastrous, has been on the contrary most beneficial. vessels built under the old Rule and altered under the new one are stated to be much improved by the change; and we know by experiment that the best vessels of the old days have not a chance against the modern specimens.

Displacement.

Some

New measurement, as understood in the Mercantile Marine, is of course nearly related to displacement, of which hitherto no Yacht Club has taken cognizance. Many persons have thought that to adopt displacement as the standard would be a desirable

Received 1st April, 1876.