SCIENTIFIC AND MISCELLANEOUS INTELLIGENCE.

Evaporation.-Bishop Watson, by an experiment on a closemown grass-plat, and after a long period of dry weather, found that the quantity of vapour given off invisibly in 12 hours of a summer's day, amounted to no less than 2,720,000 gallons on a single acre, or about 1,600 gallons of water. Such is the gigantic scale on which nature silently and unostentatiously performs her operations.

Animal Temperature. It is a curious fact that men of all nations and tribes, and of all climes; whether they feed on herbs, desh, milk, or pulse, have very nearly the same bodily heat, that is, 37° 1 Centigrade or 99° Farenheit. This heat, however, is a trifle augmented when a man is transported to a cold, and on the contrary diminished when transported to a hot climate. Birds have the greatest bodily heat, mammiferous animals next, then man, amphibious animals, and some insects.

Continuous Bearing Rails.-J. Binns, Esq., Secretary of the City and Richmond Railway, is about to lay down a mile of his new patent continuous bearing rails, on the Greenwich line. We have a high opinion of this invention, and shall be happy to see its operation.-ED.

Perkins's New Locomotive Engines.—Mr. Perkins is constructing some locomotive engines with his new-we think we may call them everlasting-boilers, to bring to a decisive test on the Southampton railway. If the invention succeeds, we shall have no trouble hereafter about incrustations, nor the consequential dangers of bursting.-ED.

North-West Passage. It is said Government contemplate sending out, next summer, another expedition to attempt the northwest passage. If Government intends it as a matter of curiosity, well and good; they may as well spend some money that way as any other. If they have utility in view, they had better try to find the philosopher's stone. Suppose a north-west passage was found, where is the cui bono? It might look well on our maps and globes, and make a pretty tale for another Scott; but would it be traversed once in a century?

High Velocities with Canal Boats.-In the Mining Journal of October 18, are detailed some interesting experiments on the Ardrossan or Paisley Canal. In the Forth and Clyde, experiments were several months back made, by fastening together two single gigboats, making what is called a twin-boat, and it was found that the quicker the boat went through the water the less was the wave or surge. The consequence was, the building of a twin-boat of a

gig shape, 60 feet long and 9 feet wide. After this, the Ardrossan Company launched on their canal a single gig-shaped boat of the same length and 4 feet wide, with which, carrying 24 persons, and towed by two post-horses, 7 miles were traversed in 45 minutes, and the faster they went "the more entirely the surge disappeared." It is supposed, from these experiments, that the banks of the canals will be less injured in very high than they have been in very low velocities, and that, ere long, canal boats will compete with stage coaches in velocity. [Why not at once tow the boats with a loco, on rails laid on the banks, and thus rattle along 20 or 25 miles per hour?-ED.]

Mr. Gompertz's Improved Method of applying Oars and Sculls to Rowing Boats.-(Communicated by the Author.)-The numerous serious accidents which occur to row-boats, by collision with steamers, &c., has induced Mr. Lewis Gompertz to suggest some modifications in the manner of applying oars and sculls, so as to render them more safe.

The first plan is, by causing the boat to go forwards (instead of backwards) while the rowers, as usual, pull backwards; to effect which, the situation of the rowlocks (the places which hold the oars) is different from the present one, viz., the one for the right oar is to be on or near the left side of the boat, and vice versa, and they are to be higher than usual, so as to prevent the oars from rubbing against the opposite sides of the boat. The oars, then, are not to be held at the ends, but towards the middle; or, in other words, the hands of the rowers are to be between the blade of the oars and the rowlocks, and the concave part of the blade pointing backwards. The boat will then, contrary to the usual way, go forwards, while the oars push the water backwards; the eyes of the rowers thereby being directed to the objects they are approaching, without the difficulty of continually turning their heads to look behind them. By this plan, the oars will be shorter between the blades and the rowlocks, and still more so in the part which projects, thus being more out of the way of objects. It will, however, be necessary for the oars to project a little on the opposite sides of the rowlocks, and perhaps to be loaded with a little lead, in order to balance them, and prevent unnecessary labour in raising them out of the water.

When sculls are used, the rowlocks may be nearer to the centre of the breadth of the boat, an obstacle may, however, then be caused by the balancing portions of the sculls interfering with each other's motion. But by making one of the rowlocks a little higher than the other, or by some other simple contrivance, it is hoped that this may be obviated.

The power necessary to apply to these oars or sculls, to produce the same effect as with common ones, will be the same as with them, provided the distance of the hands from the rowlocks, and the rowlocks from the blades of the oars, &c., be the same, as it

matters not on which side of the object to be moved the power is applied, the arc described by the hands being the same in both cases, and also that of the blades if free. If these methods, however, should be less agreeable to the rowers or the other passengers, still, in boats for dangerous places they may not be objected to.

The second alteration relates to the rowlocks themselves, and is to give freedom to the oars or sculls when, by unskilful rowing or accident, they come in contact with any object so as to injure the boat, and also to prevent loss of motion and noise.

The rowlocks are for these purposes made separate from the boat (and in form thus ) into which the oars or sculls must fit tightly, with no more room than necessary for the feathering of them, and they must be attached to the boat by an axle going downwards, and working in it, so that the rowlocks shall turn with the motion of the oars, &c., but being provided with a stop, so that they shall not go too far to allow the oars, and to be easily replaced when taken out.

Mr. G. has not tried these plans, but hopes experience will prove their efficacy.

Figure of Vessels.-Mr. Lewis Gompertz has also, with deference, submitted to scientific and practical men, the following alteration in the shape of ships and boats, with a view to increase their speed:

The best shape for ships and boats, to give them speed, would appear to have been long ago discovered by theory as well as practice; yet the shapes adopted do not seem the best for this purpose. The front and the hind parts of vessels ought not, it appears, to be alike, nor nearly so (as they now are), for the very simple reason that their offices are quite contrary to each other: the prow ought to impress the water as little as possible, while the stern should offer as much resistance to it as possible; therefore the prow cannot be of too acute an angle, nor the stern too obtuse a one. The latter, indeed, should not, it appears, be angular at all, neither perpendicularly nor horizontally; but should offer a broad flat surface, or rather a concave one for the water to press against, and thus powerfully push the vessel on.

In order to see the action of the water, fill a long pan with birdseed, instead of water (the effect of which is very similar, though not precisely so), and place a piece of wood in it of the shape of the vessels here recommended, but the action will be best seen if the front part be only made taper sideways, and is not bevelled from the bottom. Then gently move this piece of wood forward, and it will be seen that the front part pushes the seed forward by the angular part more and more as far as the base of the angle; during which the seed rises into a hill before it on each side, until the square part of this vessel reaches these hills, when the swell of seed begins to descend, and retrograde till it reaches the stern,

and then it makes a sudden and forcible turn again, striking the stern with great power. There two streams are clearly seen, and the seed (or back-water) behind it can also be clearly seen closely following them up and adding greatly to this effect. This is the action of the surface, below which it must be somewhat different; but the lower seed or water must, it appears, also participate in the action, because it helps to fill up the vacancy which the vessel is continually leaving behind it.

The reason for preferring a concave to a flat stern is, because a concave one better prevents the two streams from escaping sideways, or from coming into collision with each other, and destroying each other's motion, before they fall in the vacancy left by the vessel.

If, then, water and bird-seed act similarly, the effect it is presumed will be as is here anticipated; but the superior fluidity of water requires the experiment to be on a larger scale, and water will then show more of the minutia than bird-seed, and it will then also be seen that circles and other curves are formed in the water by the meeting of the different currents, which cannot be shown by bird-seed, but only a small part of the water will be thus affected.

Locomotive Steam Engine.-Messrs. R. and W. Hawthorn, the eminent engineers of this town, have just completed, for the Newcastle and Carlisle Railway Company, a new locomotive steam engine. The engine is estimated at a power of about 40 horses. The machinery was put into operation at the extensive works of Messrs. Hawthorn, on Wednesday, the 12th, a large party of ladies and gentlemen having been invited to witness its first performance. The company, amounting to 80 or 90, included many engineers, architects, and others familiar with mechanical subjects. These scientific gentlemen had been attracted to the spot, from a desire to examine a new and vastly improved arrangement, invented by Messrs. Hawthorn, of the hand-gearing for working that portion of the mechanism called the slide valves. The ease and rapidity with which the motion of the engine was reversed by the man in charge of it, elicited the opinions of competent judges that the arrangement is as simple and perfect as the nature of the motion will admit. On Thursday the engine was conveyed to Blaydon, and made her first trip to Hexham in a highly satisfactory manner. It was ascertained that, in one part of the journey, she ran over a mile of ground in one minute-being at the rate of 60 miles an hour. It should be observed that her burden in this experimental trip consisted of only one carriage of passengers; but she had to contend with the opposing force of a strong west wind. At this tremendous speed it was with difficulty that the persons in charge of the engine could keep their places on the tender.-Newcastle Journal.

Heat received from the Sun.-The actual amount of solar heat

derived from the sun annually by the earth, has been estimated to be sufficient to melt a coat of ice encompassing the whole globe, and 14 metres or 15.3 yards thick.-Whewell's Report on Heat, &c. p. 31.

If thus, as Dr. Black observes, 140° of heat be lost in the liquefaction of ice, the whole annual solar heat received would raise a coat of water, surrounding the whole globe, of 11.9 yards thick, from the temperature of freezing to that of boiling. Or, accounting it 12 yards, and the pressure lb. per square inch for every foot, the above crust of water is equal to about 44,000,000,000,000 tons nearly.-ED.

Railway Coaches.-There is now just completed at Mr. Jeffery's coach manufactory, Gray's-inn-road, some railroad coaches, intended for a railway at the Island of Cuba, of a very superior description. The sides are so constructed that they may be used entirely open from end, or used with large plate glasses, and for bad weather, Venetian spring blinds, all working in grooves. Each will carry 18 persons. In order to keep the roof from the heat of the sun, an additional canopy is placed at some distance above. The under carriage parts are constructed with a peculiar combination of springs, which prevent the shock of the carriages striking each other, being in the slightest degree felt by the persons inside. The communicating bars pass through a succession of brass bearings, accurately turned, and prevent any noise; and the carriages are painted a very rich amber, relieved with crimson lines. From the peculiarity of their construction, they are the strongest and most commodious vehicles ever built for the conveyance of passengers.

Level of the Land and Sea.-Mr. Whewell, at the late meeting of the British Scientific Association, urged the propriety of making observations to fix the relative level of the land and sea, for prosecuting which a sum of 500l. was then voted. The object of Mr. Whewell is to ascertain whether the land at various places is permanent, or rising, or falling. No doubt can be entertained of the great interest of such an object. Mr. W., however, raised the question how this was to be ascertained-from the mean level of low or mean tides. Our opinion is, it should be from the mean height of the water-in the same way as we reckon from the mean height of the barometer-supposed to be taken every moment during a complete period of all the courses disturbing it, which is about 18 years.

Old Thermometer.-Mr. Babbage exhibited a thermometer at the same meeting lately discovered in Italy, and supposed to have been manufactured for the Societte del Cimento. It appeared to be filled with alcohol, with a spherical bulb, and its stem divided into fifty equal parts by brads, attached to it by fusion. There were no fixed points, so that nothing can be known of its actual indications.