height of about 30°, served admirably to protect us from the winds towards the S. W. and North, and, if they did interfere with the ruder eye observations of some phenomenon near the horizon, they contributed to the advantage of telescopic observation with high magnifying powers directed to the zenith. Here, therefore, was the place where the great Pattinson equatorial must be erected, if at all.

Schemes for carrying this up the mountain had been devising all the time by our friends below, who were much interested in the realization of this marked feature of the expedition, and Mr. Goodall had at one time nearly organized relays of men for the transport to Guajara, but when they heard of the Alta Vista they one and all declined to have anything to do with the matter. But it must be accomplished; so on the 25th of August, leaving the men to roof in the newly-built walls, 1 descended the mountain to see what could be done in the now re-affirmed impossibility of carrying up the great telescope.

This instrument, with an object glass of 7 inches aperture and 12 feet focus, and with an equatorial mounting entirely in metal, and of the first class of finish and perfection, in accordance with the requirements of modern astronomy, had been taken to pieces by its maker in England, as far, I presume, as he had thought safe or practicable for its re-ercction on a mountain side, far from the resources of workshops. But as he had not reduced it to its primitive elementary parts, the unwieldier masses could still be subdivided and packed up into smaller parcels. To this, therefore, I applied myself, and assisted by an ingenious mechanic of the place, we separated, and finally packed in thirteen boxes what had been arranged by the maker in three. Then starting from the town at daylight on the 30th of August, with eleven horses and men, the whole of the cases were brought up to the Alta Vista by sunset the same evening.

The next day, Sunday, there was a storm of wind and sand; and, though it had not subsided, on the Monday we began the erection of the wooden pier, filling it with lava blocks, after it had been duly orienté on its foundational beams fixed into the ground with lime. Then came the unpacking of the boxes, and the recomposition of the instrument, and on the second day the complete equatorial, with clock motion, axes well adjusted, and verniers reading off accurate places on finely divided circles, was in full operation, the first time that such a thing had ever taken place so high above the level of the sea. But now only a fortnight of our prescribed time remained, and there were marked indications of a premature breaking up of the fine season. I set to work, therefore, without loss of time, to determine, in the first place, the degree of definition in the atmosphere; for very grave doubts had been thrown out that the hot vapours from the Peak would be utterly fatal to telescopic vision. The definition, however, proved admirable; so much so, that not only once, but every night for a week, I could see that difficult test B and C of y Andromeda as two distinct stars; nor could I find any object in the lists of the "Cycle" that were not separated by the telescope and with ease.

Equally with regard to the range of visibility, did the atmosphere approve itself; for the very faintest star to the practised eye and powerful telescope of the observer of the "Cycle" proved easy to even an inexperienced person in the Pattinson equatorial.

Directing them to planetary bodies, the fine division of Saturn's ring-a much contested matter-came out unmistakeably, and revelations of clouds appeared on Jupiter's surface which were eminently similar in form, and as continually interesting in their changes as those of the sea of lower clouds brought about Tenerife daily under our eyes by the N.E. trade wind. Of the moon some extraordinary views were obtained, notwithstanding its unfortu

nately low altitude at that time; and the sun was observed both optically and photographically.

Daily, however, the weather, which had been in a manner disjointed by the storm on the 1st, was becoming worse; and the wind, continually increasing, now began to shake the telescope so as to prevent the employment of high magnifying powers. Then the sky became cloudy, and, at last, on the 14th of September, the storm broke in earnest, beginning with a rattling fall of

hail.

That night above two inches of rain fell, and the climate altered so much that the natives would no longer remain with us. But the temperature was by no means unbearable to Northern men, and the sailors from Mr. Stephenson's yacht, proving good men and true (William Neal, the carpenter, most ingenious and able with his tools in every variety of work, and William Corke, the Second Mate, with much capacity for observation), I still hoped to be able to see out the last of the clouds and to finish several series of observations which had been interfered with by them. The break up of the summer weather had, however, been too complete, and though we stayed till the last possible day we never saw the clear sky again; so, on the 19th, we dismantled the buildings, made a caché (sic, in orig.) of such materials as might be useful in a future year, and went down to Orotava with the instruments and baggage.

During the Alta Vista period of our labours the smaller instruments before employed at Guajara were again in action; an improved method of observing the black lines in the spectrum was devised; some meteorological ascents and descents of the mountain were made, according to the suggestions of the Royal Society; and Humboldt's horizontal fluctuation of the stars, and the nature of the ice cavern, as recommended by Sir J. Herschel, were examined into. The crater of the Peak, the Montana Blanca, and various places remarkable for their geology or botany, were visited with hypsometric instruments, and with a photographic camera, by the aid of which about 200 pictures were obtained.

Finally, in concert with a Spanish gentleman of great local knowledge (Don Martin Rodriguez of Cegas) I examined the upper part of the mountain, and found a station that with a little expense might be made available for another year, and, besides greater height, would possess some other advantages over either the Alta Vista or Guajara.

Arrived in Orotava I employed myself for a week in settling the accounts, in examining the zeros of our meteorological instruments, and in photographing and measuring some remarkable volcanic teatures in the neighbourhood, and also the great dragon tree, as recommended by Sir John Herschel.

Then on the 26th of September I rode over to Santa Cruz, and having examined the tide guage which, with the assistance of Mr. Hamilton and the warm co-operation of the Spanish engineers, I had had constructed on the mole to meet the wishes of the Master of Trinity College, Cambridge, I embarked on board the yacht Titania the same evening.

The Captain immediately set sail, called off Orotava the next day, September 27, for the instruments and baggage, and has now safely brought them back to England after an absence of 117 days. Of these, 36 have been spent at sea, 18 in the low lands of Tenerife, 37 at the height of 8,870 feet, and 26 at the height of 10,900 feet.

C. PIAZZI SMYTH, Astronomer Royal for Scotland.

UNITED STATES SCREW STEAM-SHIPS.

Our scientific contemporary, the Mechanics' Magazine, supplies in the last number some very important particulars respecting the new class of steamfrigates, the introduction of which it is supposed by some will furnish a new era in war ships. It is the custom-and one not to be despised-of our Transatlantic cousins, whenever they have anything particularly striking belonging to them, to send it across to the old country to be admired. If we remember aright, they did this in 1810, or thereabouts, with their, at that time, monster frigate the Constitution. So proud, however, and flushed with victory were the Britishers, that they disdained the new creation of their humble relatives. Eighteen-pounder frigates of 1,000 tons were then looked upon, on this side of the water, as the ne plus ultra of single-decked ships; and the long 24pounders mounted on a deck near seven feet in height, were deemed unworthy of imitation. Experience proved otherwise. The thick-sided Yankee frigates encountered our comparatively fragile craft, and soon demonstrated their superiority. John Bull profited by the humiliating lesson, and has by degrees endeavoured to keep in advance rather than upon the heels of improvement in naval architecture. The rod has, however, had to be applied occasionally, but it has had a good effect, and the schoolmaster ought not to be condemned. Three years ago the maximum dimensions of our frigates was 2,400 tons; and their extreme length about 220 feet. The screw propeller, however, soon proved that additional length was required, and ships were lengthened, first at the bow, then in midships, and of late the architectural department seems to have come to the determination of going the entire animal. Jonathan, not to be outdone, has rivalled, if he has not surpassed, British ideas on this head; and having completed one out of five frigates has, according to his wont, sent her hither to astonish our weak minds.

The Merrimac has been for some time at Southampton, and her Captain and officers, with the accustomed courtesy of American gentlemen, have done all in their power to display their ship to all who have had the curiosity to go on board. Among the visitors may be reckoned a contributor to the Mechanics' Magazine, and we have much pleasure in availing ourselves of the details he has supplied respecting this new ship:

The principal dimensions of the five frigates [Merrimac, Wabash, Minnesota, Roanoke, and Colorado] are nearly alike, and may be taken as follows: Length on keel, 250 feet; length on load water line, 260 feet; length over all, 300 feet; breadth extreme, 51 ft. 4 in.; breadth moulded, 50 ft. 2 in.; depth of hold (to gun deck), 26 ft. 4 in.; draught of water forward, 23 ft. 6 in.; draught of water aft, 24 ft. When the vessel is at her load line, the heights of the gun deck ports above the water are, amidships, 9 ft., and forward and aft, 12 ft. or thereabouts. The height from her gun deck to the lower side of her spar deck beans, is 6 ft. The height of her bulwarks when the hammocks are stowed, is 8 ft. 8 in. Her gun deck ports are 3 ft. 8 in. long, and nearly 8 ft. 6 in. apart. Her load displacement is estimated at 4,000 tons.

The Merrimac was designed by Mr. Lenthall, and built by Mr. Delano, the master shipwright of the Navy-yard at Boston. Her frame is of live oak, crossed on the inside with two sets of diagonal iron plates. She is also strengthened by similar plates on the outside at bow and stern. Her planking is of oak, and decks fir. The large wooden knees to some extent interfere with the beauty of her appearance inboard. But she is a very roomy and handsome ship, and the appearance of her main deck is unsurpassed. The

Merrimac is ship rigged, and spreads 56,629 yards of canvas, or about the quantity of our own first-class frigates.

The armament of this frigate is thus described:

She is pierced for sixty guns, but if she were actually to carry that number, they would have to be of a lighter calibre than those now on board of her. Her present armament is as follows:-On her upper deck there two pivot guns, each weighing nearly 5 tons, and of 10 inches bore, and fourteen 8-inch guns, each weighing rather more than 3 tons; on her gun deck there are twenty-four 9-inch guns, each weighing nearly 4 tons. The whole of these guns, forty in all, are primarily intended to be served with hollow shot or shell. She might carry a few additional 9-inch guns on the main deck with perfect convenience. Her gun carriages on the main deck are similar to those used in the French Navy. They have, however, but two trucks each, at the ship's side end of the carriage.

So far the American frigate presents very formidable features, and, without doubt, such a ship would prove an awkward customer to any of our sailing line-of-battle ships; but that she would be terrible to a screw ship is very questionable. Our contemporary goes on to say,

She has two cylinders, 72 inches in diameter, and 3 feet stroke. These are placed close to the shaft, on opposite sides of it, leaving room only for the crank. She is fitted with four of the vertical tubular boilers patented by Mr. Martin, Engineer-in-Chief of the United States Navy. The boilers are of iron with brass tubes. The greatest speed ever attained by the Merrimac under steam alone was seven knots per hour, and this was under very favourable circumstances. Her average steaming speed is much less than this.

Now it cannot be doubted that the armament and great bulk of this frigate, of near 3,500 tons, would sink into insignificance before the well plied raking broadsides or occasional plumping shot from such ships as the Imperieuse, Euryalus, or any other of our large class screw frigates, all of whom steam with ease from ten to twelve knots an hour. They would go round the Merrimac as a cooper would round a cask, and plant a shot here and there with great effect, and with impunity to themselves. Speed is as needful as heavy metal; and unless a ship is cased with impenetrable plates, her success in action must principally depend upon the celerity of her evolutions. We shall see how far the engineering abilities of our cousins are likely to vie with those of the Watts on this side the ocean, by their further attempts at improvement; but hitherto we do not find them in the ascendency in that particular branch.

But the prowess of the United States Navy is not to depend upon the large frigates. A new class of corvettes is in course of construction, one of which, the Niagara, is in an advanced stage. This, the first of the race, is constructed by Mr. Steers, the naval architect, who astonished the yachting world by his America. Without wishing to detract from Mr. Steers' admitted merits we may say, by the way, that we consider the stunning success of the schooner to have been occasioned by other elements than the designer's art. The sailmaker and the sailors had quite as much to do with the victory obtained by the America as Mr. Steers had-the proof of which has since been made apparent by the great falling off in his vessel's performances under less skilled management. The Niagara may, however, be a fresh and more convincing instance of his skill. Our contemporary says,

The principal dimensions of the Niagara are as follows:-Length on load water line, 328 ft. 10 in.; over all, 345 ft.; breadth extreme, 55 ft.; moulded, 53 ft. 8 in.; depth of hold to spar deck, 51 ft. 3 in.; draught of water 26 ft. Her ports are 15 feet above the load water line. Her height between decks, is 7 ft. 3 in. to the under side of beams. Her displacement at 23 ft. draught, is 5,440 tons. Her frame is of live oak, and crossed on the outside with two sets of diagonal iron plates. Having a very fine run, she is, of course, weak NO. 11.-VOL. XXV.

4 L

at her quarters, in consequence of which, Mr. Steers has fitted on each side a large 2-inch iron stay or brace, which lies along the upper deck beams, and passing through the deck below, steps upon the stern post. It may as well be added, that when she is docked, it is thought necessary by Mr. Steers to brace her two sides together at about the turn of the bilge, by means of a chain, which passes over a frame or saddle, which is set up by wedges. She is rigged like the Merrimac and others.

The Niagara carries 12 guns, 5 of a side, and two pivot guns, each of them 11 inches in the bore, and weighing upwards of 7 tons. All the guns are mounted on pivoted carriages, and the hroadside ports have consequently to be very large-9 ft. long and 4 ft. high. The Niagara is intended to be fast, and, being furnished with longe range guns, is supposed to have the power of annoying and injuring an enemy while she herself keeps out of the range of her enemy's guns. The engines, built by Messrs. Pease and Murphy, New York, are similar to those of the Merrimac, but she has three cylinders, each 72 inches diameter. The boilers are four in number, 11 feet long, 21 feet wide, and 15 feet high. Like those of the frigate, they are Mr. Martin's vertical tubular.

Without in the least wishing to indulge in braggadocio we cannot avoid saying that these additions to the United States Navy do not in the least repress any warlike desires we might have before entertained. The fleetness of our new corvettes-such as Pearl, Pylades, Satellite, and some others- would, should they ever chance to come into collision with the Niagara, go far 10wards neutralising the heavy armament of that ship; and if the fighting deck of the Niagara should be as stated "15 feet above the water line," we have considerable doubts as to the amount of steadiness she would evince if encountered in a sea way. At the same time we freely award to our neighbours, whose amicable feelings we value much more than we dread their wrath, the highest praise for that Anglo-Saxon zeal which stimulates their very laudible endeavours to hold their own in the scale of nations, and we hope to see the same commendable attributes manifested on this side of the Atlantic. United Service Gazette.

NAUTICAL NOTICES.

VIGIA MAKING.

The Report of a rock above water to the S.W. of the Cape Verds seems so "very like a whale," that it is entitled to be classed under the head of "Vigia Making."

Lloyds', 23rd September, 1856.

Sir, I am instructed, on the part of the Committee for managing the affairs of Lloyd's, to transmit to you, for the information of the Lords Commissioners of the Admiralty, the accompanying copy of a letter, and its inclosure, received from the Agents to this Establishment at Scilly, relative to a rock passed in lat. 14° 29′ N. and long. 26° 30′ W. by the barque Mandarin, Tregarthen, from Liverpool to San Francisco, reported not to be marked in the chart. I have, &c.,

The Secretary of the Admiralty.

G. HALSTED, Secretary.