It is necessary that a mandrel should fit so accurately, as to bite on the inner surface with a force sufficient to counteract that of the tool, and, in the ordinary mode, the same mandrel cannot be used for two pieces which are of different diameters. Consequently, in many engineering establishments, a stock of mandrels is kept, amounting to 600 or 700. Mr. Hick purposes to do the same work with eight sizes of the mandrel, from one inch and a quarter to ten inches. He effects his object by having the spindle of the mandrel shaped on the frustrum of a cone, on the face of which are four dove-tail grooves to receive wedges, the under faces of which have the reverse inclination of the cone, so that the lines of their outside faces are always parallel with the axes of the mandrel. A nut is screwed on the spindle, which acts on the wedges through the medium of a conical cup, which drives them up to their bearings inside of the work.

Manchester and Liverpool Plate Glass Company.

Mech. Mag.

A general meeting of the shareholders of this company was held on Friday, the 28th ult., at the works, Sutton, near St. Helen's. These extensive works are now in full operation, and the shareholders were gratified by viewing the various processes of the manufacture. Six large plates of glass were cast in a surprisingly short space of time, and, apparently, with great skill; indeed, the competition of the new and old companies seems likely to lead to considerable improvements in the production of this beautiful commodity. Upon this occasion, amongst a great number of very large plates of glass, there was shown one plate of a size that, we understand, has been rarely equalled in this or any other country; it was thirteen feet long by eight feet wide, and apparently free from imperfections.

Railways-Important Invention.

Mining Journal.

We copy the following paragraph from the Sheffield Iris, and, at the request of a correspondent, append a letter which has since been addressed to the editor of that paper, having reference to the invention.

"We understand there will be placed upon this railway, in a few days, an engine patented by a gentleman of this town, which possesses many advantages over any other. All the six wheels are connected by a strap either of hemp or leather, thereby presenting six points of adhesion or friction to the rails, instead of two, which will secure a uniformity of speed in all weather. It is expected to move double the weight, at the same velocity, to any other engine of same weight and capacity of cylinder. It will also greatly diminish the expenses of repairing the road; for each of the engines now in use weighs, when the boiler is charged with water, twelve tons, nearly the whole of which to ensure progressive motion, is placed upon the two driving wheels. But the patent engine having the weight divided equally between each wheel (every one being a driver,) it is obvious that the one engine is striking the rail with a twelve ton hammer, while the other is gently tapping it with four. Not only great speed, but great regularity also, are expected from railways, both of which will be insured by this invention. It will also acquire its speed, and be stopped, sooner than the other engine."

Ibid.

Railways in England.

There are now in England 682 miles of railway completed and in operation, and it is expected that in the course of the present year 650 miles additional will be completed, making altogether 1313 miles of railway, which will be brought into operation before the end of 1840. There will then remain for subsequent completion in England 413 miles, the entire number of miles for which railway Acts have been passed being 1726 miles. The amount to be raised by calls for railway purposes during the present year is calculated to be 5,908,5007., a sum considerably less than was called up during the past year of depression and suffering. The amount remaining to be called for, after 1840, is 3,865,000l., which will complete the capital authorised to be raised for railways in England by Acts of Parliament passed up to the close of last session.

The "Archimedes."

Ib.

We have of late heard frequent inquiries made respecting the important substitution of the screw for paddles, exhibited in the Archimedes, of which we gave an account several months ago. The vessel is now at Dover, competing, in an amicable way, with the Government packets at that station, in which she has been very successful. The saving of fuel by this invention is a matter of great importance, and we understand that in all the trials, the screw has never once been out of order. The Archimedes, it is said, would have made any difficult passage, such as that from Liverpool to Dublin, during the winter, in as little or less time than the best steamer upon the station, and with half the fuel, because she would have often gone quicker by sailing than others by steaming. She is stiff under canvass, and sails beautifully-the screw being no impediment. The inactivity of the company for so many months was occasioned by the repeated accidents to the engine, and not by any difficulties about the invention itself.

Ib.

Wealth in Russia.

M. de Tiszkiewicz, the richest landholder in Russian Lithuania, died a short time since. The St. Petersburgh papers inform us that he left to his three sons 2,000 villages, containing more than 60,000 serfs, and in ready money 10,000,000 crowns, and that it was this gentleman who was said to have refused the hand of his daughter to Duke Alexander of Wurtemberg, who afterwards married the Princess Marie d'Orleans. His daughter has since married Prince Sapicha, and had 2,000,000 of crowns for her dowry. A letter from St. Petersburgh says "This gentleman's property comprised 46 extensive domains, on which there are 20,000 families of peasantry, reckoning in them 60,000 males. In money he possessed 56,000,000 Polish florins, equal in French money to 21,600,000 francs. He had had six children, of whom three sons, besides his daughter, survive him. The eldest, according to the laws of Lithuania, inherits the whole of this immense wealth. He, however, has assigned one-fourth to be equally divided between his two brothers.

Galignani's Messenger.

Angles reckoned to the right or

in an inverting telescope.

LUNAR OCCULTATIONS FOR PHILADELPHIA, westward round the circle, asseen SEPTEMBER, 1840.

For direct vision add 180°