length in the Repertory, and not one word occurs therein, as to any other mode of lifting or lowering the table than by the clumsy levers and wheel work described and claimed.

Mr. Ellis has, within a short time, erected a large turn-table upon the Drogheda Railway-labelled duly on top in iron letters, "Eilis's Patent"-but to my surprise, I observe he has abandoned all his own arrangements, and adopted, without acknowledgment, my method of supporting and lifting the table, by making the lower pivot the cylinder of an hydraulic press, as figured and fully described by me in your Magazine for August 20, 1842, No. 993. The arrangements are absolutely identical. This cool piece of dishonesty and plagiarism, I think deserves showing up; and allow me to ask, whether a party, labelling an article as his patent, for which he has none, as in the present case, is not liable to a rather serious fine, under Lord Brougham's amendment to the patent law?

The table in question would act well, if the workmanship of the hydraulic part of it were as good as the design, which is not the case. As to the combination of the turn-table and weighing machine, however, there never was a more prepos terous idea, as the experience of one on the Drogheda line sufficiently proves. The principle of every good balance, of whatever size, should be that of minimum weight in proportion to the load to be weighed. One might have fancied, that the heavier it could be made the better, from the load of levers and bars, and so forth, under which these affairs groan. Yours obediently, ROBERT MALLET.

Dublin, October 6, 1845.

PROFESSOR MORSE'S ELECTRIC

TELEGRAPH.

[Extract from a letter addressed by Professor Morse to the Secretary of the United States Treasury.]

That which seemed to many chimerical at the time, is now completely realized. The most sceptical are convinced; and the daily and hourly operations of the telegraph, in transmitting information of any kind, are so publicly known, and the public feeling in regard to it so universally expressed, that I need here only give a few instances of its action, further to illustrate its character.

The facts in relation to the transmission of the proceedings of the Democratic Convention at Baltimore, in May last, are well known, and are alluded to in my report to the department, June 3, 1844. (House Doc. No. 270, 28th Cong., 1st sess.) Since the adjournment of Congress in June last, and during the summer and autumn, the telegraph has been in constant readiness for operation, and there has been time to test many points in relation to it, which needed experience to settle.

For more, now, than eight months, the conductors for the telegraph, carried on elevated posts for forty miles, have remained undisturbed from the wantonness or evil disposition of any one. Not a single instance of the kind has occurred. In several instances, indeed, the communication has been interrupted by accidents, but then only for a very brief period.

One of these was by the great fire in Prattstreet, Baltimore, which destroyed one of the posts, and consequently temporarily stopped the communication; but in two or three hours the damage was repaired, and the first notice of the accident, and all the par-ticulars, were transmitted to Washington by the telegraph itself.

Another instance of interruption was occasioned by the felling of a tree, which accidentally fell across the wires, and at the same time across the railroad track-stopping the cars for a short time, and the telegraphic communication for two hours.

Excepting the time excluded by these, and two or three other similar accidental interruptions, and which, during seven months of its effective existence between the two cities, does not altogether amount to more than twenty-four hours, the telegraph has been either in operation, or prepared for operation, at any hour of the day or night, irrespective of the state of the weather.

It has transmitted intelligence of the greatest importance. During the troubles in Philadelphia the last summer, sealed despatches were sent by express from the mayor of Philadelphia to the President of the United States. On the arrival of the express at Baltimore, the purport of the despatches transpired; and while the express train was in preparation for Washington, the intelligence was sent to Washington by telegraph, accompanied by an order from the president of the railroad company to prevent the Washington burden train from leaving until the express should arrive. The order was given and complied with. The express had a clear track; and the President and the cabinet being in council, had notice both of the fact that an express was on its way with important despatches for them,

and also of the nature of the despatches; so that, when the express arrived, the answer was in readiness for the messenger.

In October, a deserter from the United States ship Pennsylvania, lying at Norfolk, who had also defrauded the purser of some 600 or 700 dollars, was supposed to have gone to Baltimore. The purser called at the telegraph office in Washington, stated his case, and wished to give notice in Baltimore, at the same time offering a reward for the apprehension of the culprit. The name and description of the offender's person, with the offer of the reward, were sent to Baltimore, and in ten minutes the warrant was in the hands of the officers of justice for his arrest; and, in half an hour from the time that the purser preferred his request at Washington, it was announced from Baltimore by the telegraph, "The deserter is arrested; he is in jail. What shall be done with him?"

To show the variety of the operations of the telegraph, a game of drafts and several games of chess have been played between the cities of Baltimore and Washington, with the same ease as if the players were seated at the same table. To illustrate the independence of the telegraph of the weather and time of day, I would state that, during the severe storm of the 5th of December, when the night was intensely dark, the rain descending in torrents, and the wind blowing a gale, it seemed more than ordinarily mysterious to see a company around a table in a warm retired chamber on such a night in Washington, playing a game of chess with another company similarly situated in Baltimore-the darkness, the rain, and the wind being no impediment to instantaneous communication.

In regard to the quantity of intelligence which may be sent in a given time, it is perfectly safe to say that thirty characters can be transmitted in a minute by a single instrument; and, as these characters are conventional signs, they may mean either numbers, letters, words, or sentences.

As an illustration of this point, I will state that nearly a whole column (more than seven-eighths) in the Baltimore Patriot was transmitted in thirty minutes-faster than the reporter in Baltimore could transcribe.

This fact bears upon the ability of producing a revenue from the telegraph; and I would suggest the propriety of permission being granted by Congress to the department to adjust a tariff of charges on intelligence sent by telegraph, at such a rate of postage as shall at least return to the treasury the interest of the capital expended in the first construction and the after maintenance of the telegraph.

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In the absence of experience, the expense necessary to construct and to maintain a system of electro-magnetic telegraphs was thought to be so great as to present a formidable, if not an insurmountable, obstacle to its adoption. But the experiment already made for forty miles has shown that the electro-magnetic telegraph is far from being expensive either in its first construction or after maintenance, especially when its vast superiority over the old system is taken into consideration.

To make this more clear, I give an abstract both of the expenses and capacities of the ordinary visual telegraphs in some of the European countries.

In England, the semiphore telegraph established between London and Portsmouth (a distance of seventy-two miles) is maintained by the British Government at an average expense of 3,4057., or 15,118 dollars per annum. From a return (vol. 30, 1843, accounts and papers of House of Commons,) of the number of days during which the telegraph was not available on account of the weather during a period of three years, it appears that there were in that time 323 days in which it was useless, or nearly one year out of three! But by a return made to the Admiralty of the number of hours in the day appointed for working the telegraph, it appears that the hours appointed for the year are-from the 1st of October to the 28th of February, from 10 o'clock A.M., to 3 P.M.-5 hours; from the 1st of March to the 30th of September, from 10 o'clock A.M., to 5 P.M.-7 hours.

Average number of hours per day in the most favourable weather, 6 hours!

Deducting one year from the three for unavailable days, the average time per day for the three years would be but 4 hours. So that for the use of their telegraph for seventy-two miles, and for only 4 hours in the day, the British Government expend 15,118 dollars per annum.

The French system of telegraphs is more extensive and perfect than that of any other nation. It consists at present of five great linės extending from the capital to the extreme cities of the kingdom, to wit:

The whole extent, then, of the French lines of telegraph is 1,474 miles, with 519 stations; and, (if the estimate for six stations, at an average cost of 4,400 francs, is a criterion for the rest) erected at a cost of at least 880 dollars each-making a total of 456,720 dollars.

The electro-magnetic telegraph, at the rate proposed in the bill, (to wit, 461 dollars per mile, and which it should be remembered will construct not one line only, but six,) could be constructed the same distance for 619,515 dollars-not one-third more than the cost of the French telegraphs. Even supposing each line to be only as efficient as the French telegraph, still there would be six times the facilities for not one-third more cost. But when it is considered that the French telegraph, like the English, is unavailable the greater part of the time, the advantages in favour of the magnetic telegraph become more obvious.

An important difference between the two systems is, that the foreign telegraphs are all a burden upon the treasury of their respective countries; while the magnetic telegraph proposes, and is alone capable of sustaining itself and of producing a revenue.

Another difference in the two systems is, that the stations in the foreign telegraphs must be within sight of each other: a fact which bears essentially on the cost of maintenance. The French telegraph requires for the distance of 1,474 miles, no less than 519 stations-averaging one for about every three miles. The number of stations of the magnetic telegraph, on the contrary, is optional. The two stations (one only at Baltimore and one at Washington) show that they may be at least 40 miles apart, and there is no reason to doubt, from experiments I have made, that 100 miles, or even 500 miles, would give the same results. In the maintenance, therefore, of stations, the magnetic telegraph would require but 15 stations, (assuming that 100 miles is the utmost limit of transmission between two stations, which is not probable ;) while the French requires 519 for the same distance.

When to this are added the facts, that the magnetic telegraph is at all times available, at every hour of the day or night, irrespective of weather: that, in comparison with the visual telegraphs, it communicates more than a hundredfold the quantity of intelligence in the same time; that it is originally constructed at a less cost (all things considered;) that it is maintained for less; and that it is capable, by a rate of charges for transmitting intelligence, not only of defraying all its expenses, but, if desired, of producing a revenue; I may be permitted to hope that, when these great advantages

In the autumn of 1842, at the request of the American Institute, I undertook to give to the public in New York a demonstration of the practicability of my telegraph, by connecting Governor's Island with Castle Garden-a distance of a mile; and for this purpose I laid my wires properly insulated beneath the water. I had scarcely begun to operate, and had received but two or three characters, when my intentions were frustrated by the accidental destruction of a part of my conductors by a vessel, which drew them up on her anchor and cut them off In the moments of mortification, in a sleepless night, I devised a plan for avoiding such an accident in future, by so arranging my wires along the banks of the river as to cause the water itself to conduct the electricity

A, B, C, D, are the banks of the river; IN P, are the batteries; E, is the electromagnet; w w, are the wires along the banks, connecting with copper plates f, g, h, i, which are placed in the water. When this arrangement is complete, the electricity generated by the battery, passes from the positive pole P, to the plate h, across the river, through the water to plate i, and thence around the coil of the magnet E, to plate f; across the river again to plate g, and thence to the other pole of the battery N. The numbers 1, 2, 3, 4, indicate the distance along the bank, measured by the number of times of the distance across the river.

The distance across the canal is 80 feet; on August 24th, the following were the results of the experiments :

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Showing that electricity crosses the river, and in quantity in proportion to the size of the plates in the water. The distance of the plates on the same side of the river from each other, also affects the result. Having ascertained the general fact, I was desirous of discovering the best practical distance at which to place my copper plates; and, not having the leisure myself, I requested my friend, Professor Gale, to make the experiments for me. As the result of these experiments, it would seem that there may be situations in which the arrangements I have made for passing electricity across the rivers may be useful, although experience alone can determine whether lofty spars, on which the wires may be suspended, erected in the rivers, may not be deemed the most practical. The experiments made were but for a short distance; in which, however, the principle was fully proved to be correct.

It has been applied, under the direction of my able assistants, Messrs. Vail and Rogers, across the Susquehannah river, at Havre-de-Grace, with complete success-a distance of nearly a mile.

2 ft.

I have as yet said nothing on the telegraph as a mighty aid to national defence. Its importance in this respect is so obvious, that I need not dilate. The importance generally to the Government, and to the country, of a perfect telegraphic system, can scarcely be estimated by the short distance already established between Baltimore and Washington; but when all that transpires of public interest at New Orleans, St. Louis, Pittsburg, Cincinnati, Buffalo, Utica, Albany, Portland, Portsmouth, Boston, New York, Philadelphia, Baltimore, Washington, Norfolk, Richmond, Charleston, Savannah, and at all desired intermediate points, shall be simultaneously known in each and all these places together,-when all the agents of the Government in every part of the country are in instantaneous communication with headquarters, when the several departments can at once learn the actual existing condition of their remotest agencies, and transmit at the moment their necessary orders to meet any exigency, then will some estimate be formed both of the powers and advantages of the magnetic telegraph.

This stone is produced from a quarry near Leeds, in Yorkshire. It possesses many advantages, which particularly recommend it for use in the erection of private or public buildings, intended to combine solidity and splendour. It is as durable as granite, absorbs scarcely any moisture, presents a beautiful surface, and is not liable to discoloration by the influence of the atmosphere. A sample of it has been subjected to the test of MM. Vicat, Billandel and Courard, by Dr. Ure, who has expressed a most conclusive opinion in its favour. Among other things, the Doctor states, that, "it is, in fact, a siliceous grit, so closely aggregated, and so devoid of fissures, as to bid defiance

to the tooth of time, and, therefore, admirably adapted for every architectural purpose, where strength and durability are the great requisites."

To the above may be added, that, from its great capability of resisting heat, it is an excellent fire-stone, and consequently, adapted for many chemical purposes. These few remarks are founded upon testimonials from various practical and eminent authorities, and have been penned with a view to bring so valuable an acquisition into more general notice, believing we are thus consulting the public advantage as much as the individual interest of the proprietors.-From a Correspondent.

tions you have lately made therein as to my claims of priority to Mr. Nasmyth

in the invention of the method of obtaining vacuum for use on atmospheric railways by the direct action of steam. You say clearly Mr. Nasmyth is the first inventor because he was the first to publish what I so carefully kept secret," &c. In this you appear to me to lose sight of the distinction between the first inventor in the eye of the patent law and the first inventor, de facto, the man who is entitled to the right of credit for the invention, although positively deprived of the power of being remunerated by it. Thus, for instance, it is well known that Watt invented the crank motion of the steam engine, although it was patented by a faithless workman who stole his idea, and who became the inventor in the eye of the law, and whose monopoly obliged Watt to patent the sun and planet motion.

Now the facts of the present case stand thus: I had communicated my plans for vacuum by direct action of steam to several persons in this country LONG prior to Mr. Nasmyth's patent, and I am also in a position to prove that I had communicated my plans to at least four persons resident in England, not consulted for the sake of maturing invention or the like, long before the date of his patent; and I may further state now, that prior to his specifying, Mr. Nasmyth and I compared notes as to our respective views, which were found singularly coincident.

I do not know what amount of publicity, or communication, constitutes legal publication of an invention, but I presume the above does, and if so, I am first inventor, even in the eye of the law; and, should this be so, of course, the patent is worth nothing. I have, however, neither wish nor intention of depriving Mr. Nasmyth, whose acquaintance I honour, and whose ingenuity I admire, of the fruits of his, as I believe, independent re-invention of what I had before him also independently discovered-but I do claim the merit (if any there be) of first inventor; and although I cannot expect that Mr. Nasmyth should destroy his own patent by admitting this,-yet I shall be curious to see any proof advanced by him that he ever entertained any thoughts of the use of direct-acting steam for procuring vacuum for atmospheric railways, prior to the date of my

Report on the subject, or even six months before the sealing of his patent. Silence in this case must indicate that Mr. N. is too candid to attempt an unsupportable case; but if such proofs are proposed being adduced, I shall be ready to lay mine before the public, and let the patent bide the consequences.

I have only to add, as to one other of your remarks, that you are quite right in assuming that the sealed packet before the Royal Irish Academy alluded to by me, contained my three reports, as lately printed by Mr. Weale, word for word. I am, Sir, yours obediently, ROBERT MALLET.

Dublin, October 7, 1845.

PREVENTION OF RAILWAY ACCIDENTS.

Major-General Pasley, the Government Inspector of Railways, accompanied by Dr. Melson and Mr. M'Connell, superintendent of the locomotive department of the Bristol and Birmingham railway, recently visited Shadwell-street Mills, Birmingham, for the purpose of witnessing Mr. George Heaton's experiments with regard to the prevention of railway accidents. The following results have since been communicated by Dr. Mel

son:

The series of experiments was performed by means of a model, having a shaft or axle, 4 feet 8 inches in length, and three quarters of an inch in diameter, which had a steel rod 3 feet 1 inch in length, and 5-16 inches thick, (No. 1 wire gauge,) passing through each end of it-the axle representing in width the narrow-gauge rail, and the steel rods the wheel of a carriage. Near the extremities of these steel rods were attached one pound weights, to give momentum, a small projection being left at each end for the purpose of the attachment of small weights, of three ounces each, by which the wheels may be placed in balance, or variously out of balance, at the pleasure of the experimenter. To give motion to these wheels a string is wound around the centre of the axle until there is a sufficient length to allow a weight attached to the end of it to fall 6 feet 1 inch. The whole is attached to a frame-work, which renders apparent the amount of oscillation observable under the various conditions of balance or want of balance, the weight attached to the string representing the moving force.

Both

EXP. 1.-Moving force, 12 lbs. ends of the transverse rods in perfect balance, each end carrying 1lb. 3 oz. The wheel revolved 139 times in 1 min. 55 sec. Motion-Equable.