MR. CURTIS'S ACOUSTIC INVENTIONS.

The application of acousties to the purposes of civilisation has been very culpably neglected-even to the loss of what was known and practised centuries ago. Dr. Reid has had the merit of calling public attention to the subject, in as far as relates to the construction of buildings, in his public lectures and his evidence before the Commons' Committee on the New Houses of Parliament.* We have now to call the attention of our readers to another branch of the science, namely, the conveyance of sound to great distances by acoustic tunnels. "What the telescope is to the eye, acoustic tunnels would be to the ear.

It ap pears no more wonderful that we should be able to hear at the distance of five or six miles, than that we should be enabled to see objects at that distance by the telescope, as distinctly as if we were within a few yards of them."+ Acting on this intelligent view of the subject, Mr. Curtis, one of the most skilful aurists of the day, has been led to the invention of an acoustic chair, of which an engraving appears on our front page, and which is thus described in his "Treatise on the Ear."+

"The acoustic chair is intended for the benefit and use of the incurable deaf. A somewhat similar chair was constructed in 1706 by M. Duguet, who likewise invented some acoustic tubes. But one of the great advantages possessed by my chair over his consists in this, that the person sitting in it hears at the opposite side from that at which he is addressed; thus avoiding the unpleasant and injurious practice of the speaker coming so close as to render his breath offensive, and, at the same time, detrimental to the organ of hearing, by causing a relaxation of the membrane of the tympanum. This is an effect commonly produced by the use of short flexible tubes,§ no less than by hearing

See Mechanics' Magazine, vol. xxv. p. 69. +" Dick's Christian Philosopher."

A Treatise on the Physiology and Pathology of the E r. By John Harrison Curtis, Esq., Aurist to his Majesty, &c. Sixth Edition. London: Longman and Co.

Instances are on record in which very baneful and injurious effects have resulted from the practice of speaking into the ear, more especially where the breath of the person is tainted. One ease I may inention, which is related by Lord Herbert. Cardinal Wolsey, he tells us, towards the latter part of his life, was in the habit of whispering into the ear of his sovereign, Henry VIII.; and the serious indisposition of the king has been many times attributed to this cause, and certainly not without reason.

trumpets, which latter are as often, perhaps, employed for speaking through, as for the purpose for which they were designed; and it is a certain fact, that many persons, after having used a trumpet for half an hour, are quite deaf, from the action of the breath impelled against the membrana tympani.

"My acoustic chair is se constructed, that, by means of additional tubes, &c., the person seated in it may hear distinctly, while sitting perfectly at ease, whatever transpires in any apartment from which the pipes are carried to the chair; being an improved application of the principles of the This speaking-pipes now in general use. invention is further valuable, and superior to all other similar contrivances, as it requires no trouble or skill in the use of it; and is so perfectly simple in its application, that a child may employ it with as much facility, and as effectually, as an adult. It is, moreover, a very comfortable and elegant piece of furniture.

"This chair is of the size of a large library one, and has a high back, to which are affixed two barrels for sound, so constructed as not to appear unsightly, and at the extremity of each barrel is a perforated plate, which collects sound into a paraboloid vase from any part of the room. The instrument thus contrived gathers sound, and impresses it more sensibly by giving to it a small quantity of air. The convex end of the vase serves to reflect the voice, and renders it more distinct. Further, the air enclosed in the tube being also excited by the voice, communicates its action to the ear, which thus receives a stronger impression from the articulated voice, or indeed from any other sound. What first induced me to invent this chair was the fatigue I sometimes experienced in talking to deaf persons.

"By means of sufficient tubes, this chair might be made to convey intelligence from St. James's to the Houses of Lords and Commons, and even from London to the King at Windsor. Marvellous as this may seem, the idea is not a novelty; it is but another confirmation of the saying of Solomon, that there is nothing new under the sun. M. Itard, in his excellent work on the ear, tells us that Aristotle (who was physician to Alexander the Great) invented a trumpet for his master, which was capable of conveying orders to his generals at the distance of 100 stadia, equal to rather more than 12 miles. And I may remark, bearing in mind, too,

"This is mentioned in a MS. found some time since in the Vatican, entitled Secreta Aristotelis ad Alexandrum Magnum, and is stated to have been five cubits in diameter. Sir John Morland's speaking-trumpet only conveyed sound on the open sea for a distance of two miles, even when the wind was favourable.

that both Alcmeon and Hippocrates are said to have invented ear-trumpets, that the an*cients do not seem to have been so ignorant of acoustics as some in our day have repre*sented them."

In the engraving, A is the acoustic barrel, B the acoustic conductor, C the tube to be applied to the ear, and D the tunnel by which the sound is to be conveyed. This chair is only shown adapted for hearing; to convey sound from it to a distance, there should be another conductor, and a mouth-piece to speak through.

We understand that Mr. Curtis has at present before the Lords of the Treasury a plan for conveying messages from one Government-office to another, upon the same principle as the chair; as, for instance, between the various official departments in Whitehall, from the Horse Guards to the Mansion House, &c.

In the work which we before quoted (the "Christian Philosopher,") are some very interesting remarks upon the subject, which we subjoin :

Some experiments have lately (1828) been made by M. Biot, on the transmission of sound through solid bodies, and through air, in very long tubes.' These experiments were made by means of long cylindrical pipes, which were constructed for conduits and aqueducts, to embellish the city of Paris. The pipes by which he wished to ascertain at what distance sounds are audible, were 1,039 yards, or nearly five furlongs, in length. M. Biot was stationed at the one end of this series of pipes, and Mr. Martin, a gentleman who assisted in the experiments, at the other. They heard the lowest voice, so as perfectly to distinguish the words, and to keep up a conversation on all the subjects of the experiments. I wished,' says M. Biot, 4.to determine the point at which the human voice ceases to be audible, but could not accomplish it: words spoken as low as when we whisper a secret in another's ear, were heard and understood; so that not to be heard, there was but one resource, that of not speaking at all. This mode of conversing with an invisible neighbour, is so singular, that we cannot help being surprised, even though acquainted with the cause. Between a question and answer, the interval was not greater than was necessary for the transmission of sound. For Mr. Martin and me, at the distance of 1,039 yards, this time, was about 5 seconds.' Reports of a pistol fired at one end, occasioned a considerable 'explosion at the other. The air was driven out of the pipe with sufficient force to give

the hand a smart blow, to drive light substances out of it to the distance of half a yard, and to extinguish a candle, though it was 1,039 yards distant from the place where the pistol was fired. A detailed account of these experiments may be seen in Nicholson's Phil. Jour., for October, 1811. Don Gautier, the inventor of the Telegraph, suggested also the method of conveying articulate sounds to a great distance. He proposed to build horizontal tunnels, widening at the remoter extremity, and found that at the distance of 400 fathoms, or nearly half a mile, the ticking of a watch could be heard far better than close to the ear. He calculated that a series of such tunnels would convey a message 900 miles in an hour.

"From the experiments now stated, it appears highly probable, that sounds may be conveyed to an indefinite distance. If one man can converse with another at the distance of nearly three quarters of a mile, by means of the softest whisper, there is every reason to believe, that they could hold a conversation at the distance of thirty or forty miles, provided the requisite tunnels were constructed for this purpose. The latter case does not appear more wonderful than the former. Were this point fully determined, by experiments conducted on a more extensive scale, a variety of interesting effects would follow, from a practical appli cation of the results. A person at one end of a large city, at an appointed hour, might communicate a message, or hold a conversation with his friend, at another; friends in neighbouring, or even in distant towns, might hold an occasional correspondence by articulate sounds, and recognise each other's identity by their tones of voice. In the case

of sickness, accident, or death, intelligence could thus be instantly communicated, and the tender sympathy of friends immediately exchanged. A clergyman sitting in his own room in Edinburgh, were it at any time expedient, might address a congregation in Musselburgh or Dalkeith, or even in Glasgow. He might preach the same sermon to his own church, and the next hour to an assembly at forty miles distant. And surely there could be no valid objection to trying the effect of an invisible preacher on a Christian audience. On similar principles, an apparatus might be constructed for augmenting the strength of the human voice, so as to make it extend its force to an assembled multitude composed of fifty or a hundred thousand individuals. In short, intelligence respecting every important discovery, occurrence, and event, might thus be communicated, through the extent of a whole kingdom, within the space of an hour after it had taken place."

Mr. Curtis has also invented various

instruments for the relief of the deaf. His telescope hearing-trumpet (see front page), forming a parabolic conoid, and shutting up into a small case for the pocket, is one of the most useful.

STEAM COMMUNICATION WITH INDIA.

Two years and a half have now elapsed since a Committee of the House of Commons recommended the immediate establishment of a line of steam-packets between England and India, by way of the Red Sea-and yet that object is as far as ever from being carried into effect. It was, as the event has shown, a most unfortunate circumstance that the same Committee also recommended the fitting out of an expedition to attempt a passage by the river Euphrates and the Persian Gulf, since the very activity and spirit with which that expedition was set on foot, seem to have exercised a benumbing influence on the less romantic but more certain plan; and the public mind ap pears to have been too much occupied with one expedition to India, to be able to take any interest in the furtherance of another. The Committee made another mistake; they recommended the House of Commons to grant 20,000l. in aid of the Euphrates enterprise-the House at once voted that sum-and Colonel Chesney was quickly on his way to the East; they also declared that a regular line of steam communication by way of the Red Sea ought forthwith to be established, at the joint charge of the Government and the East India Company, and left it to those two bodies to consider the details of the plan. What is the result? There has been plenty of time, and to spare, for a score of voyages, and nothing has been done. It would evidently have been far better had the House of Commons found the funds for setting the practicable scheme afloat, and referred the Euphrates, or merely experimental part of the business, to the long-winded consideration" of the Ministry and the lords of Leadenhall-street.

Now, however, that the Colonel's ex-pedition has proved a total failure, it is devoutly to be hoped that the rational and straightforward half of the Committee's recommendation will be attended to. It is nothing short of a disgrace to England that a regular communication

with its dependencies in Hindostan by the agency of steam is a thing still to seek; the delay which has taken place in effecting it is, indeed, absolutely astonishing. If public attention at home could be properly directed towards the importance and the practicability of the object, there is reason to hope that whatever difficulties stand in the way would quickly disappear. A few public meetings in the metropolis, and the leading commercial towns, are probably all that is required to overcome the vis inertia of the " powers that be," and give a due degree of life and vigour to the longdormant recommendation of the Commons' Committee. There is, at any rate, no want of enthusiasm at the other end of the Line; all India, British and native, may be fairly said to be unanimously in favour of the question, and the three presidencies have testified the sincerity of their feelings by subscribing largely to promote the object. Petitions to Parlia ment from that quarter are also ready for presentation at the opening of the ensuing session; and these would, of course, tell with redoubled effect if followed by others with a similar prayer from the leading cities and towns of " the home empire." To excite such a manifestation of opinion appears to be one of the chief objects of a well-timed pamphlet recently published, from the pen of Captain Grindlay, the London Agent to the Steam Committees of Calcutta and Madras ;* which is also valuable in another point of view, as presenting in a collected form all the facts relating to what has been done and is doing in furtherance of the grand design. It is to be hoped that the Captain will succeed in arousing the attention of the public towards it, of which there is little doubt, if he be backed, as he ought, by the periodical press.

Whether Government and the East India Company have ever given that consideration to the scheme which they were recommended to do by the Parliamentary Committee, cannot, of course, be known. If they have, the grand obstacle to their immediate adoption of the plan must have been the expense. It is admitted

* A View of the Present State of the Question as to Steam Communication with India; with a Map, and an Appendix, containing the Petitions to Parliament, and other Documents. By Captain Melville Grindlay. London: Smith, Elder, and Co. 1837. 8vo. pp. 99.

on all hands, that the returns to be looked for from passengers and postage will not equal the expenditure; and it is, therefore, a question of some interest to the parties on whom the burthen is to fall, what sum may be reasonably anticipated as the amount of the deficiency? In the appendix to the Madras memorial to the India Company a detailed estimate is entered into, from which it would appear that the estimates formerly made by the Company might (as suspected by the Commons' Committee) be greatly reduced in almost every particular; to so great an extent, in fact, as to diminish the probable charge on the Indian revenue to a fraction above 10,000l. per annum-a sum too small, it might well be supposed, to weigh long in the balance against a scheme whose advantages, immediate and prospective, are so immense, that, in the words of the late Governor-General, Lord William Bentinck, “they would be cheaply bought at any price." It is to be lamented that the estimate put forth by the newlystarted East India Steam Navigation Company should, in appearance at least, be so much at variance with this. The Company propose to effect a regular monthly communication with India, by the Red Sea route, on a sum of 65,0001. per annum being guaranteed to them; so that, at first sight, the Madras estimate, according to which the whole sum out of pocket would be little more than 20,000l., seems extravagantly low. It should be borne in mind, however, that the Madras Committee enter into the details of their estimate, which the Company do not-as well as that the latter include in theirs the expenses of the whole line, while the former confine their attention to the InIdian half, to which alone the resolution of the Committee as to the division of expense refers, the line to Alexandria being already established by Government, and proposed to be left in their hands; a fact apparently quite overlooked by the projectors of the new Company, although by no means without its importance.

The setting-up of this Company at the present juncture is perhaps a thing to be deprecated. Division has been the bane of the steam-communication project from the first. In India the rivalry of Bombay with the other presidencies, as a point of starting, has only been pro

ductive of an evil effect; and at home we have seen what has been the result of the House of Commons' Committees aim

ing at two things at once. What is now wanted is unanimity-" a long pull, a strong pull, and a pull altogether." The selection of Point-de-Galle, in the island of Ceylon, as a point of union, from which branch steamers may proceed, on the arrival of the mail, respectively to Calcutta, Madras, and Bombay, is likely to reconcile jarring interests in India; and, now that the Euphrates expedition is at an end, and the long line by the Cape is well nigh given up by its former supporters, at least as a medium of rapid conveyance, it would be most desirable to unite all the friends of steam communication at home, in one simultaneous effort. To have half a dozen different projects on the anvil at once, each with its little band of exclusive supporters, instead of one plan, with all these separate parties combined in its favour, is unhappily the ready way to frustrate the object of all, instead of advancing it.

In

There is one circumstance connected with the proposed line by the Red Sea which is so often misconceived, that it can never be too often adverted to. the appendix to Captain Grindlay's pamphlet a quotation is given from the letter of a Manchester manufacturer, in which the writer takes it for granted throughout that the aim of the promoters of the plan is to restore the commerce of the East to its ancient channel. It is no such thing. There are a thousand reasons why this would not be practicable if it were desirable, nor desirable if it were practicable. It is only proposed to make use of the shorter, or north-eastern passage, as it has been called, for the conveyance of despatches, letters, and passengers, so as to keep up a much quicker communication with the Eastern dependencies, than can be effected by the far superior mercantile line of the Cape of Good Hope. It is likely to be long enough ere the raw cotton of Hindostan, or the manufactured calicoes of Manchester, are transmitted or re-transmitted by way of the Isthmus of Suez; at any rate, no such thing is contemplated at present, and it is, therefore, quite a mistake for the Manufacturer" to argue "funupon the supposition that it is a damental feature" of the plan.