the course of their hundred and eighteen miles of transit under the cloud of night? And what is the practice, in general, of the company, on this head? Are any of their other trains suitably provided with buffers? Or if not, what experiments or trials have they made, with a view to ascertain the best plan of so protecting them? All these are questions which ought to have been put at the inquest on the bodies of the persons killed, but were not; and it is the more necessary, therefore, that they should be put now, and distinct answers obtained. If we might give full credence to an assertion made by Mr. Saunders, that "every precaution that could be thought of to ensure punctuality and safety, has been adopted by the directors," there would be no need to push enquiry any farther; but we have just mentioned two very necessary and excellent "safety" plans which have been "thought of," but neither of which has, to a certainty, been "adopted;" and we doubt, exceedingly, whether it is in the power of the Great Western Directors to show that any better plan, or indeeed any plan whatever, has been "adopted" by them, having the same essential object in view -namely, the protection of passengers from destruction or injury in cases of collision. We believe that it is quite within the limits of mechanical practicability, to render all such collisions harmless; and we can never hold any company free from serious blame, which does not use its best exertions to do so.

As every grain of sand tends to check the advance of the ocean, so every movement of animal life tends to promote the circulation of the universe. Heat and

cold are, as every one knows, sensations; but they are sensations caused by different dispositions of matter, as we may see by their effects on substances which are devoid of sensation. The sensation of heat is caused by the motion of matter in the form of heat; and the sensation of cold, by the presence of more of the firmamental fluid, or "medium of space," than the vital energy can convert into heat with sufficient rapidity.

If animal life were extinct, the motion of the universe would cease, although the time for its entire cessation might be of long duration. Of course I mean mechanically-that is, without reference to the power of the Álmighty. Surely all sensations are the effects of the action of matter, or the recollection of the effects of such action. It is useless in this world to pretend to free ourselves from matter; matter must be the stepping-stone to another sphere, whatever other assistance we may require. The immaterial I presume not to discuss. A white leaf and a black dye might express all the wonders of creation. The firmamental fluid, or "medium of space," with an atom, can account for them. Under this view of things Alfonzo "the Wise" would never have said, "If he had been consulted in the creation, he would have made the universe more simply."

Dec, 22, 1841.

Your obedient Servant,
E. A. M.

THE TERM MEDIUM OF SPACE." SIR, SO many disputes arise from a want of agreement in the meaning of terms, that I am induced to make the following observations respecting the term, “Medium of space," in Mr. Pasley's last communication. Practician may be a better term than practitioner, and "Medium of space" may be a better term than "firmamental fluid," but in both cases, do not both terms imply the same things? Is not "the medium of space" "the freezing principle," so long inquired about by philosophers? Would it be possible for motion to occur within it, if it did not itself undergo a chemical change? And is there in nature any thing capable of producing this physical change, but the friction attendant on life?

STEAM NAVIGATION OF THE ATLANTICTHE RIVAL BRISTOL AND LIVERPOOL LINES.

[We copy the following historical retrospect from our excellent provincial contemporary, the Bristol Magazine. Although not free from the exaggeration of colouring common to all local effusions having for their object the exaltation of local achievements and interests, we consider it to be true in the main, and eminently deserving, on public grounds, of the attention of the public at large. To say how cordially we assent to all that is here. said, in praise of the Great Western and her performances, would be only to repeat what we have before more than once said on the subject; but we may be ex

cused, perhaps, for reminding our contemporary, who claims for Bristol exclusively the entire merit of all this vessel has accomplished, that her machinery, to which, more than any thing else, her pre-eminent success has been owing, were of London make, and, (at first, at least, if not to this day,) worked by London engineers.-ED. M. M.]

It will be fresh in the remembrance of many persons, that, previous to the starting of the Great Western on her first Trans-Atlantic trip, the idea of establishing steam communication regularly with the United States was held, very generally, to be a pure chimera; and a high scientific authority was understood to have stated in his lectures, that it never could be accomplished. During the time the Great Western was on the stocks, however, other parties, seeing the grand scale on which the attempt was to be made in Bristol, resolved to endeavour to eclipse it, by enlarging on the same plan in London. Thus the British and American Steam Navigation Company was formed; and, in order to deprive Bristol of the honour of being first in the field, they chartered one of the largest and most powerful steamers then in the world-the Sirius, of 700 tons, and 320horse-power-a proportion, be it observed, which by ordinary calculation ought to have given her greater speed than the Great Western. This vessel was ostensibly put on to pre-occupy the ground for the British Queen, which was then building, and being sent round to Cork at the latter end of March, 1837, under the command of Lieut. Roberts, R.N., who was subsequently lost in the President, she sailed thence for New York on the 4th of April, with a fine N.E. wind, and three days afterwards the Great Western started from Bristol for the same port, with a gale of wind "in her teeth," and with 240 miles further to run than the Sirius. Under these circumstances, it was not within the bounds of probability, in the absence of accident to either, that the Great Western could overtake the Sirius, and accordingly the latter did reach New York first, having arrived on the evening of the 22nd of April at New York, after a passage of eighteen days from Cork, and early the following morning the Great Western was reported, having arrived from Bristol in fifteen and a half days. Thus establishing her superiority so triumphantly, that the interest of the enterprize was speedily transferred to her; and it was evident to all, that no kind of comparison could be made between the suitableness of the two vessels for traversing the Atlantic. The voyage of the Sirius proved little or nothing; the distance between Ireland and New York had often been run by sailing vessels in less time than eighteen days, though perhaps scarcely

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ever on the outward passage. But, outward or homeward, no one ever heard of the distance between Bristol and New York being accomplished in fifteen days; and it was the Great Western one, therefore, which even then established the entire success of the attempt.

Several competitors, entered the field, and two other steam-boats besides the Sirius started about the time of the Great Western, and managed to get across the Atlantic; but these either never repeated the attempt, or they gradually dropped off, while the Great Western still pursued "the even tenor

of her way." Public attention, however, was in some measure diverted from the Great Western by the gigantic preparations of the British and American Steam Navigation Company, who appeared determined that her glories should be speedily eclipsed, or lost in the splendour of their own achievements. What Bristol had accomplished with such apparent facility, must be still more easy to London and Liverpool; and shortly afterwards the British Queen, and then the Great Liverpool, and the President, successively entered the lists, and disputed with her the supremacy of the Atlantic Ocean. In the mean time the attention of the government was attracted to the importance of establishing a mail communication by steam with the British Possessions in America; and it is understood that the Great Western Steam Ship Company offered for the contract, on terms very favourable to the Post Office Establishment. Whether it arose from the difficulty of impressing the government with the idea that any thing excellent, in the way of enterprise, could originate in Bristol or not, we cannot say, but without, we believe, any intermediate communication with the proprietary of the Great Western, some additional conditions were tagged to the proposals, which probably if they had been made aware of them, they would cheerfully have complied with, and the contract for the transmission of the British Mails, by way of Halifax and Boston, was given to a Liverpool house-who were to build vessels we know not how much superior to the Great Western-at an expense to the country of fifteen thousand a-year more than the Great Western Company required, and which bas since been increased to thirtyfive thousand a-year.

While these vessels are in preparation the competition on the Atlantic takes place, and the proprietors of the proud steam-ships, who scarcely thought it a compliment to hear them spoken of as rivals of the Great Western, were not long in discovering that to build a steam-vessel that should successfully contend with her for the palm of excellence, was not quite so easy as they had imagined.

The government contractors proceeded to carry out the terms of their agreement, and four large steamers, on the most approved models, were constructed for the purpose, with less bulk and greater power than the Great Western, from which it was expected that an increase of velocity and more punctuality would be secured; and against these vessels, which run to Halifax and Boston, with eighty thousand a-year of the public money to back them, the Great Western has had to compete singlehanded for the last two seasons.

We do not wish to institute any invidious comparisons; but something is due to justice, and there are a few statistical facts connected with this subject which might form the ground of a curious enquiry. In the first place, the Great Western proprietary might reasonably have expected, without the slightest approach to anything like presumption, that our own government would feel some interest in the success of an undertaking which appeared to have attracted the sympathies of the whole civilized world. When it was understood that the Great Western had finally departed for America the press of Europe was occupied with the subject, and as the time approached for her return, nations stood on tip-toe awaiting the event. We need not dwell on the enthusiasm which seemed to pervade society at large on her successful return: it was like a national congratulation,-the winning of another battle of Waterloo, without its horrors. Again and again the experiment was repeated, and always with the same success; and when in the wide world she had not a competitor, and the Government saw the expediency of dispatching our North American mails by steam, what was more to be expected than that it would rejoice to throw in its powerful aid in support of an undertaking which had already earned "golden opinions from all sorts of people?" On the contrary, however, not only the Great Western Company obtained no preference, but they were not even allowed to carry the mails at less than any other Company could undertake them; and instead of receiving encouragement from the Government, a premium of 15,000l. a year was absolutely given for the building of vessels to oppose them, and as this, it appears, was not enough, a sop of 20,000l. a year has since been added to keep up the spirit of the thing.

We are well aware that the wisdom of Government is easily arraigned by taking a onesided view only of a question; and it will naturally be inferred that its objects were such as could not be carried out by the Great Western proprietary, and that Liverpool was the most suitable port for the station of the vessels. We come, then, to inquire what the

exigencies of the Post-Office service particularly demand,-evidently speed and punctzaality; and, as far as these are concerned, it will not be difficult to show that, so far from gaining by making Liverpool the American mail station, it is a positive disadvantage to the country, and that in respect to the speed of transmission, the Government pays its thirty-five thousand a year extra for less than nothing.

We have not space, nor is it indeed necessary, to go into a regular analysis of the voyages of the Great Western, and the Liverpool and Halifax line of steamers. It is well known, that for speed the former has never, on any occasion, been surpassed on the Atlantic; while for punctuality, no kiud of comparison can be made between the Great Western and any of her competitors. What, for instance, is more common than to see in the London papers such paragraphs as the following:-"No account of the Caledonia yet, now three days over-due," "Some anxiety is felt respecting the Colombia, which ought to have arrived on Tuesday last," "We are still unable to give our readers any account of the arrival of the Arcadia." And we are sure the vigilant gentlemen connected with the London press in this city will bear us out in saying that nothing is more uncommon than their being kept waiting at Pill six hours for the arrival of the Great Western. And as to the general question of the relative merits of the Great Wester, and Bristol, versus Liverpool and the Halifax steamers, the last voyage will afford a very good criterion for estimating the whole.

The Britannia left Liverpool for Halifax and Boston on the 21st of October; and the Great Western, two days afterwards, left Bristol for New York, having to pass Halifax and Boston; from the latter of which there is railway communication with New York, notwithstanding which she delivered her letters in New York nine hours before the arrival of the mail per Britannia.

On the return voyage, the Britannia got home in fourteen days, (exclusive of delay at Halifax,) to Liverpool; and the Great Western, with a day's steaming farther to run, in thirteen and a quarter, to Bristol, the latter delivering her news in London within thirty hours of the time of passing Cape Clear; a period in which, without fear of falling into the error of Dr. Lardner, we may safely assert it never was, nor ever can be done by way of Liverpool. Nothing, therefore, can be more certain than that at the present time the New York letters, posted per the Great Western, are delivered in Liverpool sooner, via Bristol, than they could be by their own mails direct, if sailing at the same time; and it is equally easy of demonstration, that even

if the Great Western had no advantage over them in point of speed, the same end would be secured in a general way, were the Gloucester and Bristol railway completed.

The distance between the Bristol and the Liverpool courses, in favour of the former, calculated to a point of junction off Cape Clear, we will only estimate at forty miles, though we find that, when it is a question of the distance run, they call it seventy in Liver. pool; and we will allow this forty to be run, on an average, in four hours. Now we know it for a fact, from the best authority, that there is occasionally only nine feet, at low water, in the Victoria Chaunel, at Liverpool, and that a steam-vessel, drawing twelve and a half feet, may be detained five hours outside. All the Halifax line have been detained-the Britannia was detained three and a half hours her very first voyage-and allowing, on an average, that this disadvantage will make the difference six hours in favour of Bristol, it is not too much to say, that when the Gloucester and Bristol railway is opened, we shall be enabled to deliver the American letters in Liverpool, via Bristol, sooner than they could get them by sea direct.

PRACTICE

MATICS

AND

PRACTICIANS, V. MATHE

AND MATHEMATICIANS.-S. Y. IN REPLY TO MR. CHEVERTON.

Sir,-If what somebody said of me "many, very many years ago," had been as unimportant to Mr. Cheverton as it is irrelevant to the present discussion, he would not have quoted it. It is with my remarks he has to contend; what somebody said I should be, or what I am, it is impertinent on his part to observe upon. But if Mr. C. wrote the paper from which he quotes, (for I have entirely forgotten both it and the occasion of it,) he may console himself by imagining that, whatever I may be, I might have been something worse, if the censure he has treasured in his memory for the aforesaid "very many years" had not "alighted" on my devoted head.

If Mr. Cheverton's paper, in No. 956, had explained and enforced the necessity of caution in the application of mathematical theories to practical purposes, I should not have found fault with it; but its tendency appears to me to be widely different, and also to be utterly pernicious; and I read it with feelings of great indignation. I am old enough to remember the time when practical men regarded theorists with a feeling nearly allied to contempt and dislike; I have seen this feeling gradually give place to a better one, arising from more enlightened views; and I have seen with delight the benefits de

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rived by both classes-but more particularly my own-from the greater intimacy and better understanding which has grown up between them. While this is progressing, in a manner which must gratify all lovers of knowledge, up starts Mr. Cheverton, and does his best to persuade the less educated class that it is the superior of the two; that the science which is more general in its application, and more extensively useful than any other, is a noxious science; that it produces something worse than "baneful effects;" that it is a science" feeble" in means, but "arrogant of pretension," &c. &c.; and I did his paper the undeserved honour of getting angry with it.

I did not expect that my remarks, which appeared in No. 958, would be particularly pleasing to Mr. Cheverton; but he was not considered when they were written. I attacked his statements and his arguments; and, by way of defence, he, in No. 959, attacked me and my manner; neither, it seems, is to his taste, which is a misfortune about which your readers will probably not feel any great concern, and which I have not leisure to deplore. As to whether I have shown an inclination to "distort and misrepresent' Mr. Cheverton's statements, your readers can judge for themselves, if they choose to take the trouble.

These forests are understood to have originally extended, with little exception, from the sea-coast to the confines of the extensive prairies of the western states; but the effects of cultivation can now be traced as far as the foot of the Alleghany Mountains, the greater part of the land between them and the ocean having been cleared and brought into cultivation. It is much to be regretted that the early settlers, in clearing this country, were not directed by a systematic plan of operations, so as to have left some relics of the natural produce of the soil, which would have sheltered the fields and enlivened the face of the country, while at the same time they might, by cultivation, have been made to serve the more important object of promoting the growth of timber. Large tracts of country, however, which were formerly thickly covered with the finest timber, are now almost without a single shrub, every thing having fallen before the woodman's axe; and in this indiscriminate massacre there can be no doubt that many millions of noble trees have been left to rot, or, what is scarcely to be less regretted, have been consumed as fire-wood. This work of general destruction is still going forward in the western states, in which cultivation is gradually extending; and the formation of some laws regulating the clearing of land, and enforcing an obligation on every settler to save a quantity of timber, which might perhaps be made to bear a certain proportion to every acre of land which is cleared, is a subject which I should conceive to be not unworthy of the attention of the American Government, and one which is intimately connected with the future prosperity of the country. But should population and cultivation continue to increase in the same ratio, and the clearing of land be conducted in the same indiscriminate manner as hitherto, another hundred years may see the United States a treeless country. The same remarks apply, in some measure, to our own provinces of Upper and Lower Canada, in many parts of which the clearing of the land has shorn the country of its foliage, and nothing now remains but blackened and weatherbeaten trunks.

The progress of population and agriculture, however, has not as yet been able entirely to change the natural appearance of the country. Many large forests and much valuable timber still remain both in Canada and in the United States; the Alleghany Mountains, as well as other large tracts of country towards the north and west, which are yet uninhabited, being still covered with dense and unexplored forests.

The timber trade of the United States and of Canada, from the quantity of wood which

is required for home consumption and exportation, is a source of employment and emolument to a great mass of the popula tion. It is carried on to a greater or less extent on all American rivers, but the Mississippi and the St. Lawrence are more especially famous for it. The chief raftsmen, under whose direction the timber expeditions on these rivers are conducted, are generally persons of great intelligence, and often of considerable wealth. Sometimes these men, for the purpose of obtaining wood, purchase a piece of land, which they sell after it has been cleared; but more generally they purchase only the timber from the proprietors of the land on which it grows. The chief raftsman and his detachment of workmen repair to the forest about the month of November, and are occupied during the whole of the winter months in felling trees, dressing them into logs, and dragging them with teams of oxen on the hardened snow, with which the country is then covered, to the nearest stream. They live during this period in temporary wooden huts. About the middle of May, when the ice leaves the rivers, the logs of timber that have been prepared and hauled down during winter are lanched into the stream, and being formed into rafts, are floated to their destination. The rafts are furnished with masts and sails, and are steered by means of long oars, which project in front, as well as behind them: wooden houses are built on them for the accommodation of the crews and their families. I have several times, in the course of the trips which I made on the St. Lawrence, counted upwards of thirty men working the steering oars of the large rafts on that river, from which some idea may be formed of the number of their inhabitants. Those rafts are brought down the American rivers from distances varying from one hundred to twelve hundred miles, and six months are often occupied in making the passage. When it is at all possible, they moor them during the night in the still water at the edge of the river; but when this cannot be done, they continue their perilous voyage in the dark, exhibiting lights at each corner of the raft to warn vessels of their approach to them. The St. Lawrence rafts vary from 40,000 to 300,000 square feet, or from about one to no less than seven acres in surface, and some of them contain as much as 50007. worth of timber. If not managed with great skill, these unwieldy specimens of naval architecture are apt to go to pieces in descending the rapids, and it not unfrequently happens that the labour of one, and sometimes two seasons is in this way lost in a moment. An old and experienced raftsman, with whom I had some conversa