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have led him partly astray. He appears to have imagined, that the waste is to be met with, not by running into an old coal pit entirely filled with water, but one that has been filled up with earth, &c., or containing only a small Should these not quantity of water. have been his ideas, I have erred on the side of good feeling. Should he have supposed as I have observed, then the use of his syphon may be so far allowed, but not otherwise; as in the event of the pit being filled, or nearly so, with water, then the necessity of the syphon must be obvious: in that case, where is the use of its application? what, in the name of wonder, is it then to do? must he empty the pit by the mouth? In doing this, he would certainly devise ends to meet the wishes of the querist; he might thus throw the waste water through a good corn or pasture field, in place of conveying it on a subterranean journey through the dark bowels of the earth. But this is in no respect agreeable to the nature of the query. It is plain, that the water is to be conveyed to the engine pumps of the new workings. This, of course, cannot be done but by a subterranean passage. This passage may be longer or shorter, according to pleasure; but always allowing a certain thickness between the new workings and the waste, according to the supposed weight of water that is contained in the waste. Should this passage be only the entrance to a spring or springs of water, rather than a collected body of water, then a passage of any width might suffice, as not more water would issue from it perhaps than the engine could draw; or, if otherwise, the course might be easily made to answer according as circumstances would show. Should there be a large body of water, perhaps to secure safety it might be necessray that a very small outlet therefrom be made, and the nearer this enters the bottom of the pit the better. Should the workings alone be filled with water, then the water will be about the level of the seam of coal working; then, unless a bore be made through the coal seam, or beneath it, the water could not satisfactorily be carried off but by the application of a syphon.

G. M.'s ideas in regard to the use of the syphon, appear to be, that there was only a small quantity of water in the waste, not many feet; the passage was then to be carried to near the surface of

the water, and the syphon from thence placed therein; but G. M. can best tell, perhaps, how the syphon could properly and conveniently be got there, and what advantage it would be, put in contrast with running a passage immediately to the bottom of the pit, and striking at the whole of the evil at once, and that in such a manner, as that neither danger nor farther trouble, than merely running it off, could be experienced from the water.

That such is the most efficacious mode of doing away with the evils arising from wastes, is the humble opinion of, Yours, &c.

6th June, 1825.

L. M.

GENTLEMEN,-I see in No. LXXV. G. M. wishes to make it appear, that he has the theory, if not the practice, of coal mining.

I must inform him that I made no such conclusion as, "that, to act according to his plan, the waste must be exactly ascertained." Where this is mentioned, it is with reference to the plan I proposed.

But we will set his syphon to work. He says, his bore or funnel may begin any where, provided it end about the surface of the water contained in the waste. Now, we will suppose that the distance of the old pit in the waste, from the engine pit, is 100 fathoms, which is no great distance; and that the water in the waste is running out at the mouth of the old pit, which will be the case if the fountain head is above the level of it; and also, we will suppose that it is 30 fathoms deep. Now, G. M.'s syphon, in this case, must be placed upon the surface; the one leg entering the old, and the other the new, pit, a distance of 100 fathoms, which will only drain the waste 34 feet. Now, after this, a funnel must be cut 100 fathoms, and his syphon applied again to drain it 34 feet more; and so on, until you reach the bottom of the pit. So I think we will let his syphon run.

Other cases more favourable to G. M. might be stated, but without any probability of his plans being adopted.

I had nearly forgot his "Gutter," but what would G. M. think of one 30 fathoms deep and 100 long?

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Superficial knowledge.-It is asserted that this is the age of superficial knowledge; and amongst the proofs of this assertion we find Encyclopedias and other popular abstracts of knowledge particularly insisted on. But in this notion, and in its alleged proofs there is equal error.

Where

ever there is much diffusion of knowledge there must be a good deal of superficiality; prodigious extension implies a due proportion of weak intensign; a sea-like expansion of knowledge will cover large shallows as well as large depths. But in that quarter in which it is superficially cultivated, the intellect of this age is properly opposed, in any just comparison, to an intellect without any culture at all: leaving the deep soils out of the comparison, the shallow ones of the present day would in any preceding one have been barren wastes. Of this our modern Encyclopedias are the best proof. For whom are they designed, and by whom used? By those who in a former age would have gone to the fountain head? No; but by those who in any age preceding the present would have drunk at no waters at all. Encyclopedias are the growth of the last hundred years; not because those who were formerly students of higher learning have descended, but because those who were below Encyclopedias have ascended. The greatness of the ascent is marked by the style in which the more recent of the Encyclopedias are executed : at first they were mere abstracts of existing books-well or ill executed at present they contain many original articles of great merit. As in the periodical literature of the age, so in the Encyclopedias it has become a matter of ambition with the publishers to retain the most eminent writers in each several department. And hence it is that our Encyclopedias now display one characteristic of this age, the very opposite of superficiality, (and which on other grounds we are well assured of,) viz. its tendency, in science, no less than in other applications of industry, to extreme subdivision. In all the employments which

are dependent in any degree upon the political economy of nations, this tendency is too obvious to have been overlooked. Accordingly, it has long been noticed for congratulation in manufactures, and the useful arts, and for regret in the learned professions.

The Camera Obscura.-In a letter from Sir Henry Wotton to Lord Bacon is the following curious relation respecting Kepler, the celebrated astronomer and mathematician; to whom Sir Henry, then being ambassador to one of the princes of Germany, had made a visit.

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I laid a night at Lintz, the metropolis of the higher Austria, but then in very low estate, having been newly taken by the Duke of Bavaria, who, blandiente fortuna, was gone on to the late effects: there I found Kepler, a man famous in the sciences, as your lordship knows, to whom I purpose to convey from hence one of your books, that he may see we have some of our own that can honour our king, as well as he hath done with his carmonica. In this man's study I was much taken with the draught of a landscape on a piece of paper, methought masterly done; whereof inquiring the author, he betrayed by a smile it was himself, adding that he had done it non tanquam pictor, sed tanquam mathematicus. This set me on fire; at last he told me how. He had a little back tent, (of what stuff is not much importing,) which he can suddenly set up where he will in a field, and it is convertible, like a wind-mill, to all quarters at pleasure: capable of not much more than one man, as I conceive, and perhaps at no great ease; exactly close and dark, save at one hole, about an inch and a half in the diameter, to which he applies a long perspective trunk, with a convex glass fitted to the said hole; and the concave taken out at the other end, which extendeth to about the middle of this erected tent; through which the visible radiations of all without are intromitted, fall

ing upon a paper which is accommodated to receive them; and so he traceth them with his pen in their natural appearance, turning his little tent round by degrees till he hath designed the whole aspect of the field. This I have described to your lordship, because I think there might be good use made of it for chorography; for otherwise to make landscapes by it were illiberal; though surely no painter can do them so precisely."

Luminousness of the Sea.-The sparkling and luminousness of the sea at night is sometimes a very beautiful phenomenon. The finest display of the kind I ever beheld took place in the 3d degree south latitude. One dark and rather hazy night about eight o'clock, the sea within ten yards of both sides of the vessel suddenly became studded with a vast profusion of dazzling stars, which varied in colour and magnitude, and continued to vanish and disappear and appear again, as if they had been alternately extinguished and rekindled. Some emitted a gloomy white light, and others exhibited shades of blue and faint red. We were going about eight knots, and the reflection from the ship's wake was so strong that the poop and after cabin were completely illuminated. The train which extended from the rudder was indescribably magnificent, being about half a mile in length, and exhibiting a vast assemblage of fiery orbs, co-mingling, uniting, dispersing, flashing, breaking into fragments, and changing colour, without intermission. While all this was going forward, I observed that large portions of the neighbouring sea were at intervals suddenly covered with a glow of blueish light, which increased in intensity for a few moments, and then vanished away. These vivid patches could be distinguished nearly as far as the horizon; but they occurred most frequently in the vicinity of the starry train above described. The whole spectacle continued in its glory about half an

hour, after which the luminousness diminished by degrees, and at length disappeared altogether.-Howison's Foreign Scenes.

The Properties of Aquavita.-The following are among the properties which, according to old Holinshed, whisky possesses, when properly used and moderately taken. -It drieth up the breaking out of hands, and killeth the flesche worms, if you wash your hands therewith. It scowreth all scurfe and scalds from the head, being therewith daily washt before meales. Being moderately taken, it sloweth age; it strengtheneth youth; it helpeth digestion; it cutteth flegme; it abandoneth melancholie; it cherisheth the heart; it lighteneth the mind; it quickeneth the spirits; it cureth the hydropsie; it healeth the stranguarie; it pounceth the stone; it expelleth the gravelle; it puffeth awaie all ventositie. keepeth and preserveth the head from whirling; the eies from dazeling; the toang from lisping; the mouth from muffling; the teeth from chattering; and the throte from rattling. It keepeth the weasun from stifling; the stomach from wambling; and the heart from swelling; the belie from whitching; the guts from rumbling; the hands from shivering; and the sinews from shrinking; the veins from crumpling; the bones from akeing; and the marrow from soaking.

It

The Barber's Pole.-Many mistakes have been made on the origin of a barber's pole, which is vulgarly supposed to be indicative of the poll or head of his customers this is a far-fetched, although a popular conceit; that various-coloured staff being no more than a sign that its master could breathe a vein as well as mow a beard, and professed bleeding as well as shaving the custom then being, which is yet observed in some villages, for the practitioner to put a staff into the hands of his patient while the latter was undergoing the operation of phlebotomy.

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NOTICES TO CORRESPONDENTS.

Our Correspondents must be deferred to next week; none of them, however, are forgotten.

Communications from intelligent Mechanics will be very acceptable, in whatever style they may be written, if they contain a full account of the invention or im provement, which is the subject of their notice.

Published every Saturday, by W. R. M'PHUN, 155, Trongate, Glasgow, to whom Communications (post paid) must be addressed.

CURLL, PRINTER.

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COLUMBIAN PRINTING PRESS.

THIS printing press, which, so far as we can judge, is superior to any which has yet been brought into use, was invented by Mr. George Clymer, formerly of Philadelphia, now of London. After introducing it into pretty general use throughout the United States, the inventor came to Britain, for the purpose of bringing it into notice in Europe. The plate requires certainly little or no explanation, as it is sufficiently plain. It will be seen that in this press the power is obtained by a combination of levers, instead of by the screw; and the power thus obtained is, it seems, much greater than that of any other printing press. The difference between the large Columbian and that of the most improved and largest press now in use, has not, we believe, been as yet precisely ascertained; but it is said that a much better impression can be produced by it from double demy or double royal forms, with a pull much lighter than is agreeable to the pressman, than can be produced from any other press by applying both hands to the bar handle, and exerting the utmost stretch of manual strength. This power, however, is susceptible of gradation to the smallest as well as to the largest forms, and in the

hands of a good workman, it is equally well adapted to all kinds of work to a single octavo page, or the smallest card, or the heaviest double royal sheets. Indeed, such is its power, that it has been found sufficiently easy for a boy of fifteen to pull down. Besides want of power in the ordinary printing presses, another most obvious defect is an imperfect adjustment of the platten and bed for the types, causing an inequality of impression which frequently baffles the skill of the pressman to remedy. In the Columbian press, the surface of the iron platten and iron bed for the types being perfectly level, an equal impression on every part of the sheet is insured. Another of its advantages seems to be, that by its. use considerably less injury is done to the types than by the other presses in use. From its great power, a sharp impression can be brought off without indenting or sinking the types into the paper, whereby much less injury will be done to the types; because the deeper the impression is, the more severely the paper operates on the extremities of the sharp angles of the types, and, consequently, they receive the quicker and more destructive injury.

ON GRAFTING FRUIT TREES.

EXPERIMENTAL cultivators have varied the methods of grafting in various ways; but those of practical use are whip grafting, cleft grafting, crown grafting, root grafting, and inauhing. For common grafting trees, which are set in gardens that are kept for private use, the standard or stock may be from three to four feet high, and to begin and complete the operation,

the following implements are necessary: 1st. A neat small hand saw. 2d. A grafting or strong knife with thick back. 3d. A grafting chisel and small mallet. 4th. A budding or sharp pen knife. The following materials must also be provided. 1st. Strings of hemp or woollen yarn, to tie the graft and stock together. 2d. A composition of good binding clay, horse and cow dung,

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