which had the inconvenience of forming, as it were, a taking-up roller, round which the earth wound itself, until it formed a solid mass, in which the prongs entirely disappeared, is replaced by a number of discs revolving independently of each other; the prongs also being made so long that the earth cannot easily reach their roots. Another step was the addition of cleaning or doffing bars, for stripping the soil from the prongs. Of these, Roberts' machine affords an example. Its chief peculiarity, however, consists in the prongs being made to feather, somewhat like the floats of Morgan's paddle-wheel, the motion communicated to them resembling that of the fork in the hands of a man.

The labours of Hoskyns, the author of the Chronicles of a Clay Farm,' must not be forgotten. He has described graphically the "points" which are requisite to make a perfect steam cultivator, and consequently divested the subject, to the machinist, of one of its chief difficulties.

Besides a modification, proposed by Usher, of his steam-plough, in which he substitutes rotatory prongs for his points and mould-boards-involving, however, the difficulty, that he loses the aid to progression which the latter afford him-two other steam cultivators have been projected, both of which possess, in common with that suggested by Hoskyns, the distinctive feature that the rotation of the cultivating tools is not derived from the progress of the carriage. The first is that of Stephen Brown, who has two series of rotatory cutters, the second set working in intervals left by the first, and both driven through cross shafts from a small locomotive steam-engine forming part of the implement, and which may either work its way across the field by its own adhesion, or be drawn by horses. The second is the Canadian machine spoken of by Mr. Mechi in a recent letter to the 'Times.' It does not differ greatly from the preceding in its mode of operation, its novelty consisting in the arrangement of the parts, and in the adoption of a very light and compact form of engine.

The most recent rotatory cultivators that have been put practically to work are Bleasdale's and Mr. Samuelson's. The former somewhat resembles Parkes' subsoilers, but being calculated only to pulverize the surface soil, its weight is only about onehalf that of Parkes', and that weight (1 ton), instead of resting on two discs only, is distributed over seven. The chief novelty in it is the cleaning apparatus, consisting of an additional cylinder, suspended at an angle of about 45° above, and driven from the shaft of the primary or digging cylinder, and therefore revolving in the opposite direction to it. Its prongs act as a rotatory comb in stripping the earth from those of the former. This machine was exhibited at the Gloucester meeting of the Royal Agricultural Society, and on land previously broken by the plough acted admirably as a pulverizer and a weed extracter.

Whilst engaged in some experiments with a machine somewhat resembling that of Parkes', Mr. Samuelson's attention was directed to the steel digging-forks which have lately been substituted with so much advantage for the old trenching-fork, and it occurred to him that, by substituting light steel prongs for the wrought or cast metal ones hitherto used in rotatory implements, an efficient cultivating machine for horse power, strong yet comparatively light, could be made. In following out this idea, he has constructed his digging, or more properly, forking machine, not altogether unsuccessfully, as may be inferred from the number of them which are already in use, notwithstanding the recent date of its introduction.

The forks of the digging machine are made of the best cast steel that can be procured, of a square section, slightly tapered, bent on the angle and in pairs, at a cherry heat, and allowed to cool gradually. They are curved, so as to enter the ground easily, but to lift the soil as they come out.

The upper portion of six such pairs being laid between two half-discs of cast iron, grooved to receive them, the half-discs being afterwards united by bolts, form a digging wheel of which the discs represent the boss, and the points of the forks the spokes; the hoop or tyre is absent. A number of these digging wheels (seven in a full-sized machine) are hung on a bar, around which they rotate freely. Between each pair of wheels and on the same bar is hung a ring, which keeps them apart, and cleans the sides of the bosses. The frame containing the bar with the digging wheel also holds a number of cleaners, the ends of which scrape the soil from the circumference of the bosses and force it from the prongs. This frame, to which the shafts and draught links for the horses are also attached, is itself hung in front on another bar, connecting two segmental frames, one on each side of the digging frame. These contain the

wheels on which the implement rests when it is not in action, and which also serve to regulate the depth to which the forks of the digging frame are allowed to penetrate the ground. The segments at the back of the travelling wheel frames being toothed, two pinions gear into them, the place of which on the segments determines the height at which the digging frame is sustained; a winch attached to the latter works the pinions.

When the horses move forward, the attendant throws out of gear a pawl, which holds the pinions at any given point; the digging frame runs down by its own weight, the prongs enter the ground, and the depth of their penetration is increased or diminished by turning the winch in opposite directions, thereby causing more or less weight to rest on the travelling and digging wheels respectively. Meanwhile the resistance offered by the earth in front of the prongs causes the latter to revolve, and portions of the soil to be detached, which are thrown back, after having been lifted and broken by contact with the cleaning bars.

A full-sized machine weighs a ton, and breaks up (to a depth not exceeding 10 inches) a breadth of 3 feet at a time, equal to that of four ploughs, and equivalent to about five acres in seven hours.

The draught required varies, with the nature and state of the soil, from four to seven horses. A smaller implement is made for occupiers of land whose horse-power is limited, capable of working about three acres in the same time with three or four

horses.

About thirty digging machines, corresponding with the description here given, are at work in various parts of this country; one of them in this immediate neighbourhood, on the estate of Mr. Robert Harrison of Benningholme Hall.

Whilst speaking of the digging machine, it is right to state that it possesses, in common with all other rotatory implements hitherto made or proposed, this disadvantage, as compared with the plough, that it does not completely invert the soil. However, the occasions for such inversion are much more rare when we work with an instrument which leaves the ground broken, hollow and mixed, like the digging machine, than with one which, like the plough, cleaves off a slice and exposes its superficies only to the air; there being, in fact, this essential distinction between the two machines, that one allows the air and water to descend, whereas in the other, fresh soil must be brought up, if it is to be acted upon by the elements. Hence also an inconvenience is avoided by forking, which often accompanies the attempts to deepen the mould, by means of the plough, in plastic soils; namely, that the fresh soil so brought up forms a compact coating, and is consequently for several reasons injurious instead of beneficial to vegetation. Even were as many horses required for a given acreage with the digging machine as with the plough, there would still be a great gain both of horse and manual labour by the use of the former, since it effects at one operation the work of several ploughings and harrowings, or scufflings; but in fact it succeeded, during the dry weather in June, in preparing the ground for a crop on the strong clays in the vicinity of London, where a combination of the best implements previously in use could make no impression upon it.

The forks tend to pull out and leave the weeds on the surface, and it is therefore useful in eradicating the couch-grass, the vegetation of which, the action of the plough or scuffle, by cutting the tendrils, is calculated to promote.

Whilst these improvements have been in progress, the spirit of invention has not slumbered even at the antipodes; and we shall shortly see exhibited in this country an Australian forking machine, not differing very greatly from some of those which have been noticed. Mr. Wilson, the inventor, appears to have taken his hint from noticing in a track of a waggon-wheel on soft ground that the side of the tyre tends to abrade and throw back the earth. He prolongs the spokes of his wheels beyond the tyre in the form of spuds, which are segments of an epicycloidal curve, with a view to their encountering the least resistance in front or behind as they enter the ground.

Whatever may be the success of all or any of the cultivating machines which have been brought under notice, enough has certainly been done to demonstrate that we have entered upon a new epoch in the mechanics of tillage, and that how long soever the dominion of the plough may be destined to last, it is not henceforth to reign alone. Meanwhile the author was anxious to direct the attention of machinists to a brauch of their profession, than which none stands more in need of cultivation, and none will more amply repay it.

We are dealing with a department of industry, which, until lately, was oppressed with an excess of human labour, whilst the whole of its produce was liable to be depreciated far more than any other in value, by a comparatively trifling increase in its amount. But now the tables are turned; the supply of agricultural labour diminishes daily, whilst consumption is extending beyond all precedent, and the cultivator of the soil looks eagerly to the mechanic to cheapen his operations, and, jointly with the chemist, to aid him in making two blades grow where one only grew before.

On Railway Accidents by Collision, and Suggestions for their Prevention. By WILLIAM SCORESBY, D.D., F.R.S. L& E.

The absorption of previously existing modes of travelling, for the most part, by that of railway locomotion, has given to this method, in respect to its degree of risk of personal injury, a vast measure of public importance. Each one of us, indeed, is interested in the inquiry, of what may possibly be done to diminish these risks and damage?

It is not assured by me that railways are necessarily or practically more unsafe than former modes of conveyance; on the contrary, estimated proportionally, or di viding the number of miles travelled by the amount of injury sustained, we should have a result, I doubt not, still greatly in favour of railway travelling. For in esti→ mating the results of accidents, comparatively, we should remember that accidents by coaches, involving occasionally fatal cases, were extremely numerous, and that of these numerous accidents few became publicly known; but accidents by railways, no doubt sometimes very calamitous, are all recorded and generally become publicly known; whilst the enormous increase of travelling, ordinarily involving increase in the number of accidents and quantity of injury, gives an apparent aggravation of the comparative dangers. At the same time, accidents, it is notorious, are lamentably prevalent, and far more so, doubtless, than are due to essential and unavoidable risks. The prevalent sources of accidents may be considered as divisible into three characteristic classes:-1st, accidents from incaution or recklessness of passengers and workmen; 2nd, accidents from the giving way of machinery whilst the train is in rapid progress, or from the engine or any carriage getting off the line; and 3rd, accidents from the collision of trains or carriages.

It is to this latter source of accidents, yielding, I believe, in respect to passengers a considerable, if not a preponderating proportion of the injury referable to management, to which I have now to direct the attention of the Section. And to this particular source of accident, presenting in its results catastrophes of the most appalling character, a simple, and, as far as I am able to anticipate, effective remedy is capable of being applied. The plan I have to submit for this most desirable and important end comprises two leading points; the systematic employment of the electric telegraph, with a separate wire from station to station for management purposes only, and the securing and maintaining thereby a clear line from any one station to beyond the next before a second train should proceed,-a plan which, if fairly carried out, appears to be calculated, unless by the most wilful carelessness or desperate recklessness, to render collisions, if not impossible, certainly most rare.

It may be sufficient for explanation here to take a particular case of a railway, having considerable traffic,-suppose that of the down-line,—and in reference to a series of stations, which we may designate C, D, E, &c.

I. As to the Arrangements.

1. That there be an electric telegraph at each station, or intermediately, so as generally not to exceed a distance of three or four miles.

2. That there be a separate set of wires, to be used for station or traffic purposes only, worked by a supplementary battery, with a simple single-lever telegraph.

3. That the wires be disconnected at each station, so that station D should communicate with C above and E below only, with a warning bell, separately, at the termini, indicating at once whether the message is from above or below.

4. That a time-piece and register-book or journal be kept at each electric station, the book properly ruled for notifying the passing of each train clear of the stations above and below, respectively, in the column prepared for the several entries, i, e. the particular train, whether express, slow, goods, &c.

5. That the semaphore for the guidance of the engine-drivers of trains on each line of rails be worked from within the electric-office by the attendant there, showing -1. "A clear line to and beyond the next station." 2. "An encumbered line," for caution. 3. "Danger," for stopping the passing train as soon as possible. And to prevent interference, any ordinary signals for other management purposes might be made at a distance from the station above and below.

II. General Management.

To be peremptory on all officers and men, but with a discretionary power with the station-master only.

Suppose the case of management at station D, in respect to signals to and from C and E.

1. That in respect to management at station D, the departure of each train from D, as soon as it has gone quite clear of the station and is fairly on its way, be notified to C and to E, and reciprocally from C and E to D, the quality of the train being indicated, and the time being registered in the journal at each of the stations.

2. That no second train be allowed to start from C until notice has been received that station D is clear, so that at C it may be known that the whole line betwixt the stations and beyond the next station is clear, and collision, whilst no new obstacle is allowed, rendered impracticable.

3. That in the case of express trains passing C without stopping, warning of an encumbered line be given by the semaphore whenever a train is intermediate betwixt C and D, that the engine-driver may bring his train to hand-speed.

4. That no new obstacle be allowed at station D, or on the line near it (except in a side line), without previous notice to C, waiting a reply indicating “all right.” This will apply to shifting of carriages by shunting branch lines, crossing lines or junctions.

5. That, for security at junctions, crossing lines, &c., there be always an electric station at, or within commanding view and range of such junction; and that all trains and carriages arriving therein should come up at slow speed, and never enter on the main line till the signal of "clear line and station" be seen.

6. That the telegraphing station at junctions communicate with the next station thereon, as D with d, as well as with those above and below.

7. That no train pass any important junction but at slow speed.

8. And that response be made to each signal, to intimate that the announcement is observed and understood.

Several of these rules, it is well known, are already prevalently in use, but not as a general system. But under the arrangements on the system suggested, regulating the progress of trains so as to leave a clear line up to the next station and beyond it, and allowing no new obstacle without a previous signal to the backward station, and the response of "all right," it seems hardly possible, within the ordinary range of circumstances, for any collision to occur. And it will be obvious, that had such regulations been in force, some of the most calamitous results from this fearful source of accidents which have hitherto occurred could not have happened.

III. As to Discretionary Powers with the Station-master.

It being admitted that a stringent regulation after the manner of the plan suggested might retard the business operations on lines of great traffic, a discretionary power with the station-master, to be exercised on his personal responsibility, would be desirable, and might be necessary.

By means of the time-book or journal, however, he could always ascertain with tolerable accuracy the time he had certainly at command, and by enforcing the rule of a hand speed in the following trains, he might provide (except in tunnels where more special rigidness of rule might be called for) against the risk of running into a foregoing train.

The carrying out a plan of this kind would obviously involve expense; but it may be questioned whether the results in damage to carriages and costly engines, and awards of damages by juries, in regard to collisions, with the restraining of travelling by apprehension of personal danger, have not on the whole been as great or greater in expense and loss. But in any case the public might fairly pay for the additional security, for which a very trifling advance on the fares would be sufficient to compensate.

In regard to the importance of an additional or special electric telegraph and attendance, which constitute the basis of all the suggested arrangements, it may be observed that such addition is urgently called for on many lines of great communication, by reason of the almost perpetual employment, at certain times, of the common telegraph for its variety of purposes. This must necessarily embarrass the best of the existing arrangements, and cause recourse to the telegraph, either as to intelligibleness or promptness, often to fail in its intention.

In regard to the effect of the plan proposed on the speed of fast trains, it would probably do little more than regulate the distribution of the other trains more systematically. Yet the public safety is of such paramount importance as would be well worth some little sacrifice of time were it found necessary.

As to the probable effectiveness of a system of the nature of that now suggested, we may refer to a recent case of collision, which from the alarming risks involved in it, may emphatically serve us in the way of illustration. In the case of the recent collision at Hornsey, by the obstruction of the line by an accident in shunting, the proposed plan must have been an effective preventive; for before the shunting, notice must have been given to the station at King's-cross, so that if the express train had started, the shunting would have been delayed; or if the shunting had been sanctioned, the express must have been delayed (or gone on hand speed only) till a "clear line" had been announced. Such an accident, therefore, in this case would have been impossible.

In regard to the provisions of this plan for the guidance and protection of trains by the semaphore and other signals, may, in conclusion, merely refer to one for night-signals, being the employment (if it might be deemed of sufficient importance) of a wire, with explosive or illuminating combustibles attached to different parts of it, which could be ignited by the galvanic battery after the manner employed in blasting. The fearful calamity on the Great Southern and Western Irish Railway, which occurred on the 5th of October (within a month of the reading of the above communication), may still further illustrate the character and probable effectiveness of the plan here suggested for safety.-A passenger train was accidentally brought to a stand betwixt Sallins and Straffan stations. A cattle-train, unwarned, runs into it with a most appalling result. But, on the plan suggested, no such accident could have occurred. The cattle-train would not have been allowed to leave Sallins station till the line beyond Straffan was announced to be clear; or, if it were passing Sallins, without stopping, warned by the danger-signal there, it must have immediately brought up its speed and awaited the signal "clear line." Thus a catastrophe, involving the loss of fourteen or fifteen lives, with other serious personal injuries to the unfortunate travellers (besides the heavy loss and damage ensuing on the Railway Company), must, on the system suggested in this paper, have been prevented.

On the Consumption of Smoke in Furnaces and Manufacturing Premises. By the Rev. FRANCIS F. STATHAM, M.A.

Mr. Statham commenced by adverting to the fact, that all smoke consists of imperfectly consumed carbonaceous matter, and then proceeded to comment upon the various plans which have been suggested for its more complete consumption, which may be said to resolve themselves into one or other of the following systems :

1. The more careful feeding of the furnace or fire, so as to ensure a gradual and therefore more perfect consumption of the fuel employed.

2. A skilful admixture of atmospheric air with the incandescent mass, so as to effect a higher degree of heat, by which the smoke may be completely burned.

3. The application of steam or water in fine jets, which seems to operate in a twofold way, partly by chemical and partly by mechanical action.

And, lastly, by a process which it was the more immediate object of the paper to explain, viz. by a subdivision of the current of smoke into small columns, each of which may be dealt with more effectually than when united in one dense fuliginous

mass.

For the suggestion of the first method, viz. the more careful feeding of the furnaces, we are probably indebted to the illustrious Watt, who obtained a patent in 1785 "for a method of constructing furnaces in such a way as to cause the flame of the fresh fuel, in its way to the flues of the chimney, to pass, together with a current of fresh air, through, over, or among fuel which has already ceased to smoke, or which is con