and timber of small dimensions cut into comparatively short lengths. According to Gayer (op. cit., p. 264), a load consists of from 55 to 70 cubic ft. of light coniferous wood, and a sledder working on a sledding track, having a moderate and equable gradient, can convey from about Fig. 289.

108 to 180 cubic ft. of wood per diem to a distance of 1 miles (3 kilomètres), or from 350 to 425 cubic ft. for the half of that distance; but either deficiency or excess of slope prevents such good results being obtainable.

The larger sledges, to be dragged by horses or oxen, are altogether of heavier construction, for large timber transport. They consist of a front

sledge and a hind sled, in order to keep the ends of the logs from trailing along the ground and cutting up the earthwork. In some parts of the Black Forest large single sledges are often loaded with from 1,050 to 1,100 cubic ft. of Spruce or Silver Fir wood cut up into fuel billet lengths.

Sledding and sledging operations take place for the most part only while the ground is covered with snow, so that it is a method that can only be applicable to localities having severer winters than are usual throughout the greater part of Britain. Such operations can, however, easily be arranged for during the summer months through special preparation of the tracks (Fig. 289), by means of laying round poles on the ground, or split poles with the smooth side uppermost, so as to minimise the friction. These have to be fenced in with flange-like side-poles, in order to keep the sleds or sledges from gliding off the track. They are, in fact, just like rude railway tracks in appearance, but the sleepers are smooth and round on the top so as to offer a minimum of friction, whilst the sleds run over these horizontal bars in place of along the outer line of parallel poles. These sleeper-pieces must not be farther apart than will admit of the sled or sledge always resting on two, i.e., will prevent any portion of the sledge touching the ground. According to Gayer (ibid.), in the construction of such summer-sledging tracks, with Silver Fir and Beech, at Hochwald, near Barr, the preparation of the track cost 43s. for every 337 yards over a total distance of ramifications amounting to 12 miles; and the sledding track lasted ten years. Where dragging from the interior of the wood to the nearest roadway has to take place by means of horsepower, it may be calculated that one horse will be required for every 7 to 9 cwt. of dead weight of the timber; but, of course, much depends on the nature of the soil at the time of dragging.

Timber-Slides.-There are few branches of utilisation of forest produce which offers so wide a field for improvement as this particular method of extraction,—and more especially if the timber-slides can be made to terminate at any river or good waterway, that can be utilised as a floating channel for the conveyance of the timber to any favourable mart, or to large sawyards, whence transport of the converted material is favourable by road, rail, river, or sea. This is a method of transport widely and cheaply practised throughout all the mountainous tracts of Central Europe.

1. Wooden Timber-Slides.-There are different forms of timber-slides; but the leading principle is, of course, that a good bed should be prepared, down which the timber can glide with a minimum of friction, whilst sidepieces protect the logs or fuel billets from springing out of the slide. Wooden timber-slides are constructed of 6 or 8 poles of from 4 in. to 1 ft. in diameter; the lowest two of these form the base of the sliding-trough, which usually varies in total breadth from about 2 to 5 ft. The slides which are intended for the conveyance of large logs of timber, must of course be constructed more solidly than those required only for fuel billets. That represented in Fig. 290 is a long timber-slide in the Triftenthal Forest in North Tyrol.

The gradient is a very important matter with regard to the construction of timber-slides; for, whilst too slight an inclination makes them practically useless, too high a gradient is apt, to induce such a velocity in the shooting timber as to cause it to spring out of the trough. But the permissible or advantageous gradients vary between wide limits, according to the circumstances of each case.

Thus, when dry slides are to be operated on, a gradient of 20 to 35, or even up to 40 per cent. is not excessive for fuel billets and small wood; whilst for heavy logs of long timber a range of from 15 to 20 per cent. is

ample. But when a snow or ice slide is to be operated upon during winter, the most favourable gradients are from 6 to 12 per cent. for small wood and fuel billets, and from 3 to 6 per cent. for large timber. And where, as would very often be the case in the damp climate of the Highlands of Scotland, operations would be conducted during wet weather as a rule, a gradient about half way between these two extremes for summer and winter slides should best suit the object in view. Wherever in any given parts of

the slide a high gradient is unavoidable, it should be succeeded by a short horizontal stretch, or by a slight rise, in order to check any tendency to the acquisition of excessive velocity by the timber. A check may also be given to the velocity by means of a drag, as represented in Fig. 291. This consists of two poles, between which the logs have to pass on their downward passage; and the friction thereby arising tends to lessen the velocity that has been acquired by the timber. Another method is to form checks by

interrupting the slide here and there, and slightly changing its course at places where the log springs from one section of the slide into the other. Slides for the transport of long logs should always run horizontally for a considerable distance before terminating, as even then the stems are often shot out to a distance of 80 or 90 yards over gently sloping ground on issuing from the slide.

2. Roadway or Earthwork Timber-Slides are a means of transport very highly to be recommended for long logs of timber, when the horizontal projection of the pathways and side-roads has taken place in long sweeping curves, round which long coniferous logs can easily glide. They can be formed practically in the same manner as has already been sketched with regard to the formation of summer sledging-tracks, and as is exhibited in Fig. 289. The most advantageous gradient is from 9 to 15 per cent., the steeper inclination being at the top portion or commencement of the slide, and the slighter gradient towards its termination.

The leading principle is to have broad, sweeping curves, and to avoid sudden turns and changes in general direction as much as possible. Often, however, the latter are necessary, and they are then arranged for in the manner indicated in Fig. 292. Here the stem coming down in the direction ab bumps against the bundle of faggots fixed as a buffer, rolls over into the lower track diverging at a very acute angle, and continues its way slowly in the direction of mn. Concerning this method of transport Gayer (op. cit., p. 278) makes the following remarks:

"In lofty, hilly, and mountainous tracts, timber transport by means of roadway timber-slides deserves far more attention than has hitherto been given to it. It occasions no loss of timber; and it is thoroughly economical, as from 100 to 300 logs daily can be shot down a slide over 14 miles in length, whilst the roadways can also be utilised for sledging. It is a method of transport offering particular advantages in localities where draggingpower is available only to a limited extent."

Where the gradient of such roadway-slides is merely between 8 and 12 per cent., transport operations can only be conducted during winter whilst snow is on the ground; but when it amounts to from 10 to 18 per cent., the work can be undertaken during the summer months. The logs should be launched butt-end foremost into the slide, after the points have been adzed or rounded with the axe, in order to ensure their gliding smoothly over the sleepers placed at short intervals across the track. As may be noted from Fig. 292.

the illustration, wherever the logs are not likely to run out of the track on the upper side, no flange-pole is requisite except on the lower side; but, otherwise, guiding-poles have to be fixed along both sides of the slide or shoot.

Fig. 293.

Operations of this description require to be conducted with something like military precision and good organisation in order to prevent accidents. Before timber is launched at the upper end, a bugle or horn signal is given, which is repeated down the line by men stationed at different points, and then passed up again, to ensure that the slide is clear, before the log leaves the top. Its arrival at the depôt below is indicated by another preconcerted signal being passed up the line; and so on with each log.

A Californian Flume.

When all the timber from the fall has been transported, the logs used in the fencing-in of the slide can also be shot down, commencing at the top, if the slide be no longer required.

Flumes. In California, throughout the Rocky Mountain tracts, enormous quantities of timber are conveyed for immense distances in flumes worked by water-power. The construction of the flume is exhibited in Fig. 293. It consists of a water-tight trough formed of side-boards mm, and is worked by means of diverting the flow of any rivulet or water-channel into the trough, so as to carry down the timber placed or launched therein. They are, in fact, nothing more than water-troughs or floating-channels on a small scale. They seem, however, to be such a very economical and prac