a guard rail of the common form, to guide the wheels on the track, and prevent their striking against the edge of the safety rail.

The construction of the improved switch, which has been described, is fitted for only two permanent tracks; but the switch may be adapted to any required number of tracks, by increasing the number of rails on the switch, and providing a safety rail and spring for each additional set of rails, in the manner before described.

The switch is moved and regulated by the lever and rod applied to the common switch.

In the use of the improved switch the safety rail is placed against either of the main, or diverging tracks of the railroad, and at least two of the permanent rails are covered. As the cars proceed in the direction from the hinge to the head of the switch, they will be directed on the track covered by the safety rail, and will be prevented from running off from the rails; when they move in the opposite direction, they must be carried upon the permanent rails, because the end of each of those rails is covered and continued by the switch rails. Although the switch may not have been moved, the flanch of the car wheel, if running on the outer rail, will move the safety rail so far as to admit of the free passage of the cars, and after the train shall have passed the spring will restore the safety rail to its place.

The accidents which have occurred in the old mode of constructing, cannot occur in the improved mode of building switches, which has been specified; for the safety rail, adjusting itself, will always furnish a continuous line, and prevent the cars from running off from the track. Another great advantage of the safety rail is, that the cars on many diverging tracks, will be carried upon one line of rails without the care and labour of adjusting the switch for each. What the said Eaton claims, and desires to secure by letters patent, is the mode of constructing switches with a movable rail, operating by a spring, or weight, or otherwise adjusted, in the manner before described, so as to cover two, or more, permanent railroad tracks.

NATHANIEL EATON.

Specification of a Patent for a Means of Producing Adhesion between the wheels of Locomotive Engines and the rails of railway tracks. Granted to JORDAN L. MOTT, of the city of New York. To all whom it may concern: Be it known that I, Jordan L. Mott, of the city of New York, in the state of New York, have invented a new and useful method, or apparatus, for the purpose of producing adhesion between the wheels of locomotive steam engines and the rails of railway tracks, by which device such engines will be enabled to overcome the resistance arising from ascending grades without its being necessary to throw any additional weight upon the wheels for that purpose, and I do hereby declare that the following is a full and exact description thereof.

My improvement consists in the combined application of moisture and of sand to the wheels, by means of which the sand may be dis

tributed over the surface of the tire, or tread of the wheels, and will be made to adhere with sufficient force, and in sufficient quantity, to produce the required adhesion. In the accompanying drawings, fig. 1, is a perspective representation of a locomotive steam engine and carriage, having two driving, and four truck wheels, to the former of which my apparatus is applied; its application, however, is not limited to locomotives of any particular construction, but is equally adapted to those with four, six, or eight driving wheels; fig. 2 is an end view, and fig. 3 a side view, of such part of a locomotive as is requisite to show the manner of applying my apparatus. A, is the steam

Fig. 2

Α

a

chamber, and B, the body of the boiler, which may be constructed in any of the ordinary forms; c, c, are hoppers, or boxes, for containing sand, the lower portions, s, of which boxes are to be charged with this material in a dry state. These hoppers may be varied in situation, but I, in general, place them directly over the centres of the driving wheels; the sand is to be discharged from them through a tube, or opening, at their lower ends, which opening is governed by a valve, or sliding shutter, by which it can be properly regulated; a, represents the handle of such a valve, or sliding shutter, which may be constructed and managed in any of the known ways of constructing and managing devices of this kind; D, D, are steam, or water pipes, which are to convey the moisture to the wheel from the steam chamber, boiler, or other source. These pipes are to be governed by a stop cock, as shown at c, c, and they discharge the water, or steam, on to the periphery of the wheel, and moisten it directly in advance of the aperture for the discharge of sand; if steam is used, it will be condensed upon the wheel, but it will probably be found to economize heat by using water. The quantity expended in either case will not, however, be important in amount. Instead of using the water, or steam, from the boiler, water may be conducted through the pipes from a cistern, or reservoir, of cold water, placed in any convenient situation for

MOTT'S PATENT.

that purpose. Although I prefer to discharge the sand and moisture upon the wheels, it will be manifest that they may be directed with like effect on to the rails in advance of the driving wheels, and that the combined operation of the moisture and sand will be the same, but the apparatus will, in this case, have to be extended, without producing a corresponding advantage.

Having thus fully described the nature of my invention, and shown how the same may be carried into operation, what I claim as new, and desire to secure by letters patent, is the applying of sand to the peripheries of the driving wheels of locomotive engines, in combination with the application of water, or steam, to moisten the wheels, for the purpose of causing the sand to adhere thereto, substantially in the manner set forth, and so as to enable such locomotives to ascend inclined planes, or elevations, on a railroad, in consequence of the friction produced by such application; I claim also the applying of moisture and sand simultaneously to the tops of the rails in advance of the driving wheels, considering this mode of applying the moisture and sand as a mere modification of the general principle upon which the utility of my invention is dependent.

JORDAN L. MOTT.

Practical & Theoretical Mechanics & Chemistry.

Memoir on the Preservation of Timber. By M. A. BOUCHERIE, M. D. [CONTINUED FROM PAGE 286.]

Is the Penetration always complete?

In the white woods we find a central tube of variable diameter, which resists impregnation; in the hard wood, it is the most central part of the heart which remains in its natural state. This fact is worthy of attention, and appears to me, fruitful in results, both in regard to practical applications, and to physiology.

In the white woods, this central part is known to those who work in wood, as presenting the least resistance, and being the most easily decayed. It does not become impregnated, because it has no longer a circulation, or life; it is dead wood, placed in the midst of wood perfectly alive.

Many observations confirm this view of the subject, which may lead us to learn more accurately the qualities of wood. Thus I have found that this non-impregnation appears elsewhere than at the centres of the stems. It is found disseminated in all possible forms, and to a variable extent, in different parts of the same stem. Alongside of a band, the fibres of which are perfectly impregnated, will be found another band, whose fibres are not affected, and this occurrence is very often repeated in the same stem. What is the cause of this? A little attention will suffice actually to show it to us in the greater number of cases, and to deduce it by reasoning when it is not evident.

These accidents are always due to some obstacle in the circulation, and almost always, at the base of the bundles not impregnated, we

will find a knot, or a decay. No movement can then be produced during the life of these parts of the stem, and it is not astonishing that we.cannot succeed in impregnating them after the tree is cut. It is, I repeat, dead wood, which must be destroyed more rapidly than the wood around it, since it has been for a long time subject to the influences which destroy all organic substances. I am aware of the boldness of such an opinion, but I also see how curious will be the experiments made to confirm, or destroy, it. I call attention to it.

This irregularity of the penetration gives rise to very remarkable peculiarities; I have pieces of wood which owe to it the appearance of marble.*

As to the non-penetration of the most central parts of the heart of oak, elm, &c., I consider it also as a proof that the circulatory movement has for a long time ceased there; it is again, dead matter, placed in the midst of wood full of life. A number of persons will contradict this proposition, for the heart of oak is generally considered as the part of the wood which presents the greatest resistance.

In order to answer this objection, I will make one remark, and quote a single fact.

The fact, I owe to M. Emery, ingenieur en chef des ponts et chaussès, he informs me that in a structure of oak wood, he observed that all the pieces, in other respects sound, or nearly so, upon their exterior, were completely worm-eaten in their central parts, and that this alteration always occurred in oak wood under the same circum

stances.

The remark is as follows; in the ordinary distinction which we draw between the sap wood and heart of oak, we ground it upon the difference of colour, which is presented by a section perpendicular to the axis. All that is white, or nearly so, is sap wood; all that is dark, is heart wood. Admitting the distinction, and drawing it in the same way, there is no doubt but that the sap wood is far more alterable than the heart; but the difference is not the same when we ground it upon the fact of penetration, and consider as sap wood all that is impregnated, and as heart, all which resists. The sap wood then approaches much nearer to the centre, and constitutes three-fourths of the mass of the wood. And it may well be the penetrable substance alone, in which the circulatory movement existed, which presents this resistance to alteration; it is probably for want of careful observations that it has been admitted that the central part of the heart possesses properties which do not exist in the intermediate and living parts which are interposed between the heart and the sap wood. In

• This central portion, this heart of white woods, varies according to age, in regard to the volume of the tree which it occupies. In trees of great age, it is larger in proportion, than in those more young. I experimented upon a pine tree eighty-five years old, in which it represented one-fifth of the cube of the wood.

All hard woods do not resemble each other, in regard to the volume of impenetrable heart wood, as compared with the parts which it is possible to impregnate. Thus, in sea-side oaks, experiment has proved that we may succeed in penetrating three-fourths of the mass. I have found other oaks, growing on the same soil, of which not more than one-ten h could be impregnated. The season in which they were cut, it is true, was not the same, but I have not yet been able to determine whether the season was the only cause of the differences.