A burnt bone is an excellent substitute for the crust, and has the advantage of causing the brush to impart a very brilliant appearance to objects on which it is used.

Cleaning with a brush is less used now than formerly, as it can be adopted with safety with the old-fashioned gilding, but is too severe for the thin galvanic coats that are applied at the present day. It may, however, be resorted to for getting up the surface of polished brass wheels, for example. Put some French chalk or powdered hartshorn (which can be bought at a chemist's) in pure alcohol. Shake the mixture, and with a fine paint-brush coat the object with a small quantity of it, subsequently brushing the surface with a brush that is in very good condition. Polished wheels may be made to present a very brilliant appearance by this means, but their teeth and the leaves of pinions must be afterwards carefully cleaned. The French chalk and hartshorn are more effective according as they have remained a longer time in the alcohol; doubtless owing to the fact that the hard grains are then more completely dissolved.

In soaping, it is advisable to use a soap that quickly produces a good lather. The object is held in the hand and cleaned by rubbing with a soft brush charged with this lather; then immerse first in clean water, and subsequently in alcohol, moving it about in each: it may be left for a few seconds in this latter, and, on being removed, is dried with a fine linen rag or soft muslin. A stroke with a soft brush in good condition will give brilliancy to the surface. If cold water dissolves the soap very slowly, employ warm. If about to soap polished wheels, the surface must be first got up with a buffstick and rouge, or by brushing with hartshorn. The balance spring may be cleaned by laying it on a linen rag doubled, and tapping it gently with a brush charged with lather; then dipping in water and alcohol in succession. The alcohol may be used hot or cold, its action being more rapid and effective in the former case. But there is no occasion to use hot alcohol except when dealing with substances such as wax, that resist its action.

The employment of essences in cleaning watches is becoming more general every day. They are to be obtained at all the tool-shops, together with full instructions in regard to their use. A few observations may be not out of place. The objects are left in the solution for a few minutes, in order to allow all adhering matter to dissolve, but not too long, as certain qualities of benzine, etc., are apt to leave stains. Dry the pieces on removing them, and finish by passing over a fine brush that has been charged with chalk and subsequently rubbed on a hard crust or burnt bone. The following composition hat . been strongly recommended: - 90 parts by weight of refined petroleum, and 25 of sulphuric ether. The objects are immersed for several minutes, and on removal from the bath are found to be clean and bright. It must not be forgotten that many of these essences are liable to ignite near a lamp.

The following 3 rules must be observed in arranging a system of putting the watch together: (1) avoid taking up the same piece 2 or more times; (2) bold it lightly, as any pressure will produce a mark; (3) keep it as short a time as possible in the fingers. Any linen rags used must be free from fluff, but rags , of all kinds should as far as possible be replaced by certain kinds of tissue paper. The best kind will be that which, while securing a given degree of pliability, will prevent heat and moisture from passing through. Blue tissue paper should be avoided, as it is often found to encourage the formation of rust On steel-work.

The following order is often adopted in putting together the ordinary form of Geneva watch. Commence by putting the several parts of the barrel together, attaching it to the bar and observing the directions given farther on with regard to the distribution of oil. Owing to the position of the stop-finger, it is sometimes found that the mainspring must be set up either 1/4 or 3/4 of a turn. Very often 1/4 is not sufficient, and in such cases it is necessary, before putting together, to ascertain that the spring admits of at least 5 or 5 1/4 turns m the barrel. If it will not allow this amount, and yet has to be set up 3/4 of a turn, too great a strain will come upon the eye of the spring in winding. Fix the chariot with its endstone on the under side of the plate. Replace the fourth wheel, making sure that it is free, has no more than the requisite end-shake, and is upright. Then the escape wheel, testing it in a similar manner. See that the teeth have sufficient freedom on both sides of the cock passage, then make the 2 wheels run together with a pair of tweezers or pegwood in all positions of the plate to make sure of everything being free.

Having attached the index and end-stone to the balance cock, and the balance spring to the balance (observing that the centre of the stud is against the dot on the balance rim), place some oil in both the balance pivot-holes; adjust the balance to the cock, after placing a drop of oil in the cylinder, and set in position on the plate. Some workmen apply a drop of oil to the top of the escape-wheel pivot-hole before setting the balance cock in its place, but others prefer only to add the oil after the escapement has been tested. Placing a small piece of paper first between the balance and cock, and then between the balance and plate, ascertain whether the escape wheel occupies its correct position in reference to the cylinder, in order that the escapement may act properly. This test is especially necessary in dealing with very thin watches or those in which the cylinder banking slot is exceptionally narrow.

Next fix the barrel bar to the plate. Set the third wheel in its place, and lastly the centre wheel, after putting a little oil on the shoulder of its bottom pivot. Before putting the bar over it, apply oil to the top pivot in a similar manner; then screw it down. After this is done, screw on the third-wheel cock. Apply a small quantity of oil to the 2 centre pivots, and very lightly to the others that have not already been oiled; give a turn to the key, and listen to the tick of the watch in all positions. This should always be done before replacing it in the case. After passing the slightly-oiled set-hands arbor through the centre pinion, and adapting the cannon pinion to its end, reverse the watch, passing the end of the centre arbor through a hole in the riveting stake, so that the watch is supported on the end of the cannon pinion; a light blow of the hammer on the square end of this arbor will then suffice to drive the cannon pinion home. Some do this before replacing the movement in its case, and some after.

Add a little oil to such pivots as have not already received enough, and fix in their places the remaining parts of the motion work, the dial and hands: the watch then only requires to be timed.

The distribution and application of the oil are of more importance than might be thought, and have a very marked influence on both the time of going and the rate. Very fluid oil may be used for the escapement and fine pivots, where only a small quantity is needed and the pressure is slight; but it is not suitable in other places, on account of its tendency to spread, and leave the rubbing surfaces. If too much oil is applied, the effect is the same as if there had been too little; it runs away, and only a minute quantity is left where it is wanted.

To apply oil to the coils of the spring is not enough; some must also be placed on the bottom of the barrel. Before putting on the cover, moisten the shoulder of the arbor-nut that comes in contact with it with oil: by doing so, when oil is applied to the pivot, after the cover is in its place, this oil will be retained at the centre of the boss in the cover. Moreover, it will not then be drawn away by the finger-piece, passing from this to the star wheel. The oil applied to the upper surface of the ratchet, to reduce its friction against the cap, must not be in such quantity as to spread on to the winding square. It is a good plan to round off the lower corner of this cover. The observation made in reference to the oil applied to the barrel cover may be repeated for the centre wheel.

After the drop of oil is introduced into the oil-cup of the balance pivot-hole, insert a very fine pegwood point, so as to cause the descent of the oil; a small additional quantity may then be applied. When this precaution is not taken, it frequently happens that, in inserting the balance pivot, its conical shoulder draws away some of the oil, and there is a deficiency both in the hole and on the endstone. Some workmen place a single drop of oil within the cylinder, and when the escape wheel advances each tooth takes some up. This method is unsatisfactory, because the earlier teeth receive such a quantity of oil that it runs down the pillars, where it is useless, and merely tends to increase the weight of the wheel. A much better plan is to put a very small quantity in the cylinder and on the flat of each tooth, or every second or third tooth. It will thus be evenly distributed, and will not tend to flow away. The escape-wheel pivots require but a small quantity of oil. It often happens, however, that the workman applies too much, and it runs down to the pinion.

The leaves thus become greasy and stick, while the pivots are running dry.