I have now taken up the more common repairs, and will close by hastily speaking of the more rare cases, and the adjustment of the hair spring, etc., etc. It is often the case that there is never end shake to the balance to make it absolutely safe when screwed into the case, and when this happens I take the point of a sharp graver and prick up a burr on the bridge, and never on the plate, as any unskilled workman does, for the under side of the bridge never being finished, you really mar nothing, and sometimes this raising of the cock (or bridge) becomes a necessity, to have it clear the rim of the balance, which, if raised, it will clear, and then by bending down the end of the cock at point where the jewel is, and thus regulate the end shake. I hardly know how to give directions how to proceed in adjusting hairsprings, when they are disarranged, but if I could see you, I could explain by example what I cannot well do in words. To commence, a hairspring, when there is no power applied to balance from the jewel pin, should be, when pinned, just as free from any twist or cramping as it would be if lying flat and free on a smooth piece of glass, before it has been pinned at either end, and when it is pinned in the watch (at stud and collet) it should be thus free. To bring it thus requires demonstration that cannot be made on paper, unless you could make diagrams, too numerous for this article. What I have said regarding it, however, gives an idea of how a hairspring should be pinned. Common sense is demanded here as elsewhere. To put a watch in beat, too, is a very important item, which I do by placing sharp pointed tweezers, first on one side of the arm of balance and then on the other, and so pin my hairspring in the stud, that it will let off as readily on one side as the other. I had forgotten to say that every watch should have a little oil on the face of the pallet stones. I know full well that some workmen will say that there should be none, but I can tell of scores of watches that have failed and indeed stopped simply for want of oil on the pallets. Selecting mainsprings, too, needs much more care than is usually given to this department, and as a rule even the watch factories fill the barrel too full, that is, too long springs. Whether I am correct in this or not, you cannot be too particular in selecting the right strength, length, and width of mainsprings. Mainsprings should be well and carefully oiled. There are many ways of replacing broken teeth in wheels, and the width of the web and the size of the teeth has much to do with how they are put in, but I usually dovetail them in, and then with the very tiniest bit of soft solder fasten them, but in so doing be positive you have got off all soldering fluid, that it will not rust the pinion into which it meshes, and be very particular to have it exactly like the rest of the teeth in same wheel, and don't mar the web of the wheel more than is possible.