In all effective locks there exist obstructions, stationary or moveable, whose object is to prevent the lock being opened by any key, except that made for the purpose. In the case of a " ward M lock the obstructions are stationary, and consist of parts of concentric walls, inside the lock, arranged around the keyhole as centre. The key has its front edge, that is the edge or end at right angles to the stem, cut into a series of notches, through which the otherwise obstructing walls can pass. In such a key the edge of the operating part furthest from the key tube is the portion that actually unlocks the lock, i.e., causes the bolt to move. This being the case it is obvious that such a type key could have all the notches merged into one large notch, and still be able to open the lock. It is also clear that a piece of steel wire, say half round section, can be so bent, that it will pass into the lock, avoid all the obstructions, and make contact with the bolt only, and move it, in other words " pick " the lock. Ward type keys are mostly made with a hollow centre, i.e., tube at the key proper end, and this slides over a projecting pin fixed on the internal plate of the lock. This pin is made to act as a centreing device to keep the key in the centre of the lock, and also as a safeguard, as unless the key will slide over it, then it cannot enter the lock. From this it follows that the hole down the key centre must be kept clear from any filling matter whatever. From the above it is fairly clear that a " ward " type lock is not really very secure, as a key can readily be made to operate it, or it can be " picked " with a piece of steel wire, etc. It is easy to unlock this type of lock with a suitably bent wire to anyone who can visualise the shape of the lock interior by simply feeling it with a wire, but if he cannot do this, and many cannot, then it is no use wasting time fumbling about, and stirring up the lock's interior with a wire, as this will be trusting to pure chance whether the lock opens or not. Should the lock refuse to open with the correct key, note whether the key goes right home into the lock, if it does not, then it probably is due to some dirt, etc., either inside the key or lock; remove it. If the key goes right in or home, but will not turn appreciably, there must be either some foreign matter in the lock, or the lock is in some way damaged internally, or else the key is distorted, bent, or damaged; inspection should show which it is, and the remedy will be obvious. If the key goes in well, and turns nearly right round, but fails to shoot the bolt, and will not move forward, do not force it, but with the free hand thump the box, etc., to jar the lock, at the same time turning the key quickly, but slightly, to and fro. The key will probably suddenly engage the bolt and unfasten the lock. If it does not, then try again but press the key bodily to first one side, then the other, then upwards, etc., etc., as this may enable it to engage the bolt. Patience is required, force is useless, and can only make matters worse. When the lock is unfastened, it will be better to take it right off, and open it. If the trouble was that the key would just not open the lock, examine the lock interior, and note carefully whether the spring is broken which should engage with the bolt, or whether the trouble has been due to wear either in the lock, or on the key. Speaking generally, " ward " locks are useful to prevent honest but inquisitive persons, or children, or dishonest but totally unskilled persons from interfering with the contents of any locked receptacle, but are quite useless against a burglar or thief with say five minutes to spare, even if he were obliged to open it without noise or damage; they are, however, less expensive than lever locks, and appear impressive, hence their sales. The key of a " lever " lock can be separated at once from " ward " lock keys, by its being cut into what may be likened to a series of fingers, side by side, projecting at right angles to the key stem. If the key of either a ward or lever lock be lost, and it is possible to take the lock off, and open it, then it is perfectly simple to file a key blank to suit the lock. It is, however, quite a different matter to pick a " lever" lock, especially if nothing be known either of the shape of its key or the arrangement internally of the par-| ticular lock. The " fingers " on a lever key are for the express purpose of moving a certain part of the lock forward in order to release the bolt, and if the " fingers " be not right, then the bolt cannot be moved. As it is not possible to tell whether the key used is moving the particular parts insufficiently or too much, or to tell which part is at fault, it is clear that picking a lever lock calls for great patience, coolness and time. Of course the general result is that force is used, and the locked article broken open.