1858.] on some Improvements in Locks. 479 



which is done completely and with great simplicity by the moveable 

 stump of the " protector lock.*' 



The only inventions of this class which Mr. Denison thought 

 deserving of special notice, were a series of locks by Mr. Tucker, 

 of Fleet Street, of which specimens were exhibited, with a large 

 model of one of them, as of the other locks described in the lec- 

 ture. They have also the merit of being simple and cheap, and 

 unlikely to get out of order, and if not equal to Mr. Hobbs's in 

 security, they would baffle any but a very lirst-rate hand at lock- 

 picking, and are certainly superior to several more expensive locks 

 which profess to defeat the tentative mode of picking. 



The lecturer also described and exhibited a lock of an entirely 

 different construction, invented by himself. It is not intended for 

 furniture and small work, but for doors of safes, prisons, and other 

 places where a lock of great strength as well as security is required. 

 A description of it will be found in all the three books above-men- 

 tioned, and it is the only English lock to which the merit of 

 security against any known method of picking is ascribed by Mr. 

 Hobbs, in the Rudimentary Treatise on Locks. Its peculiarities 

 and advantages are, besides the important one already mentioned : 

 First, that a large and strong lock requires only a very small key. 

 (2.) It requires no key to lock it, but merely the turning of a 

 handle, the key being required for unlocking only. This obviates 

 the necessity for leaving your keys in the hands of other persons, 

 if you are only present when you want to open your door or safe, 

 and also removes the temptation to leave them in the lock, which 

 affords great facilities for having impressions taken from them. 

 (3.) The key-hole is so small that no instrument strong enough to 

 force the lock can be got in. (4.) The key-hole is kept closed by 

 a spring plate or curtain, which is pushed in by the key ; and when 

 the lock is open no instrument whatever can be got into the key-hole 

 to explore the lock. (5.) This curtain also keeps out dirt and 

 damp air, which frequently cause locks to get out of order, or at 

 any rate to want cleaning. (6.) There are no tumbler springs, 

 and so the tumblers can neither fail from the springs breaking, nor 

 can they stick together; both of which things not unfrequently 

 happen in tumbler locks with springs, and without separating 

 plates. (7.) The moving pieces in the lock are as few as possible, 

 being in fact none but the bolt, the tumblers, and the curtain. 

 (8.) Hence also the lock is easy to make, and cheap, and requires 

 no fine work to prevent friction of the parts, and make it move 

 easily. It is not patented ; the inventor being one of that increas- 

 ing number of persons who think that patents are an obstruction 

 to science, and waste more money than they gain for real inventors, 

 whatever they may do for patent-agents and patent-buyers. One 

 of the locks exhibited on this construction was made by Mr. 

 Chubb ; and Mr. Hobbs also applies them to safes, &c. when 

 ordered, though they are not yet made for sale. 



