18 ANNUAL OF SCIENTIFIC DISCOVERY. 



Mr. Hodge stated, that the principle on which all modern locks are 

 constructed can be traced back nearly four thousand years. The three 

 best locks manufactured in England, during the last thirty years, are 

 those of Barron, Braniah and Chubb, and the principle of each is based 

 on the principle of the old Egyptian lock ; the difference between each 

 being only in the mechanical arrangement of parts to produce the same 

 effect. Locks, similar to those of Mr. Chubb, were formerly manufac- 

 tured by Mr. Andrews, of Perth Amboy, N. J. These locks Mr. 

 Newell succeeded in picking, and, in doing this, learned the means by 

 which he could pick his own lock, as it was made in 1841. Mr. Newell 

 also showed by this that his own lock, and all others based on the tum- 

 bler principle, were insecure against burglars. One of Mr. Newell's 

 locks, affixed to a safe, containing $500, the reward of the one opening 

 it, was picked in the Merchants' Exchange, N. Y., by an engineer 

 named Petis, and the money obtained. This led to the invention of 

 the parautoptic lock, which is undoubtedly the most perfect ever con- 

 structed. This lock, through movable wards in the key, is susceptible 

 of 419,000,000 changes. 



SAFE FOR THE KOH-I-NOOR DIAMOND. 



THE great Koh-i-noor diamond, during the London Exhibition, was 

 contained in a safe, curiously constructed by Mr. Chubb, for its protec- 

 tion. 



It consists, first, of an octagon table, G feet 6 inches in diameter, by 

 3 feet 4 inches high, the top and sides being made of half-inch wrought 

 iron plates, all secured together by being rebated and with angle iron. 

 In the interior is a fire-proof safe, 12 inches square, and 2 feet ( J inches 

 deep, the wrought plates being one inch thick. In the centre of the 

 safe is a platform, 9 inches square, on which the velvet cushion, jewels, 

 and setting are fixed. A hole is cut out of the table to allow the plat- 

 form to descend into the safe. In order to secure the diamonds at 

 night, a small door, 3 inches square, in one of the panels of the table, 

 is unlocked, and, by turning a winch, the platform gradually sinks into 

 the safe, and a sliding iron door is drawn over the opening at the top. 

 The cage is secured to the table by i pieces at the bottom ring, drop- 

 ping into corresponding holes, and these are locked by two separate 

 detective locks. The keys of these locks are held by the crown officers, 

 and without them, access to the jewels cannot be had. The key of the 

 small door allows the platform to be raised or lowered only, but does not 

 give access to the jewels. The weight of the whole is 30 cwt., and it 

 is bolted to the floor. 



ERICSSON'S PATENT CALORIC ENGINE. 



THIS is a scheme which Mr. Ericsson tried some years since, but 

 which, at the time, was not successful. Since then, his attention has 

 been directed to the removal of difficulties ; and in this he has so far 

 succeeded, that the engine has been patented, both in this country and 

 in England. A moment's reflection will show that there is a possibility 



