450 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



6,500 bushels. The whole of the paper of Major Taylor was entertaining, 



and showed that he had really given much time to a subject which, for 



importance, has no equal in this country. 



The subject of "Locks" was selected for the next evening's discussion. 



On motion, adjourned. 



JiREH Bull, Secretary pro tern. 



American Institute Polytechnic Association, | 

 January 16, 1863. ) 

 The Chairman, S. D. Tillman, Esq., presiding. 



There being no preliminary business, the regular subject of the evening 

 was taken up. 



Locks. 



Mr. Bull.— Mr. Chairman, I proposed this subject of locks with a view of 

 getting some information on the subject from a gentleman of the very highest 

 eminence in this department. I have the honor of introducing to the meet- 

 ing Mr. Hobbs. 



The Chairman. — Mr. Hobbs will have the floor. 



Mr. Hobbs. — I came here, Mr. Chairman, with the expectation of partici- 

 pating in a discussion on the subject of locks, and not with a view of de- 

 livering a discourse on it. 



Mr. Bull. — I hope Mr. Hobbs will favor us with some remarks on the sub- 

 ject. 



Mr. Hobbs. — Without models or drawings, Mr. Chairman, it will be impos- 

 sible to explain the details of construction; I will, therefore, confine myself to 

 the general principles of security against picking. All locks may be divided 

 into two classes. The first class is that of locks with wards, in which fixed 

 obstructions are secured in tlie box or about the key-hole, to prevent the 

 key from turning unless openings are cut out from the bit to correspond 

 with the wards. These locks have been made in great variety, and the 

 wards have been fashioned in very ingenious forms to make it difficult to 

 fit keys to them. But the difficulties are easily overcome by introducing a 

 blank key with a coating of wax and turning it against the wards, which 

 impress their positions and forms upon the wax, A skeleton key is then 

 made, not to fit all of the wards, but simply with the bit constructed to pass 

 them, by which means the lock can be opened. This class of locks has 

 been abandoned where great securit}^ is required. 



In the other class of locks the obstructions to the motion of the bolt are 

 movable. These movable obstructions are usually called tumblers, but why 

 they should receive this name I do not know; they certainly do not tumble. 

 But whether tumblers, latches, pins, slides or wheels, these locks belong 

 properly all to the same class, though they have been made in endless 

 variety. In the most simple the tumblers or latches must be raised high 

 enough, and no harm is done if they are raised higher; but a more difficult 

 lock to pick is that in which, if the tumblers are raised too high, their hold 



