2lJd Frnceedi?2gs of the 



darker-coloured portions. The roots were secured in a delicate 

 little cane basket, and have not as yet been examined with re- 

 spect to their powers or composition. 



Friday, February 9 th. 



Mr. Ainger delivered a Discourse, the subject of which was, 

 *' The Principle of Security in the various kinds of Locks :" the 

 following is an outline of this communication : — 



The means of giving security to locks are of two sorts. The first 

 consists in numerous obstacles (commonly called wards) ^to the 

 passage of the key, which requires, therefore, a peculiar form to 

 evade them. 



The second consists in a number of impediments to the motion 

 of the bolt ; those impediments being so contrived that their abso- 

 lute and relative positions must be changed before the bolt can be 

 withdrawn. 



Means of the first class are defective, because a surreptitious in- 

 strument need not thread the mazes of the obstacles or wards ; it 

 escapes them by taking a path on the outside of them, which is 

 unavoidably left for the passage of the extremity of the key. Com- 

 plexity in the form of the wards, therefore, does not increase se- 

 curity, neither does it add to the difficulty of imitating the key, 

 because in all keys of this sort nearly two-thirds of the metal is 

 superfluous, and requires not to be copied. 



Means of the second sort are the most ancient, having been 

 known in Egypt above four thousand years, as was inferred by M. 

 Denon, from some sculptures on the great temple at Karnac, repre- 

 senting locks similar to those now used in that country, in which 

 means of this sort are employed. The bolt, and a fixed part of the 

 lock are each pierced with any number of holes, arranged in any 

 chosen form, those in the bolt and in the fixed part coinciding when 

 the bolt is locked. These holes are occupied by pins which are 

 contained in the fixed part and descend into the bolt, so as to pre- 

 vent its motion till they are removed wholly into the fixed part. 

 This is effected by a key having the same number and arrangement 

 of pins, and of such a length that they elevate the ends of the pins 

 in the lock to the plane of motion between the bolt and the fixed 

 part. This key is introduced laterally through a long tube, at the 

 end of which it acts vertically upon the pins, whose position, there- 

 fore, it is difficult to ascertain. 



This principle of security was not generally known in this country 

 or in Europe, till it was re-invented by Mr. Barron, and applied by 



