536 TRANSACTIONS OF THE 



was made by first changing the form of the key, and in the act of 

 locking the tumblers were thrown on to the bolt, so that they 

 ceased to act as tumblers. 



Soon after another improvement was made which required two 

 sets of tumblers, and two keys to operate them, one of them 

 changeable, and from that improvements were made so that one 

 key only was used to operate the bolt and change the lock, and 

 from time to time new permutating locks have been introduced, 

 until there are now in use some eight or ten varieties, some of them 

 very ingenious and secure. 



No doubt there is still chance for improvement both in regard 

 to security and simplicity, and there is no doubt that open and 

 fair discussion upon the merits of locks, and the means used to 

 pick them, would be a public benefit, and produce a thorough 

 change in lock-making. 



It is said that the plan was suggested years ago that has since 

 been used, to open some of the best English locks, and the ad- 

 vantages of smoking or painting the tumblers to get impressions 

 has long been known, and yet by this operation one of our best 

 bank locks is now opened, proving that those who use the lock 

 should know the means the burglar employs, and then use their 

 judgment in selecting such as give the best security. I want to 

 bring to the notice of the Club the rotary lock, designed to be 

 used on stores and dwelling houses. It is free from the objections 

 found in locks now in use for that purpose, and has the following 

 advantages : 



1. A steel key that will not get clogged with dirt from the 

 pocket, and so small that it requires 60 to weigh a pound, and 

 will admit of the use of one even one-third less in weight. 



2. A large bolt that turns on a centre and grips on to the joint 

 of the door, and is so arranged that it is impossible to crush it back 

 with the burglar's jimmey. 



3. Its security against the operations of the lock-pick, being 

 impossible to open it with probes or picks, in the time tliat a burg- 

 lar would have access to the lock when on the door. And its 

 arrangement is such that no impression or copy of the inside work 

 of the lock can be taken at any time, whether locked or unlocked. 



