IMPROVED LOCK FOR HOUSE DOORS^ 20o> 



By an experiment with the lock fent herewith, it will be Advantages of 

 proved that two ounces added to the reliever, wiil ihoot the the improved 

 lock with more eafe than three pounds will do, applied to (he 

 bevel bolt ; and if the lock is rufty, the advantage will be 

 much more in favour of the new method. I natter myfelf it 

 will be of great utility to the public, as its conftruclion is fim- 

 ple and cheap. It may be added to any old lock, as may be 

 feen from that now fent. It may be advantageoully applied 

 to French windows and glafs doors, as it prevents the door 

 from being drained, or the glafs broke, by the force applied 

 to (hut them. I have fixed feveral locks, upon this new prin- 

 ciple, which anfwer well ; and if the invention meets with 

 the approbation of the Society, I hope to be rewarded ac- 

 cording to its merit. 



I remain, with refpect, , 



SIR, 

 Your mbft obedient Servant, 



WILLIAM BULLOCK. 

 No. 6, Portland Street, Soho, May 5, 1801, 



Plate X. Fig. 2. A. Is the new iron latch here affixed to Defcription , 

 an old common drawback houfe lock. 



B. An iron pin at one end of the latch, on which pin it is 

 moveable. 



C. A projecting part of the latch, which, when the com- 

 mon fpring bolt D of the lock is drawn back, in the ufual 

 manner, is forced into the nick on its higher part at E, by the 

 fpring F, underneath the latch. 



The bolt D then remains within the lock, until, on clofing 

 the door, the reliever G gently prefles on the lock box, fixed 

 in the common way on the door cheek ; which preflure draws 

 the projecting part C out of the nick E, and permits the end 

 of the bolt D, by the force of the fpring G, to Hide into the 

 lock box, and fatten the door. 



XIII. Ptfcripiion 



