526 TRANSACTIONS OF THE 



Mr. Marshall applied tliese ideas to a padlock, for which inven- 

 tion the Society of Arts voted hira a reward of ten guineas. In 

 1784 the society gave a silver medal to Taylor, of Petworth, for 

 improvements on the latch or spring bolts of common locks. 



Bramah's improved lock was registered in 1784. 



Bullock's drawback lock, for house doors, came next. 



Stansbury, of America, made a lock of great merit. A flat 

 circular plate turned on the centre pin by the key, which also 

 commands certain steel pins to arrest the plate. 



Nicholson's Iock had more than 6,000 combinations. It re- 

 quires no key. It contains four wheels, by which the combina- 

 tions may be increased nearly 60,000 times. 



Somerford was rewarded for his improved lock, by the Society 

 of Arts. 



Extracts by H. Meigs. 



ELECTRICITY— TELEGRAPHIC COMMUNICATION. 



In 1747 a committee of the Royal Society of London conducted 

 a series of experiments on the transmission of electricity consid- 

 erable distances. They began by placing a wire across West- 

 minster bridge, and found a return circuit through the water of 

 the river. This was found on the 14th and 18th of July, 1747. 

 One end of the wire was held in contact with the coating of a 

 charged jar, and by a person who held it in one hand, and with 

 the other put an iron rod into the river's edge. On the opposite 

 side of the river a gentleman held a wire which was capable of 

 being put in contact with the bridge wire, and at the same time, 

 with the other hand, could dip an iron rod into the river. The 

 shock was very sensible to all in contact with the wire, and some 

 alcohol was inflamed by the electricity after it had passed through 

 the water ! 



The next experiment was at the New river at Stoke Newington, 

 on the 24th of July, 1847, at two places, at one of which the dis- 

 tance by land was 800 feet, and by water 2,000 feet. The other, 

 distance by land 2,800 feet, and by water 8,000 feet. In this 

 experiment the shock felt by the operators was as strong when 

 the rod was placed on the land, twenty feet from the river, as 

 when placed in the river. This occasioned a doubt whether the 



