ent impulses from an electromagnet.
The first known clock of this kind was invented by Wheatstone and exhibited by him in 1840.
Appold, Bain, Shepherd, and others have contrived clocks on the same principle.
See electro-magnetic clock.
E-lec′tes of powder.
It was first tried in blowing up the sunken hull of the Royal George, in 1839, by Colonel Pasley.
In 1840 the plan was used in Boston Harbor by Captain Paris.
In 1843, by Cubitt, for overthrowing a large section of Round-downires, requiring the deflection of two of the needles to indicate each letter.
His first dial instrument was patented in 1840; modifications were, however, subsequently made in it. The transmission of messages was effected by a wheel having fifteen in the manner generally practiced until a comparatively recent period.
An envelope-machine was invented as far back as 1840, but De la Rue's, 1845, appears to have been the first which achieved any notoriety.
Envelope-machines, so called, gene