MECHANICAL COMPOSITION IN PRINTING—TURPAIN. 127 
the wheel is very rapid, lasting scarcely one-fifteenth of a second, 
the band then remains stationary for nine-fifteenths of a second, the 
whole turn thus taking ten-fifteenths, or two-thirds of a second. 
While the band is motionless, seven letters, Z (fig. 13), press against 
the paper, and those that find perforations make contacts closing 
electric circuits. This is accomplished by the heel of the lever Z, 
which raises the piston X, pressing the spring B against C and 
making the contact. 
The electrotypograph is controlled by electricity, hence its name, 
but its inventors used only very simple electrical arrangements, with 
weak electro-magnets requiring a current of low tension. In con- 
trast to the Goodson graphotype, the perforating machine of the 
electrotypograph does not use electricity. All its functions are 
purely mechanical, without compressed air or electric current. Mech- 
anism was substituted because of the inaccuracy of electric or other 
contacts established by the play of a keyboard, which produces vari- 
able pressure in rapid work. In their casting machine, on the con- 
trary, the inventors of the electrotypograph made a very judicious 
use of electric power; there the mechanical movement of the parts 
assures perfect contacts. Unlke the graphotype, the electrotypo- 
graph uses only 15 (instead of 60) electro-magnets. These are all 
of the same strength and have a resistance of 100 ohms, using a cur- 
rent of only 0.1 ampere under a potential of 10 volts. There is never 
but one electro-magnet in action at a time in the machine, and the 
duration of its excitement is less than one-twentieth of a second. In 
the most recent machines, a single electro-magnet automatically stops 
the machine in case of damage or trouble in operation arising from 
the negligence of the operator. Thus, the machine stops when the 
end of the perforated ribbon is reached. In this way the machine is 
automatic to such an extent that one workman can easily watch two 
miachmmes ~* > »*, 
IMPROVEMENTS AND RESULTS OF THE ELECTROTYPOGRAPH. 
Since the trials made by the journal Le Temps with the 1902 model 
of the electrotypograph—trials which were attended with complete 
success—important improvements have been made in the mechanism 
of the machine, and it has now advanced beyond the experimental 
stage. 
The new model has many and very important improvements over 
the 1902 model, among which are: A mechanism permitting the cast- 
ing at will of high or low spaces; the addition of letters with a pro- 
jecting face like V in italics; simplified construction in the justifica- 
