On the occasion of the Great Exhibition in 1851, the characters 
and figures shown in fig. 27 were engraved by Mr. Eroment, 
within a circular space equal to that shown at c in fig. 25. 
32. As the method by which these marvellous effects are pro¬ 
duced is not yet patented or made public, we are not at liberty to 
explain its details; hut it may he stated generally to consist of a 
mechanism hy which the point of the graver or style is guided hy 
a system of levers, which are capable of imparting to it three 
motions in right lines which are reciprocally perpendicular, two 
of them being parallel, and the third at right angles to the surface 
on which the characters or design are written or engraved. The 
combination of the motions in the direction of the axis parallel 
to the surface on which the characters are engraved or written, 
73 
FROMENTS MICROSCOPIC WRITING. 
circle of glass, the 40th of an inch in diameter, less, therefore, by 
one third than the small white spot c, fig. 25 ; the sentence which, 
when magnified in its linear, 120, and in its superficial dimen- 
sionsj 14400 times, presented the appearance shown in fig. 26. 
Fig. 26. 
