ion of the blind.

The Braille alphabet consists of varying combinations of six dots in an
oblong, of which the vertical side contains three, and the horizontal
two dots.

. .
. .
. .

There are 63 possible combinations of these six dots, and after the
letters of the alphabet have been supplied, the remaining signs are used
for punctuation, contractions, &c.

"For writing, a ruler is used, consisting of a metal bed either
grooved or marked by groups of little pits, each group consisting of
six; over this bed is fitted a brass guide, punched with oblong holes
whose vertical diameter is three-tenths of an inch, while the
horizontal diameter is two-tenths. The pits are arranged in two
parallel lines, and the guide is hinged on the bed in such a way that
when the two are locked together the openings in the guide correspond
exactly to the pits in the bed. The brass guide has a double row of
openings, which enables the writer to write two lines; when these are
written, he shifts his guide downwards until two little pins, which
project from the under surface at its ends, drop into corresponding
holes of a wooden board; then two more lines are written, and this
operation is repeated until the bottom of the page is reached. The
paper is introduced between the frame and the metal bed. The
instrument for writing is a blunt awl, which carries a little cap of
paper before it into the grooves or pits of the bed, thereby producing
a series of little pits in the paper on the side next the writer. When
taken out and turned over, little prominences are felt, corresponding
to the pits on the other side. The reading is performed from left to
right, consequently the writing is from right to left; but this
reversal presents no practical difficulty as soon as the pupil had
caught the idea that in reading and writing alike he has to go
_forwards_.

"The first ten letters, from 'a' to 'j,' are formed in the upper and
middle grooves; the next ten, from 'k' to 't,' are formed by adding
one lower back dot to each letter of the first series; the third row
is formed from the first by adding two lower dots to each letter; the
fourth row, similarly, by adding one lower front dot.

"The first ten letters, when preceded by the prefix for numbers, stand
for the nine numbers and the cipher. The same signs, written in the
lower and middle grooves, instead of the upper and middle,