The national era. [volume] (Washington [D.C.]) 1847-1860, 1851-07-17
MECHANISM. NO. 7.
BY JOSIAH HoLBRooK.

Two rght-auged isosceles trianges, by one
combination form square F.; by another, rhom-
bold; by third, another triangle of same shape,
though double the size. Each Of these can be
again combined in forms numberess and nameless.
Such an endless variety of combinations, all traced
back to the same simple elementary figure, must
render that figure Important to be understood
most Familiarity, at least by mechanics and house
keepers For the cultivation of taste in all young
minds it is probably equal to any other one thing
Several modes can be used to show the various
combinations ofthis one simple element of mechan.
ism. The most direct, perhaps is to draw a
square upon slate, say two-nch sides. That done,
draw diagonal line-da, the Greek Of through,
and gonia, corner-from corner to corner. That
done draw another Then bisect the square from
side to side by two lines, each passing through
the point of intersection Of the diagonal lines at
the centre Of the figure. These four lines will di-
vide the square into eight right-angled isosceles
trianges all precisely equal and alike also into
four squares, each an inch, OF one quarter Of the
square first drawn Each Of these squares, again
divided diagonally, will form double the number of
triangles, still retaining the same shape SINH
lar diagonal division can be carried to any extent
each division of course increasing the number of
squares, rhomboids and trangles. Such slate
exercise may be given to whole school at any
moment much to the entertainment of the pupils
! They almost Immediately give precision of eye
and hand truly surprising aiding most essentially
every species Of drawing especially maps, wri-
ting, and, directly or indirectly, nearly all the
subjects of school instruction The great pleasure
it affords, the precision of hand and eye it cult
Yates, the intimate acquaintance with the ee-
ments Of mechanism it gives, and the general
habits of attention il promotes, with the entire
ease with which it can at any moment be given to
a whole school, recommend this mechanical exer-
else for young hands as worthy of the special
attention both of teachers and parents.
The scale and dviders may also be brought
into use for more advanced exercises in the diyi-
sions and combinations of this same fgure-the
right-auged isoscees triangle. Connected with
these instruments, the pen may be used most
adyantageously, aiming especially at fine, smooth,
perfectly exact lines no blotting overrunning,
no variations from the same points of intersection
nothing but piece Of work showing the hand of
an artist
In addition to the scale and dividers, followed
by the pen, the brush and paints may be used for
the same illustrations in different forms. Another
mode especially fitted for young hands is by the
use of paper of two coors at least, in strong con-
trast say dark blue and bright yellow. This cut
by scissors into exact rght-snged isosceles TRAN
giles, aided by paste, can be 30 combined by six.
year-old hands as to show great beauty, at least
in view Of the makers also securing the admira-
ton of their friends These exercises, thus varied
as lessons in mechanism, have in them 80 much
attraction for young minds as to draw them with
entire certainty from almost any other amuse-
ment which may be offered them.
Experiments or several years past, Scholars
Fairsn or exhibitions Of the artstcal skill of the
pupils, have been held by the New York schools
semi-annually In very many cases pupils thus
exhibiting their work have been sought for TO fill
places providing for them profitable, useful, and
respectable situations. BY similar work, a lad in
Washington now occupies place as draugh's-
man in the coast survey Office. Several other boys
are making rapid progress in a course certain to
lead them to places which it will be difficult to fill
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