The error in such reading does not
reach half a millimeter, and, as a suitable height of the apparatus
permits of having columns that vary between 13 and 30 centimeters, an
error of this kind is but 1-300. This is the limit of precision of the
method.
The clamp might be advantageously replaced by a glass cock, or, better
still, A might terminate in a rubber bulb; and a lateral tubulure
might be fixed to the pipette, and be closed with a rubber stopper.
This little apparatus is more easily maneuvered than any of those that
have hitherto been devised upon the same principle. It is capable also
of replacing areometers in ordinary determinations, since it permits
of correcting the error in capillarity that is neglected in
instruments; and, moreover, one can, when he desires to, easily verify
for himself the accuracy of the graduation.--_La Nature._
* * * * *
USEFUL BAGS, AND HOW TO MAKE THEM.
By JOHN T. HUMPHREY.
Since the papers on "Boot and Shoemaking," in vol. i. of _Amateur
Work_, illustrated, I think nothing relating to the leather trades has
appeared in it; and as there must be many among the readers of this
magazine who have a desire to dive deeper into the art of manipulating
leather into the various articles of utility made from that material,
I will endeavor in the series of articles of which this is the
commencement to furnish them with the necessary instructions which
will enable them to do for themselves many things which now are left
undone, or else have to be conveyed miles to some town where the
particular business, or something akin to it, is carried on.
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