as well as in their explosive qualities; the late Minister of War in
Austria in 1862 stated to me that he had ordered four hundred cannon for
gun-cotton, and six months after he stated that he had ordered all
the cannon to be changed and adapted to powder, in consequence of
spontaneous combustions; much less is known of nitro-glycerin than of
gun-cotton, and probably several varieties of this article may be formed
as of gun cotton; this would explain cases of spontaneous explosion; if
the nitro-glycerin is not carefully washed to get rid of the acid, a
gradual decomposition will ensue, producing gases, which, if the vessel
be closed, will explode; my opinion is that nitro-glycerin should be
used in the most careful hands; do not think I would put it in the hands
of a common laborer for blasting purposes; it is less dangerous in a
frozen than a liquid state; I think concussion would explode frozen
nitro-glycerin.

* * * * *




HISERT'S ADJUSTABLE CULTIVATOR TOOTH.


The object of the device exhibited in the engraving is to allow the
teeth of a cultivator to turn slightly and avoid obstructions, while
they will follow at all times the line of draft, so that in turning the
cultivator there is no risk of breaking the teeth or their shanks, or
of overturning the implement. The cultivator blade, A, may be of any
desired form, and it is secured to the curved shank, B, which is pivoted
by a bolt to the beam, C. On the under or lower side of the beam is an