When the tube is screwed in the socket, the powder mixes with the oleic
acid. The water coming in at first makes the linseed powder viscid.
Later the steam forming the oleate of lime and the oleate of lead,
on its way to the outer air, presses it in the holes and closes them
perfectly.
After a year in use the tubes can be unscrewed with ease, and the screw
threads are perfectly smooth.
With this kind of packing only one exception must be made--that is, it
is only tight under pressure; condensation or vacuum must be thoroughly
avoided.--_Chem. News_.
* * * * *
LUMINOUS PAINT.
In answer to various inquiries concerning the manufacture of this
article, we give herewith the process of William Henry Balmain, the
original discoverer of luminous paint, and also other processes. These
particulars are derived from the letters patent granted in this country
to the parties named.
Balmain's invention was patented in England in 1877, and in this country
in 1882. It is styled as Improvements in Painting, Varnishing, and
Whitewashing, of which the following is a specification:
The said invention consists in a luminous paint, the body of which is a
phosphorescent compound, or is composed in part of such a compound, and
the vehicle of which is such as is used as the vehicle in ordinary paint
compounds, viz.
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