e spiral as made for
England is of 5/8 in. steel rod, because English people would not be
inclined to try what is really sufficient in most cases, namely, a mere
wire. The working of this spiral as a conveyer is simply magical. A 6 in.
spiral delivers 800 bushels per hour at 100 revolutions per minute, and
more in proportion at higher speeds. A little 4 in. spiral delivers 200
bushels per hour at 100 revolutions per minute. It seems to act as a mere
persuader. The spiral moves a small quantity, and sets the whole contents
of the trough in motion. In fact, it embodies the great essentials of
success, namely, simplicity, great capacity for work, and cheapness. It is
the invention of Mr. J. Little, and is made by the Anti-friction Conveyer
Company, of 59 Mark Lane, London.

[Illustration: THE ANTI-FRICTION CONVEYER WITH CASING OR TROUGH--END
VIEW WITH HANGER.]

Since the days of Archimedes, who is credited with being the inventor of
the screw, there has not been any improvement in the principle of the worm
conveyer. There have been several patents taken out for improved methods of
manufacturing the old-fashioned continuous and paddle-blade worms, but Mr.
Little's patent is the first for an entirely new kind of conveyer.

* * * * *

STUDIES IN PYROTECHNY.

[Footnote: Continued from SUPPLEMENT, No. 583, page 9303.]

II. METHODS OF ILLUMINATION.

_Torches_ consist of a bundle of loosely twisted threads which has been
immersed in a mixture formed of two parts, by weight, of beeswax, eight of
resin, and one of tallow. In warm, dry weather, these torches when lighted
last for two hours when at rest, and for an hour and a quarter on a march.
A good light is obtained by spacing them 20 or 30 yards apart.

Another style of torch consists of a cardboard cylinder fitted with a
composition consisting of 100 parts of saltpeter, 60 of sulphur, 8 of
priming powder, and 30 of pulverized glass, the whole sifted and well
mixed. This torch, which burns for a quarter of an hour, illuminates a
space within a radius of 180 or 200 yards very well.

The _tourteau goudronne_ (lit. "tarred coke") is merely a ring formed of
old lunt or of cords well beaten with a mallet (Fig. 10). This ring is
first impregnated with a composition formed of 20 parts of black pitch
and 1 of tallow, and then with another one formed of equal parts of
black pitch and resin. One of these torches will burn for an hour in
cal