fore its altitude, are altered. A portion
of the vertical post up and down which the crane climbs forms the base
of a triangle, and a portion of the jib, together with the stay, forms
the remaining two sides. Hence, by causing the foot of one or the other
to travel upward, by means of the worm gearing, the upper end of the jib
is either elevated or depressed.

The concrete elevator, which is also combined with the scaffold,
consists of a series of buckets carried upon two parallel endless chains
passing over two pairs of wheels. On the under frame is fixed a hopper,
into which is thrown, either by hand or from a concrete mixer running
upon the rails, the material to be hoisted, and from which it gravitates
into a narrow channel, through which pass the buckets (attached to the
chain) with a shovel-like action. The buckets, a motor being applied to
one pair of wheels, thus automatically fill themselves, and on arriving
at top are made to tip their contents, and jar themselves, automatically
into a hopper by means of a small pinion, keyed to the shaft by which
they are attached to the endless chain, becoming engaged in a small rack
fixed for that purpose. From the upper hopper the material is taken away
to the required destination by means of a worm working in a tube. For
varying heights, extra lengths of chain and buckets are inserted and
secured by a bolt passed through each end link, and secured by a nut. By
using this scaffold, a saving in plant, cartage, and labor is effected.
The elevator may also be used for raising any other material besides
concrete.

Such is the new system of concrete construction and scaffolding of
Messrs. West, which appears to be based on sound and reasonable
principles, and to have been thoughtfully and carefully worked out, and
which moreover gives promise of success in the future. We may add in
conclusion that specimens of the work and a model of a scaffold
are shown by Messrs. West at their stand in the Inventions
Exhibition.--_Iron_.

* * * * *

[Illustration: ALBANY BUILDINGS SOUTHPORT. E.W. JOHNSON, ARCHITECT.]

* * * * *

THE BLUE PRINT PROCESS.

R.W. JONES.

1. Cover a flat board, the size of the drawing to be copied, with two or
three thicknesses of common blanket or its equivalent.

2. Upon this place the prepared paper, sensitive side uppermost.

3. Press the tracing firmly and smoothly upon this pape