residual products, recharging and reclosing the retorts. There is
necessarily, therefore, less labor and cost in working, and as the gas
is cleaner or freer from impurities, purifying plant and material will
be correspondingly less. Oil gas is now employed for lighthouse
service in the illumination of the lanterns on Ailsa Craig and as
motive power in the gas engines connected with the fog horns at
Langness and Ailsa Craig lighthouse stations. It is also used largely
in the lighting of railway carriages. Various populous places are now
introducing oil gas for house service, and he felt sure that the
system is one which ought to commend itself for its future development
to the careful consideration and practical skill of the members of the
Gas Institute.

* * * * *

THE MANUFACTURE OF SALT NEAR MIDDLESBROUGH.[1]

[Footnote 1: Abstract of paper read before the Institution of
Civil Engineers, May 17, 1887.]

By Sir LOWTHIAN BELL, Bart., F.R.S.

The geology of the Middlesbrough salt region was first referred to,
and it was stated that the development of the salt industry in that
district was the result of accident. In 1859, Messrs. Bolckow &
Vaughan sank a deep well at Middlesbrough, in the hope of obtaining
water for steam and other purposes in connection with their iron works
in that town, although they had previously been informed of the
probably unsuitable character of the water if found. The bore hole was
put down to a depth of 1,200 feet, when a bed of salt rock was struck,
which proved to have a thickness of about 100 feet. At that time
one-eighth of the total salt production of Cheshire was being brought
to the Tyne for the chemical works on that river, hence the discovery
of salt instead of water was regarded by some as the reverse of a
disappointment. The mode of reaching the salt rock by an ordinary
shaft, however, failed, from the influx of water being too great, and
nothing more was heard of Middlesbrough salt until a dozen years
later, when Messrs. Bell Brothers, of Port Clarence, decided to try
the practicability of raising the salt by a method detailed in the
paper. A site was selected 1,314 yards distant from the well of
Messrs. Bolckow & Vaughan, and the Diamond Rock Boring Company was
intrusted with the work of putting down a hole in order to ascertain
whether the bed of salt extended under their land. This occupied
nearly two years, when the s