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139
Sulphuretted
Hydrogen.
Pressure.
exceed 35 grains in 100 cubic feet of gas. The former limit
imposed was 22 grains during six consecutive days, or 30 grains
on any one day.
The testing for sulphur impurities, other than sulphuretted
hydrogen has, however, been continued, and the average for the
year ended 31st March, 1908, was 2.6 grains in 100 cubic feet of
gas, with a minimum monthly average of 22.6 grains, and a
maximum monthly average of 27.6 grains, while the highest
amount of sulphur found in any one test was 33.3 grains on
February 16th, 1908. So far, therefore, the Wandsworth and
Putney Gas Company compares favourably, as regards sulphur
impurities, with the averages shown by the Metropolitan Gas
Companies during the same period. Owing to the removal of the
apparatus for repair during October, 1907, I am unable to furnish
an average for that month.
A curve, showing weekly averages of sulphur, is given in
Table III.
There has been no sulphuretted hydrogen found in any of the
testings made during the year ended 31st March,
1908.
The minimum pressure allowed between sunset and midnight
is that of equal to a column of water not less than
one inch in height; but the Company have usually
employed a pressure of about two inches in past years. During
the year ended 31st March, 1908, the pressure has, however, been
considerably higher. Although up to June 30th, 1907, it rarely
exceeded 3.o inches, there were some records of over 4.5 inches in
July, 1907. In August the average was nearly 4.3 inches, with a
maximum of 5.6 inches on August 22nd, while in September the
average was, 4.2 with a maximum of 5.i inches on September
20th. On October 4th the pressure-gauge registered 5.7 inches.
This pressure proved to be too great for the sulphuretted
hydrogen apparatus and the gas bubbled through the mercuryseal,
rendering further tests impossible for the time being. I at
once called ihe attention of the Council to the matter, and the
apparatus was removed and reconstructed so as to withstand a
sudden rise of pressure, which, however, I am glad to say did not
occur again during the remainder of the period ending 31st