SHOUT NOTES OX PROFESSIONAL SUBJECTS. 
179 
114. Description of the operation of Straightening the Brick 
Chimney-shaft of the Gas Works at the Royal Arsenal, Woolwich, 
in March, 1874, under the superintendence of Bt.-Lieut.-Colonel 
Scratch ley, R.E., Inspector of Works, Manufacturing Depart¬ 
ments, and Lieut. Watson, B.E. 
The following description of this interesting operation may prove of service; and 
as it can without doubt be applied to chimney-shafts of any height, it will, in most 
eases, be worth a trial before adopting the expensive course of rebuilding shafts 
which have become inclined. 
The operation at the Arsenal was carried out by Mr. Ralph Hall, of 126, North 
Frederick Street, Glasgow—a well-known “ Steeple Jack” who has had great 
experience in all matters relating to defective chimney-shafts, the repair and refixing 
of their caps, and lightning conductors. 
The price paid for the work was £50—a very moderate sum, when it is considered 
that the cost of rebuilding the chimney, with a good pile foundation, and removing 
the old shaft, was estimated at £650. 
It will be seen that the operation is very simple and apparently unattended with 
any risk, but the operator must possess great coolness and experience. 
The Arsenal shaft which is 100 ft. high, was erected in 1860. 
From borings taken prior to its erection, it was found that the subsoil consisted 
of clay resting on an inclined bed of peat, situated at a considerable depth below the 
surface of the ground. 
With this bed of clay it was considered at the time unnecessary to have a pile 
foundation, and a mass of blue Lias lime concrete, 30 ft. square and 8 ft. thick, 
was provided. 
Soon after the chimney was completed, it was observed to be inclining from the 
perpendicular, and in December, 1861, it was leaning over 19 ins. to the south, and 
24 J ins. to the west. 
Observations were taken with a theodolite, and continued at intervals up to the 
middle of 1873, when it was found that the inclination of the chimney had in¬ 
creased to 33 \ ins. to the south, and 42J ins. to the west. 
The increase in the inclination was not uniform, but became more rapid between 
the years 1871 and 1873 ; consequently—although the limit of safety (72 ins. of 
inclination) had not been reached—it was decided to attempt to straighten the 
chimney rather than to rebuild it. 
It is difficult without a careful examination of the foundations, which would be 
a costly matter, to assign an exact cause for their failure ; but it is quite possible 
that the inclined bed of peat, being of an unequal thickness, may have become com¬ 
pressed by’the weight of the, chimney—estimated at about 20 tons. 
After consultation with Mr. Hall, it was determined to cut out the brick-worlc at 
top of the chimney base, where its thickness is 2 ft. 3 ins. at the angles "and 1 ft. 
'ns. at the sides, exclusive of the fire-brick lining to the fiue, which as it was 
no g out had to be removed. 
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