Description of the Great Chimney at St Rollox. 219 
made a principle not to bribe any one to undertake the job. 
The men worked at wages of 5s. per day, or little more than 
their ordinary wages. They were steady, sober, active men ; 
and credit is due to them for the excellent manner in which 
they did the work. Mr Gordon or Mr Hill went up with the 
machine each day; and, after careful examination and deli- 
beration, concluded that the rent is an effect of expansion 
from heat. Though the fissure was found in one place to 
be 2 inches wide, and its average width to be nearly 1 inch, 
yet the nature of it was such, that a rod could not be put 
through the fissure to the inside of the chimney. It would 
have been very desirable to have got a thermometer into the 
interior ; but not having succeeded in getting it through the 
fissure, the expedient of driving a hole for the purpose was 
not adopted at the time, from its being inconvenient; and 
so the opportunity was lost. It may be mentioned, however, 
that red-hot matter has been more than once observed pro- 
jected in a column from the top of this 432 feet high chim- 
ney. The temperature in the chimney, near the top, is pro- 
-bably seldom under 600° F. 
Description of Climbing Machine. (Plate V1). 
‘Fig. 1. is a side view. 
... 2. is a back view. 
... 3. a plan across the windlass. 
The frame, which was as light as possible, consistent with proper 
strength, was about 10 feet high, 3 feet deep, and 4 feet wide; the 
beams next the stalk projected about 15 inches further at each end. 
W is the windlass, worked by the ratchet-handles HH. PP, two pul- 
‘lies fixed to windlass, round which the ropes were wound when the 
machine was ascending. L L, the lewises, securely fixed into the chim- 
ney, and to which the ropes were hooked. The heads of these lewises 
were bent at a right angle, so as to overlap the long plates II, by which 
means the machine was held close to the chimney. F FF F, four fric- 
tion-rollers, to prevent the machine from rubbing against the stalk. SS, 
two short chains, which were used for holding up the machine while the 
ropes RR were being shifted to a new set of lewises, for another lift. 
K K, two long racks, which were hung on pins at O0O.—They worked 
into, or against, the two under lewises, and were used in order to pre- 
vent the machine from falling, in case any accident should happen to 
_the ropes. 
By working the handles backwards and forwards, the machine. was 
sent up a lift of 5 feet in a few minutes. Two catches (not shewn in 
the drawing) worked into the teeth of the windlass wheels, and pre- 
