368 
Method of obviating 
and, had the operation of lifting taken less time, the 
number would have been considerably increased; for 
the saving of a day is very frequently the cause of sav- 
ing a spring tide, which makes the difference of a fort- 
night. The importance of this expedition, in time of 
war, cannot be sufficiently estimated. 
This invention may be applied with great advantage, 
whenever it is necessary to erect shores, to support any 
great weights, as, for instance, to prop up a building dur- 
ing the repair of its foundation, &c. Captain Wells, of 
his majesty’s ship Glory, of 98 guns, used wedges of 
Mr. Sepping’s invention for a fid of a top-gallant mast 
of that ship. In 1803, the top-gallant masts of the De- 
fence, of 71 guns, were fitted on this principle by Mr. 
Seppings : and, from repeated trials, since she has been 
cruizing in the North Sea, the wedge fids have been 
found in every respect to answer. 
But it is Mr. Sepping’s wish that it should be under- 
stood, that the idea of applying this invention to the fid 
of a top-gallant mast originated with captain Wells, who 
well understood the principle, and had received from him 
ft model of the invention. 
When it is required to strike a top-gallant mast, the 
top ropes are hove tight, and the pin which keeps the ho- 
rizontal wedges in their place is taken out, by one man 
going aloft for that purpose ; the other horizontal wedge 
is worked in the fid, as shown in the drawing and model 
that accompany this statement. The upper part of the 
fid hole is cut to form the vertical wedge. The advan- 
tage derived from Adding top-gallant masts in this way is, 
that they can be struck at the shortest notice, and without 
slacking the rigging, which is frequently the cause of 
springing and carrying them away, particularly those with 
long pole heads. The angle of the horizontal wedges 
for the fids of masts should be about twenty degrees. 
