44 



HYDROGRAPHICAL SURVEYING 



[chap. I. 



Mounting 



Loose 



Sheets. 



Joining 

 Sheets. 



The stock of paper should be kept in tins in the driest 

 place in the ship, which is probably in or near the engine- 

 room. 



The mounting of the backed sheets supplied from the 

 Stationery Office is usually very well done, and it saves time 

 to use these ; but as it may be necessary for the surveyor to 

 mount sheets himself, the method will be described. 



The holland or calico on which the paper is to be mounted, 

 and which must be in one piece and larger than the board, 

 must be lightly damped. It is then stretched over the board 

 and tacked to the edges, care being taken to stretch it equally 

 and squarely A\dth the woof and warp. Rub plenty of strong 

 paste into it with the hand, and see there are no lumps left. 

 The sheet of paper must be well damped with a sponge on both 

 sides, taking care to dah only, on the side on which the work 

 is to be done, and not nib with the sponge. The sheet is 

 then carefully Ufted by the four corners, one edge laid on the 

 holland while the rest is kept clear of it, and the paper gently 

 rubbed on to the board with a soft handkerchief, the paper 

 being gradually lowered, so as to allow air bubbles to 

 escape. It will take two people to do this, and it must be done 

 with great care. It must be left to dry by itself, and no hot 

 sun should be allowed to get to it, so that it may dry evenly. 



If the plotting sheet is to be formed of more than one piece 

 of paper the edges of the paper which will overlap must be 

 fined down. This is done in the first instance by scraping 

 with a sharp knife, having drawn a line on the paper where the 

 overlapping will come, and then finishing off with ink eraser. 

 The piece that is to be uppermost must be scraped on the 

 under-side only, and the undermost one on the upper side, so 

 as to make, in fact, a scarph. This will lessen the appearance 

 of a joint, and the inconvenience of ruling lines hereafter 

 over it. 



