— 191 — 
0 【 inches viz., halves?, quarters, eighths, sixteenths, thirty seconds and sixty fourths : 
^°ikmen do not seem to understancl decimals, so ifc is better not to use them. 
マ id also the use of the development method, as it is beyond the comprehension of 
oulinavy workmen. The lengths of all main members should be measured on the 
awing then checked by calculation. 
'Vlien nuts are placed in a confined position, for instance pin nuts in jaws, care 
ould be taken that thero be ample room for them to turn iu, as it is very awkward 
a ud sometimes impossible to screw up a nut, wliicli is stationary, by turning tlie 
P 111 ; nuts in confined positions may be turned by hammering them eccentrically. 
仏 careful to design no connection in such a maimer tliat tliero will be rivets 
⑽ cannot be driven without iucouveaience. This remark is especially applicable 
o field rivetting. 
It must be borne in mind that, no matter liow carefully the bill of iron was 
P le paied, there will be many minor changes founcl necessary in making the working 
• rawi «gs; but, as a rule, such changes do' not materially affect the total weight of 
lr 如 m tlie bridge. 
