CEMENTS. SOI 



Boiled linseed-oil, litharge, red and white lead, 

 mixed together to a proper consistence, and ap- 

 plied on each side of a piece of flannel previously 

 shaped to fit the joint, and then interposed be- 

 tween the pieces before they are brought home 

 (as the workmen term it) to their place by the 

 screws or other fastenings employed, make a close 

 and durable joint. 



The quantities of the ingredients may be'varied 

 without inconvenience, only taking care not to 

 make the mass too thin with oil. It is difficult in 

 many cases instantly to make a good fitting of large 

 pieces of iron work, which renders it necessary 

 sometimes to join and separate the pieces repeated- 

 ly, before a proper adjustment is obtained. When 

 this is expected, the white-lead ought to predomi- 

 nate in the mixture, as it dries much slower than 

 the red. A workman, knowing this fact, can be at 

 little loss in exercising his own discretion in re- 

 gulating the quantities. It is safest to err on the 

 side of the white-lead, as the durability of the 

 cement is no way injured thereby, only a longer 

 time is required for it to dry and harden. 



When the fittings w'ill not admit easily of so 

 thick a substance as flannel being interposed, 

 linen may be substituted, or even paper or thin 

 pasteboard. 



This cement answers well also for joining broken 

 stones, however large. Cisterns built of square 

 stones, put together with this cement, will never 

 leak or want any repairs. In this case the stones 

 need not be entirely bedded in it : an inch, or 

 even less, of the edges that are to lie next the 

 water, need only be so treated ; the rest of the 

 joint may be filled with good lime. 



