fecuring Buildings againjl Fire. 891 
and bedded found into the foft rough plafter. For this 
reafon, no more of this firft coat of rough plafter ought 
to be laid on at a time than what can be immediately 
followed with the fecond layer of laths. 
The laths of this fecond layer ought to be laid as clofe 
to each other as they can be, to allow of a proper clench 
for the rough plafter. 
The laths of the fecond (b> layer may then be plaftered 
over with a coat of the fame kind of rough plafter, or it 
may be plaftered over in the ufual manner. 
§ 16. The third method, which is that of inter-Jecur- 
ing , is very fimilar, in molt refpedls, to that of under - 
flooring ; but no fand is afterwards to be laid upon it. 
Inter-fecuring is applicable to the fame parts of a build- 
ing as the method of extra-fothing juft defer i bed ; but it 
is not often neceffary to be made ufe of. 
§17.1 have made a prodigious number of experi- 
ments upon every part of thefe different methods. I 
caufed a wooden building to be conftru6ted atChevening, 
in Kent, in order to perform them in the moft natural 
manner. The methods of extra-lathing and double 
under-flooring were the only ones made ufe of in that 
building. 
(b) If a third layer of laths be immediately nailed on, and be covered with 
a third coat of rough plafter, I then call the method treble-lathing-, but this 
method of treble-lathing can almoft, in no cafe, be required. 
5 S 2 
On, 
