Securing Buildings againjl Fire . 889 
§10. When the rough plafter-work between the joifts 
has got thoroughly dry, it ought to be obferved, whether 
or not, there be any fmall cracks in it, particularly next 
to the joifts. If there are any, they ought to be wafhed 
over with a brufli, wet with mortar-wajh , which will 
effectually clofe them; but there will never be any 
cracks at all, if the chopped hay and the quick lime be pro- 
perly made ufe of. 
§ 1 1. The mortar- wafli I make ufe of is 'merely this. 
About two meafures of quick lime, and one meafure of 
common fand, fhould be put into a pail, and fhould be 
well ftirred up with water, till the water grows very 
thick, fo as to be almoft of the conliftency of a thin jelly. 
This wafli, when ufed, will grow dry in a few minutes. 
§ 12. Before the flooring boards are laid, a fmall 
quantity of very dry common fand fhould be ftrewed 
over the rough plafter-work, but not over the tops of 
the joifts. The fand fhould be ftruck fmooth with an 
hollow rule, which ought to be about the length of the 
diftance from joift to joift, and of about one eighth of an 
inch curvature; which rule, palling over the fand, in 
the fame direction with the joifts, will caufe the fand to 
lay rather rounding in the middle of the interval between 
each pair of joifts. 
The flooring boards may then be laid and fattened 
down in the ufual manner; but very particular attention 
Yon. LXVIII. 5 S muft 
