356 On the Construction of Theatres. 
an object of discussion, I trust that I may have an oppor- 
tunity of explaining what I propose ; and if any thing be 
adopted from my suggestions, that it may not be followed, 
without my being acquainted with the mode of execution. 
Many new attempts fail of their object by the introduction 
of additional ideas, that appear plausible ; or by the omis- 
sion of small circumstances, that seem in the original plan 
to be of no material consequence. 
In building a theatre, 
t. Security to the audience is the first and most neces- 
sary object. 
% Facility of ingress and egress. 
8. Facility of seeing and hearing. 
Convenience to the performers. 
5. Space for scenes, with proper openings for the ma- 
chinery. 
6. And lastly, expense. 
1. To ensure safety , common sense points out, that as 
little timber and as small a portion as possible of combus- 
tible materials should be employed. The outside w^lls 
should be constructed of stone — the coins of large blocks 
of stone closely jointed, depending upon their own bear- 
ings and not made apparently compact by mortar. Ericks 
for the internal structure should be made under proper 
Inspection, and not worked hastily up, to fulfil a contract. 
All the joists, rafters, and principals, and the framework 
of the partitions should be iron. The frame work of the 
yoof should be of the same metal, with a covering of cop- 
per. No plumber should be permitted to exercise his 
dangerous trade in the construction of any part of the 
building. 
It may at first sight appear, that the substitution of 
Iron for timber must be enormously expensive — and it 
would be enormous, if scientific care were not taken, to 
calculate the stress and strength of every part of the struc- 
