1838 J Memorandum regarding Syrian or Cylinder Roofs, 383 



rains having completely saturated the mud and earth of the centre- 

 ings before the arches could be completed, the former became when 

 dry so caked to the interior of the roof, that, after the severe blows 

 of a crow-bar proved ineffectual, a hammer and chisel were resorted 

 to. Many of the cylinders were broken at the smaller end by this 

 violent process ; yet (notwithstanding several men were walking over 

 lieaid at the same time) not a crack occurred. It must be remarked 

 that, at certain intervals along the roof, and at each end, arches Of 

 solid masonry, one and a half feet broad and nine inches deep, are turned 

 from wall to wall as aids and binders to the cylinders which were built 

 up between them, and at the same time : so that in a building sixty feet 

 long forty-two feet Only were really composed of cylinders. The follow- 

 ing memorandum, taken on the spot, may serve to facilitate calculations 

 for various spans, but as the actual cost of material will vary much at 

 different places, and the workmen will necessarily at first be rather 

 slow in their operations, while such strict and constant surveillance 

 may not be always attainable, the actual expenditure will be a little 

 greater perhaps, though the quantities ought not much to exceed the 

 estimate I have formed. Th^ operations connected with the construc- 

 tion of these roofs, are really so very simple throughout, and ordinary 

 bricklayers so promptly comprehend them (those at Bangalore being 

 now highly expert in the matter), that it is surprising such excellent 

 permanent coverings to houses, godowns and stabling have not be- 

 come more general— one-half the weight of a tiled roof (as subsequent 

 statements will prove) one-third cheaper than the same formed of 

 teak-wood rafters, reapers, kc. &c. one-half the price and weight of 

 a terrace roof, while in duration, cleanliness, coolness and appear- 

 ance it far exceeds every other, the Syrian or cylinder roof 

 on the score of comfort and economy, deserves the highest patronage 

 in India, where white ants, rats and vermin are destructive and 

 annoying. 



For a room 33 feet x 21 feet— simicircular arch = 1088 superficial 

 square feet. 



Cylinders— 5 inches largest diameter, 4| inches smallest diameter. 



^ (Now in the above curve there are 32*97 feet, or 395-64 

 Vinches,and it would require 70 cylinders (5 inc. diameter) 

 60 y to go over but with chunam and deducting for solid brick 

 ^and chunam curves at the haunches (about 3 feet on each 

 J side) 60 only were found to be necessary (quarter less 

 ^ than the whole estimated). 



f Again there are four brick and chunam binders 1 foot 

 70 •< broad each, and therefore 70 cylinders only were used in 

 ( the length. 



