CO129-290 - Governor Sir Blake - 1899 [1-4] — Page 53

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ly difficult in the tropics to maintain such roofs watertight,

exposed as they are to extremes of temperature.Guttering and

down pipes should be designed for excessive falls of rain, on

one occasion three inches an hour for three consecutive hours

has been measured in Hong-Kong, and, sixteen inches in 7 hours

and 27 inches in 24 hours.

13. Granite of excellent quality is plentiful

in the Colony, and though the cost of dressed granite masonry

is about double that of brickwork, it would be desirable to use

the former largely for the facing at least of the buildings.

14. Special material for the covering of the

dome will have to be obtained from England and should he de-

signed and specified by the architects.

15.

The thickness of tiled roofing including

the row of mortar with which the joints of the adjacent rows

of tiles are covered is 9 inches. The tiles are 9 inches wide

and the common rafters or battens on which they are laid are

spaced 9 inches centre to centre. The weight of the tiling

when wet is 42 lbs per square foot and when dry 31 lbs.per

square foot. The strength of the timber, such as would he used

for purlins or common rafters is nearly equal to that of teak

as given by Molesworth in his value of K (co-efficient of rup-

ture) for rectangular heams,

(98.) R.D.ORMSBY,

16.11.98.

Dir. of Public Works.