Copy letter from Robert William Frederick Harrison to H F Coward, HM Office of Works 'I am much obliged by your note of yesterday about the hoisting of the fan. I learn from a letter from Messrs Davidson & Co makers of the "Sirocco" fan, who are supplying the ventilating fan, that the total weight of the combination will amount to 10 cwt, 3 qrs, and 17 lbs; but the heaviest single item appears to be the motor, weighing 5 cwt and 20 lbs. I understand that the makers, who are going to erect the fan, will bring a tackle for hoisting the parts and I trust that there will be no difficult in strengthening the derrick sufficiently to bead the necessary weight.' 28 July 1911