Isambard Kingdom Brunel to Faraday   6 March 1855¹

Tuesday | March 7 [sic]

My dear Sir

I want to test the efficiency of ventilation of a room built as an experimental or specimen wardroom for hospitals to be sent out ready made to the East².

The room is 70 ft long 21 ft wide and a good height - it is ventilated by mechanical means driving air rising up through the floor at six places - along the centre and escaping through the roof - the air is driven in by a fan placed outside the room.

Can I by some easy means fill this room with a very visible smoke gas or dusty air (perhaps by driving it in with the fan -) - and then watch the displacement of this visible atmosphere by the fresh air? or could you kindly suggest some better mode or tell me how to carry out this one - it is important that no difference of temperature should assist or impede the ventilation as the object is to imitate what will have to be done in a hot climate where the air injected will probably be very little cooler than that of the chamber[.]

I know that I need not say anything to induce you to assist anybody in doing a usefull thing but nevertheless I will tell you that this is a case peculiarly claiming assistance. I am engaged in designing and constructing with all dispatch a large quantity of hospital accommodation to be sent out and erected near the seat of war - while the materials are being prepared this sample ward is made and will be erected by Thursday next³ at Paddington for the inspection of the War Minister and the medical authorities and I want on that day or on Friday to test the ventilation. I will call on you at any time you may name today or Wednesday to take some instruction if you will be kind enough to give your thoughts to the subject[.]

Yours faithfully | I.K. Brunel

Endorsed by Faraday: Wednesday 1/2 p3 or 4 o clk