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Experiment X.

        The following experiments—X, XI, and XII— were made without the use of fan
or tubes. The gas was produced in the room itself. First of all the sulphuric
acid (commercially strong, specific gravity 1.83) was mixed with water (2 parts
of sulphuric acid to 4 parts of water) generating heat. The mixture was made in
a china vessel when small amounts were used and in a kerosine oil tin when large
amounts were necessary. Then one part of potassium cyanide (100 per cent.
Burgoyne Burbidges' Double Salt, for analysis see pages 2 and 3 of Report) was
put in and the room at once quitted and the door shut.

        In Experiment X a small, very air-tight godown was chosen, of about 346
cubic feet capacity.

        One oz. potassium cyanide 2 ozs. sulphuric acid and 4 ozs. water were mixed.
The exposure was for 40 minutes. The doors were then opened, but fumes of
gas still were seen o be coming off.

        The room was entered 15 minutes later. The fleas were examined at once
and also two hours later.

E