A monthly technical report containing details of the following experiments:

Exp. 680 Wireless Telephony: Air to Tank An aerial that combines strength, compactness and electrical sensitivity consists of a tube that straddles the tank at right angles to its length, see Fig. I, Diagram No. 1158. Electrical connections are shown in Fig. II.

Exp. 683 Tonic Train Attachment for 0.5 K.W. Marconi Transmitter. The experimental work was carried out on the 0.5 K.W. Marconi Fortress Set. Fig. I, diagram No. 1157 shows the ordinary connections, and Fig. II shows the alterations in connections and the Tonic Train attachment.

Exp. 674 Tests on U, O 3 Cells. An endurance test lasting 3 hours and 55 minutes was made at an altitude of 17,000 to 18,000 feet. The attached chart gives readings every 300 minutes.

Exp. 608 Direction Finding Investigation of noises produced by Lucas Generators when using Maximum method of D.F. on Handley Page Machines. See layout of generator substitute resistance switch, diagram 1159.

Exp. 688 Twin Trailing Aerials. Experiments have been carried out to determine the best type of Twin Aerial from a purely mechanical point of view.

Exp. 527 Tests of Various Types of Head Receiver. The efficiency of a head receiver is greatly dependent upon the type of amplifier with which it is used. The U.S. Signal Corps pattern of head receiver has been adopted as the standard for R.A.F. work.

Exp. 527 Head Receiver Head Band This headband has been designed to work in conjunction with the Marr-Reddaway earpiece already patented. See photograph No. 132 on page 8.

Exp. 637 Slipstream Air Speed Measurements. The measurements detailed in the chart below are a continuation of test described in the Monthly Technical Report for May 1918, page 20.

Exp. 676 Measurements of Air Temperatures at Various Altitudes. The object of the tests was to obtain a rough idea of the temperature to which accumulators are subjected during flights at great altitudes. This is in continuation of tests in the Monthly Technical Report for September, Page 35.

Exp. 608 Direction Finding D.F. Method using the Bellini-Tosi system combined with a modified form of the R.A.F. Method. The connections are shown in diagram No. 1160.

Exp. 608 Direction Finding Further report on W/T D.F. Gear on Flying Boat F. 3 N 4236.