498 



Prof. R. Threlfall and Mr. J. F. Adair. On the 



The Experiments. 

 The Site and General Arrangements. 



Through the kindness of the military authorities we were allowed 

 to use the torpedo station at Berry's Bay, in the harbour of Port 

 Jackson, as the base of operations. This bay had the advantage of 

 deep water close to the shore, of being comparatively quiet, and 

 within about an hour's journey of the University. The Sydney- 

 Marine Board with great courtesy allowed us to use their steam- 

 lauuches for the purpose of getting to the ground, it being out of the 

 course of the ferry-boats. The general plan of the water and coast-line 

 will be understood from an examination of the chart (Plate 3) kindly 

 prepared for us by Mr. R. J. A. Roberts, who also undertook the sur- 

 veying of the distance between the observing stations. We desire to 

 express our indebtedness to Mr. Roberts, for his very accurate deter- 

 minations to be referred to hereafter. The general disposition of the 

 arrangements was as follows : — Two piles, each about 45 feet long, 

 were driven into the mud of the sea-bottom at the stated distance 

 apart, and about 40 yards from the shore. To these piles were 

 attached the apparatus for recording the arrival of the disturbance 

 due to the explosions; the connexions with the shore were made by 

 means of two lengths of armoured cable, kindly lent to us by the 

 officer commanding the torpedo corps. At first We tried to use over- 

 head wires supported on telegraph poles, and running from the piles 

 to the shore ; these, however, were so systematically carried away by 

 passing steamers, that they had to be abandoned. 



In a portable constructor's house on the wharf we erected the 

 pendulum chronograph, to be described shortly, and there established 

 the arrangements for firing the charges and working the recording 

 apparatus. 



About a year was spent in experimenting with different forms of 

 apparatus for recording the arrival of the disturbance. Three forms of 

 " gauge " were devised, tested, and abandoned before the ultimate 

 form was hit upon. Considerable difficulty was also experienced in 

 avoiding missfires, as we desired to avoid complicating matters by 

 using heavy cases for our torpedoes. At one time work was entirely 

 suspended for three months, as we could not get any guncotton, and 

 were not allowed to store the dynamite which we could buy in the 

 market ; guncotton cannot be procured here except through courtesy 

 of the Government. The same remark applies to detonators, which 

 we were forced to devise a means of manufacturing for ourselves. 

 Finally, owing to the good offices of Major Penrose, R.E., we obtained 

 a supply of 100 lb. of guncotton from the Government, and several 

 boxes of detonators, for which we desire to record our thanks. In 

 our opinion any work of the kind should not in the future be under- 



