Notes on the Radiometer. 67 



Art. II. — Notes on the Radiometer. 

 By R. L. J. Ellery, Esq. 



[Read 11th May, 1877.] 



Art. III. — On the Improvement of the Port of Melbourne. 

 By T. E. Rawlinson, C.E. 



[Read before the Royal Society of Victoria, 8th June, 1876.] 



In resuming the subject of a paper read before the 

 members last session on proposed works for the improve- 

 ment of the Port of Melbourne, I purpose replying, as far 

 as possible, to questions asked and objections raised at the 

 time and since to certain features of the proposed scheme. 



These questions and objections appear to resolve them- 

 selves into the following : — 



1st. The data on which I assume the width of 1000 feet 

 as necessary for the proposed new channel and basin. 



2nd. The oft repeated allegation that the River Yarra 

 has debouched at various times at several places between 

 St. Kilda and the present entrance at Williamstown. 



3rd. That the estimated total cost is far in excess of our 

 present means. 



In replying to the first I must remind members that I 

 stated the width assumed was based on certain generali- 

 sations, and subject to modification if necessary on receipt 

 of accurate data as to the amount of flood discharges 

 down the Yarra ; but although to this extent empirical, it 

 was in a large measure based on a knowledge of the exten- 

 sive discharge of flood waters over the St. Kilda-road^ 

 between the Prince's Bridge approach, and the Immigration 

 Barracks Hill, additional to the heavy discharge through 

 the Prince's Bridge and the Dry Arch south of it. In addi- 

 tion to this evidence there was the 200 feet span of Church- 

 street Bridge flooded to a great height, through which 

 the water tore in a torrent, destroying the sheet piling and 

 roadway underneath ; while at Johnston-street Bridge, with 

 an opening of 175 feet, the water rose to a gTeat height 

 and was equally mischievous, owing to its gTeat velocity and 

 consequent destructive energy. The sectional area of the 

 torrent at this place was between 4000 and 5000 feet, whilst 



L 



