358 THE ROYAL SOCIETY OF VICTORIA. 



it sng'g'ests at once that scientific progress in the treatment of disease will come 

 but slowly, until natural philosophy and chemistry, especially in its dynamical 

 aspect, form as large a part of a medical student's training as even anatomy itself, 

 Mr. Rusden's paper " On the Ethics of Opinion," was read at the September 

 meeting ; it treated of how far men are properly liable to blame or praise, reward 

 or punishment, for their thoughts or actions. The novelty of character of this . 

 contribution may have given rise to an impression that it was not exactly of a 

 nature included within the olijects of the society ; very little consideration must, 

 however, show that any attempt to contribute to social improvement, so long as 

 it is regarded in its scientific aspect, may be fairly considered to gome within the 

 scope of this society. 



" The Danger of Collision between Vessels crossing one another's Tracks," 

 was the title of a communication from Captain Peny, read to you at the Novem- 

 ber meeting. In thts paper a very simple method of procedure to be adopted by 

 approaching vessels was suggested by the writer, by which danger of collision 

 might, in nearly all cases, be avoided. The plan suggested consists in the 

 approaching ships ascertaining' if the same relative bearings between them con- 

 tinues to be maintained, and if so, to alter their course ; for, as was demonstrated 

 by a simple diagram, collision becomes inevitable if the same bearing is main- 

 tained. So simple a mode of even lessening the probability of collisions, if not 

 already generally adopted by nautical men, should be well noted. 



At the same meeting a paper " On the Purification of Water," was presented by 

 Mr. Dahlke. This related to a method of filtration devised by the writer, by 

 which organic and most mineral impurities, including the salts of lead, were 

 removed from drinking water ; brackislmess, also, by a judicious arrangement 

 of this filtering medium, he stated might be removed to a considerable extent. 

 He exhibited a filter that he had constnicted which was partly tested in your 

 presence; the further testing of its properties you will remember was referred to 

 Mr. Newbery, who reported at the next meeting that the filter not only did all that 

 Mr. Dalhke had stated, but he found it to possess powers of filtration beyond 

 anything he had previously known ; he had tried it very severely hy filtering 

 solutions of salt, sulphate of magnesia, and, even sulphate of ammonii'nn with it, 

 and in every case the filtrate passed out as drinkable water, with barely traces 

 of the substance previously in solution. Passing h(>t water in a reverse way 

 through the filter removed the suspended salts and restored the activity of the 

 filtering medium, Avhich, after continued use, was diminished. 



Some experiments were since tiied on the filtration of sea-water by Mr. Dahlke, 

 and I believe he is now engaged in the constnrction of a large filter for rendering 

 brackish water fit for sheep and cattle at some station on the Darling river. There 

 is no doubt that the kind of filter exhibited is exceedingly succesfnl as an ordi- 

 nary domestic filter, but whether it will become practically successful in so remar- 

 kable a use as that of removina- salt from sea or very brackish watere is not vet 

 demonstrated. 



I congratulate you upon these residts of your past session, and I regard them 

 as an evidence of increasing activity and an earnest of advancement in the olyects 

 of this society. 



You will be glad to learn that our intercourse with kindred societies has 

 increased ; thereare now 86 learned bodies with which we are in communication 

 and interchange of publications; 41. of these are Ijritish, 36 continental Euro- 

 pean, 5 American, 2 Asiatic, and 5 colonial. Our librar}- has been consideralily 

 increased l)y donations from these societies, and a coni})lete catalogue, compiled 

 by your honorary librarian. Dr. Neilcl, is appended to the second part of the last 

 volume of our transactions. 



I would now revert to the year's history and present state of oiu- public scien- 

 tific departments, and in doing so, if I speak at more length of matters concerning 

 our observatory than of the other institutions, it is only because I am better acquain- 

 ted with the details of its progress. 



