AUCKLAND INSTITUTE.

New Zealand Herald, Volume XXV, Issue 9108, 17 July 1888, Page 5

AUCKLAND INSTITUTE.

LECTURE BY PROFESSOR BROWN. There< was an .unusually large' attendance last night at the Auckland Institute to hear Professor Brown's promised lecture on " Electrolysis." Professor Thomas presided, r

Professor Brown began by saying that they all knew something of what was meant by the electric current, that it travelled along wires and other solid substances. It was not, however, with the passage of L electric currents through solids that he had to deal -with " that night, but its passage through liquids, a subject which, although less known, was fully as important. Unlike solids liquids were altered by the passage of the electric current, and it was about the changes produced in these he had to speak/ He drew attention to a galvanic battery which was connected by a coiled wire with a galvanometer, the needle of which was deflected by the ' slightest electric current. This instrument, Professor Brown, explained, was constructed in the laboratory of the Auckland University, and embraced all the newest improvements. A series of highly interesting experiments which were then made illustrating the different conducting capacity, of mercury, alcohol, solutions of "salts, etc. By means of the Oxyhydrogen lamp the professor illustrated the decomposition by the electric current, of sugar of lead, and explained that nearly all salts when in a liquid state behaved in the same manner, the metal being separated. This was the foundation of electro-plating. After some further experiments he passed'to the application of electrolysis to secondary and primary battery, and promised to deal with this phase of the question when he obtained the secondary batteries which were ordered by the Council of the University. Touching on the application of electrolysis to a stamp battery for gold saving, he showed a piece ot silvered copper plate, such as those in ordinary use. He explained how quicksilver became sickened,and illustrated it by depositing a sulphur film on the plate which quite darkened its surface, but when the elecric current was applied the scum disappeared, and the shining surface showed all its glittering brightness. Yet he said this simple method was not applied at the stamp batteries simply because people did not know how to apply it. Electrolysis would, however, play a, great part in the pan process, which would play a great part on the Thames. He also drew attention to two other applications of electrolysis. One was its sanitary use m the purification of sewage, a method of whicn had been invented, arid was carried out successfully- at Barking, one of the outlets of London sewage. He also referred to its use in surgery and medical science generally, ana said the electric current was found to possess a peculiar action on many growths, such as tumors, and the passage of the current arrested their development. ■ . At the conclusion of his address, 1 rofessor Brown was accorded a hearty vote of thanks bv acclamation. Professor Thomas announced that the next meeting of the Institute would be held on the 30th instant. ' • .