444 TlMEHRI. 
filament of Carbon lasted — often iooo to 7000 hours ; and 
they could now be got to give from a single candle 
power, to 1000. The mechanical applications of electri- 
city were then touched upon, and it was pointed out how 
waterfalls and windmills could do good work in connec- 
tion with Storage Batteries, which were explained. 
The probable development of electric applications were 
referred to, showing that the ten million people, workers 
and their connections all the world over, in electricity 
generally, including electro-plating, welding, manufac- 
turing, &c, had a busy future before them. 
The leclure was illustrated by the various instru- 
ments referred to, and experiments performed in 
conneclion with the principle of the telegraph, the modes 
of electric lighting and the applications of electricity to 
mechanical work. Telegraphic communications were 
made with New Amsterdam, Leguan and Trinidad, and 
messages were sent and received. 
8. — "the utilisation of waste substances." 
Delivered on Thursday, December 2gth, by Luke M. Hill, Bac. Eng., 
Town Superintendent, Hon. Secretary to the Society. 
The first part of the lecture was devoted to the utilisa- 
tion of waste from mining operations and manufactures, 
which with the exception of gas, are carried on outside of 
the colony. Under this section of the lecture, the utilisa- 
tion of shale, slate debris, slag, alkali waste, coal tar and 
the various complex products obtained from it, were 
dealt with, the methods by which they were rendered of 
use and their importance being brought into prominence. 
The consideration of the utilisation of waste produced 
