140 Proceedings of the Royal Society of Victoria. 



in India, and the pendulums were now swung in vacuo at 

 home. They were quite up to the modern form, being, in 

 fact, tlie last pendulums that had been made. They were 

 made on the most approved principles for the Indian Survey 

 in 1<S76 or 1877. He did not think any pendulums had 

 been made since, except one or two experimental ones in 

 Germany. With regard to taking them down to the South- 

 ern regions, they could be easily carried if a place could be 

 obtained to swing them in, and if an Expedition were carried 

 out, it would be very desirable tliat one of the pendulums 

 should go with it. 



The President remarked that all the instruments needed 

 for such gravity determinations would be a pendulum with 

 all its subsidiary apparatus, a clock, and a transit instrument 

 for regulating the clock. 



Mr. Ellery said it might be done with chronometers, but 

 he did not think that the pendulum could be so weh swung 

 with the chronometer as with the clock. Of course it was 

 a sine qua non that to get good pendulum results, the 

 observer must be well trained, and have had a lot of actual 

 experience. 



The President suggested that such experience could be 

 obtained by one practising in Melbourne until thoroughly 

 acquainted with the work. At liow many places was it 

 proposed to swing the pendulum ? 



Mr. Ellery thought they should be swung in two or 

 three places at least, and that in fact it would be hardly 

 worth while getting them out unless they were swung in 

 four places. There was no necessity to swing them in a 

 great number of places. 



The President : What about sea coast versus inland ? 



Mr. Ellery said that, if experiments were made in that 

 way, the observations might be multiplied. The most 

 interesting experiment would be to repeat the observations 

 formerly made in Melbourne and Sydney, and in the interior 

 jDlains as distant from mountains as possible. 



Mr. White said the Overland Telegraph line would 

 facilitate the matter. The exact time also could be con- 

 veyed along the line direct from the Observatory. 



Professor Masson wished to know where the money was 

 to come from. 



