el 
IX. 
NOTE ON THE RESULTS THAT MAY BE EXPECTED FROM 
THE PROPOSED MONSTER TELESCOPE OF THE PARIS 
EXHIBITION OF 1900. By SIR HOWARD GRUBB, F.B.S5., 
Vice-President, R.D.S. 
(ABSTRACT.) 
[Read January 18; Received for Publication Marcu 15; 
Published Aprit 22, 1899.] 
Tue Author stated that so many exaggerated reports had appeared 
lately in the newspapers as to the wonderful results expected 
from the great refracting telescope proposed for the 1900 Paris 
Exhibition, that he thought it might interest the Royal Dublin 
Society to know what might reasonably be expected from such an 
instrument. 
According to some papers the Moon is to be brought within 
four miles of the Earth; while in one account, purporting to be 
extracted from the Morning Post, this telescope was to be capable 
of taking photographs of celestial objects on a scale 10,000 times 
larger than would be possible by any existing telescope. 
After describing the general features of the proposed Paris 
telescope, showing how the light-collecting power and magnifying 
power of telescopes can be estimated, and why it is possible to use 
high powers with larger apertures &c., the author showed that the 
light-collecting power of this Paris telescope was only about 50 per 
cent. greater than that of the 40-inch refractor of the Yerkes Obser- 
vatory, Chicago, or more strictly speaking, 39 per cent., allowance 
being made for the light lost by the reflector. In magnifying 
power, or power of bringing objects apparently closer, it only 
exceeded the “ Yerkes” instrument by 20 per cent., while in both 
respects it fell far below the reflecting instrument of Lord Rosse 
erected more than half a century ago. 
