[ 347 J 
XLVII—ON THE EQUATORIAL TELESCOPE AND ON 
THE NEW OBSERVATORY OF THE QUEEN’S COLLEGE, 
CORK, sy HOWARD GRUBB, .z., F.p.a.s. Paves 24 and 
25, AND Woovcuts. 
[Read April 21st, 1879. ] 
Part I, 
PE OU ATOR PAL. 
Kquatorial telescope mountings have undergone considerable 
modifications and improvements within the last ten years. 
These modifications and improvements represent to a large 
extent the efforts of the optician to keep pace with the modified 
ideas of astronomical observers; for, while the old idea of render- 
ing an equatorial an instrument of precision is pretty nearly 
exploded, the numerous branches of research into which Physical 
Astronomy can now be divided, have, while increasing the num- 
ber of its votaries, also increased the demand for instruments 
more comprehensive in their character, and in which the labour 
of manipulation may be reduced to a minimum. Hence the 
demand of the astronomers for “ labour saving ” contrivances, and 
I propose in this paper to bring forward some of the various con- 
trivances and modifications which I have introduced for this 
purpose. In the first instance, I would direct attention to the 
general form of the instrument. It will be seen that in this 
respect I have endeavoured to steer a middle course between two 
extremes, for, while in some instances, the centre of motion of 
the instrument, 7.¢., the point at which the polar and declination 
axes cross (D) is placed over the centre of the pier, and thus the 
instrument has almost always to be reversed when it reaches the 
meridian (as the telescope tube comes into contact with the 
mounting immediately at, or a very little beyond that position), 
in other forms the polar pillar, as I call it, P. (that is, the pillar 
in which the polar axis revolves), is prolonged until it reaches 
through the floor, the framework and stay (S) being dispensed 
