192 SECTION PHYSICS. 



much felt near the end of the last century, about 1770, and the Univer- 

 sity not being able to furnish anything, the Radcliffe Trustees under- 

 took it and built that magnificent erection with which most of you are 

 no doubt familiar. But the instruments were servilely copied from 

 those at Greenwich, which was a very great misfortune for astronomy. 

 Here was an opportunity for bettering a very bad class of instrument 

 which had been used for the determination of the absolute places of 

 bodies, by a due consideration of what could be done in this new ob- 

 servatory ; but unfortunately Bird, who at that time was a great instru- 

 ment maker, had a reputation for his quadrants, and two quadrants 

 were ordered ; and a transit instrument of the character usual in those 

 days, with a small object glass, was also furnished, and that was the 

 equipment of the Observatory. It was thought by Dr. Robertson that 

 some instrument for observing casual phenomena would also be de- 

 sirable, and Sir William Herschel gave a good deal of consideration 

 to it, and recommended him to have this Newtonian reflecting tele- 

 scope. It is very similar to the one you see here on the table. It has 

 a small mirror of eight and a half inches, which was not considered 

 small then, and the focal length is ten feet. The epoch at which this 

 telescope was given is an important one and an interesting one. The 

 first mural circle had just been established at Greenwich, and then 

 began that series of observations which have only been improved upon 

 very recently, and which totally superseded all observations of zenith- 

 distances of bodies which before had been obtained by the quadrant. 

 You may consider that as an epoch in the new astronomy. The 

 Radcliffe Observer did not for a long time get any new instruments ; he 

 had not the power, in fact, of getting out of the groove in which things 

 then were. The quadrants continued in use up to almost the termina- 

 tion of the Directorship of Professor Rigaud, and it was only just 

 before the time when Mr. Johnson became Radcliffe Observer that a 

 meridian circle, based on that of Dr. Robinson of Armagh, was 

 established, and this you may consider another epoch in the astro- 

 nomy of the age. From this time began an uninterrupted series of 

 star-observations, rivalling those of Greenwich in the continuity and 

 the value of the definite series of observations which were made. 

 Similar observations have been kept up to the present time. 

 These things may not seem to have much connexion with the par- 



