52 Royal Society. 



gret. — Colonel Beaufoy may be considered an exception. That 

 gentleman is well known to have devoted his time and attention 

 to practical astronomy ; and having confined himself to certain 

 departments, in these he is said to have greatly excelled. His 

 observations of stars occulted by the moon, and of eclipses 

 of Jupiter's satellites, are believed to form the most complete 

 series any where to be found ; and such observations are very 

 essential for completing the theories of these respective bodies. 

 — And here it is not irrelevant to mention, that, by the libera- 

 lity of his son, (professionally engaged in other pursuits and in 

 other countries,) the instruments so well used by Col. Beaufoy 

 are now bestowed on the Astronomical Society. 



Two Fellows of the Society demand, however, our special 

 notice — The Rev. Abram Robertson, and The Rev. John 

 Hellins. 



Dr. Robertson first appeared in the town of Oxford as a 

 practitioner of medicine : but his abilities and mathematical 

 attainments soon attracted notice. He was induced to be- 

 come a member of the University ; was admitted into orders ; 

 received a chaplainship of Christ Church ; and became lec- 

 turer in geometry, first to the College, and afterwards to the 

 University. In due course Dr. Robertson became professor 

 of mathematics, and finally astronomer at the RadclifFe Ob- 

 servatory. We have in our Transactions various proofs of 

 Dr. Robertson's diligence and abilities. Two papers "On a 

 demonstration of the laws given by Sir Isaac Newton for ex- 

 panding a binomial." This expansion, justly esteemed of the 

 utmost importance as the foundation of every other, and as 

 developing the whole system of fluxions, has received various 

 elaborate demonstrations, the great author having simply con- 

 tented himself with the annunciation. Among those of the same 

 date none are more clear or satisfactory than the one given by 

 Dr. Robertson : nor does it detract from his merit, that sub- 

 sequently others have been devised in the general expansion of 

 functions, more concise, and perhaps more immediately urgent 

 of conviction on the mind. We have a third paper " On 

 the precession of the equinoxes." A fourth, showing " A di- 

 rect method of computing the excentric from the mean ano- 

 maly." And a fifth, demonstrating "A theorem in spherical 

 trigonometry, given by the late Dr. Maskelyne." But the 

 great work of Dr. Robertson is his Treatise on Conic Sec- 

 tions; — following the geometric method of Apollonius among 

 the ancients, and of Hamilton in our own times, by deriving 

 all the properties from the cone itself. As an academic book 

 for the instruction of young men this may well be stated as too 



extensive, 



