624

APPENDIX.

of a second of time. It is contemplated, in connexion with this improve-ment, to transmit Greenwich time, by means of the electric telegraph, toall the most important places in the kingdom. The realisation of thisproject will constitute a boon of inestimable value to the outports, byaffording on all occasions a reliable standard for the regulation of chro-nometers. The successful construction of the submarine telegraphbetween Dover and Calais will also enable the Royal Observatory torecord transits simultaneously with the Royal Observatory of Paris andother similar establishments on the Continent , by which means theirrespective longitudes relatively to each other may be more accuratelyascertained. The immense importance of this object must be obviousto any person who possesses an ordinary acquaintance with astronomicalscience.

VII.

Copy of the Note of the Observation of y Dbaconis, made byBradley, at Kew, with the zenith sector of Molyneux, on the 21st ofDecember, 1725 ; the discordance of which with the results of previousobservations, revealed to him, the first glimpse of his immortal discoveryof the Aberration of Light.

It has been mentioned at page 337 that the original note of the obser-vation, of which the subjoined words are an exact copy, was found a fewyears since by Prof. Rigaud, among the manuscripts of Bradley, writtenupon a loose piece of paper.

Dec 21 st Tuesday 5 h 40' sider timeAdjusted y e mark to y e Plumb line& then y e Index stood at 85 h 48' 22" y e star entred49 52| Star at y e Cross51 24 Star went outcould

As soon as I let go y e course

A

screw I perceived y e star toomuch to y e right hand &so it continued till it passedy e Cross thread and within a quarterwas

of a minute after it had passedgraduat

I turned y e fine screw till I saw

A

y e light of y e star perfectlybissected and after y e observation I found y e indexat Ilf, so that by thisobservation y emark is about 3"ftoo much southbut adjustingy e mark and plumb lineI found y e index at 8£.