128 Mr. Farci/s Suggestions^ as to 



appropriating his labours to themselves, some of them: — but i 

 must restrain for the present my feehngs on tliis unpleasant sub- 

 ject, aiul with the hope ot drawing the attention of your scien- 

 tific Correspondents to the subject of the Nation;il Trigonome- 

 trical Siuvey, I vvill beg to transcribe a Letter, which in the last 

 Spring I addressed to a public Man, whose useful labours have 

 laid our country under lasting obligations to him: viz. 



" Man-h •16, 1816. 

 *' Sir, — I am very greatly obliged by your letter of yesterday, 

 and in consequence of the information (new to me), as to the 

 intended ex])eriments on a Pendulum, at the principal Trigo- 

 nomelrknl Sfaticms, beg permission, without delay, to offer to 

 the consideration of your very active and superior mind, a few 

 suggestions connected with this subject. 



" First, I would beg to recommend, that the Ln?idon {)cn- 

 dulum ob-^ervation should be made, on the floor of St. Paul's 

 Cathedral, or of St. Faith's church under it, exactly under the 

 Cross above the dome, which is a most popular and well settled 

 point in the Trig. Survey, and it will be very desirable, that si- 

 milar observations be made, as near as possible to (E or W of), 

 the Transit Instrument in Greenwich Observatory; and that 

 progressivelv, these pendulum observations should be made, at 

 everv, or at mainj, and those greatly distributed, Trig. Stations. 



" Second, That l)y the accurate and ready means which Ike 

 Ca?ials now furnish, and levellings for such, which have been 

 accurately made and recorded, when collected, examined and 

 compared, and by other cross levellings from these Canals to the 

 Sea (none of which would nov/ require to be very long), to as- 

 certain the Elevation of each Trig. Station, much more accu- 

 rately and satisfactorily than has yet been done. 



" Third, I am extremely desirous, for the interest of Science 

 and the honour of our Age, that every possible precision should 

 be given to our Trig. Survey, l)V employing (at the same time 

 with the pendulum) the capital Zenith Sector, which the nation 

 has purchased, and has long and often, I believe, lain unemployed 

 in the Tower, in settling the Latitudes, from actual observations; 

 so often and carefully repeated, on the Stars, at each Trig. Sta- 

 tion (and if confirmed by Pole-star observations the better), as 

 to leave no reiuriining doubts, on this very important head. 



" Doubtless, sir, you are acquainted with the al)le calcula- 

 tions and statements of doubts hereoii, in the Piiil. Trans. I)y 

 Don Rodrigue, a few years ago; and perhaps also, with the 

 virulent and improper attack on the Roy. Soc. for admitting the 

 Don's paper, and the refusals given, to repeat observations, or 

 otherwise^ by a proper defeuccj lo remove these doubts, by . a 



person. 



