t 59 ] 


XVII. A Letter from Monfieur Wargentin* 
Secretary to the Royal Academy of Sciences 
in Sweden, to Mr, John Ellicott, F.R.S, 
relating to the late Tranft of Venus. 

Stockholm, December 24, 176.2* 

Read March 17, fTTl H E obfervations upon the laft 
I?63 ' X tranfit of Venus over the Sun 
made at the Cape of Good Hope are excellent, and 
feem to decide, that the horizontal parallax of the 
Sun is 8", 1 or 8", 3 at mod. I had before found 
it to be that quantity, from the obfervations made 
in Europe compared together; but the obfervations 
made at the Cape confirm it with the greateft evi¬ 
dence. 

It is of importance to be affured of the longitude 
of the places where the obfervations were made. I 
have endeavoured to determine them the beft I was 
able by obfervations of the eclipfes of Jupiter’s fatel¬ 
lites, made at the fame places. That you may the 
better judge, I thought proper to fend you all the 
obfervations of thefe fatellites made at different places 
the laft year. I defire you would communicate them 
to Mr. Mafon, and all thofe who intereft themfelves 
in the research of the parallax. It is pity that mef- 
fieurs L’Abbe Chappe, and Rumofki, did not fuc- 
ceed in obferving feveral eclipfes of the fatellites, at 
Tobielke and Selenginfk, the better to confirm the 
Longitudes of thofe places. However it appears to 
me, that the difference between the meridians of 

K 2 Green- 


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[ 6 ° ] 

Greenwich and Tobiefke is fcarcely more than 
4 h 32' 55". That between the meridians of Green¬ 
wich and Selenginfk, to judge from the three im- 
merfions obferved there, fhould be but 7 h 6' o, but 
from other confederations, I think it mull be 10 or 
15' more. If the longitude of thefe places fhould. 
be more exa&ly determined, I am perfuaded that we 
fhourd obtain the parallax of the Sun to nearly the 
tenth of a fecond, fo exa£t the obfervations made at 
Selenginfk and Tobiefke and the Cape appear to me. 

I fee you did not communicate to the Royal So¬ 
ciety all the obfervations made by Mr. Planman at 
Cajaneberg, they however deferve to be preferved. 
He oblerved 

h t tf 


The beginning of the entrance — at 3 59 56M 

Total immerfion of Venus or inte-i _ g. 

rior contact - -- -- -- -- i ■ 


Second interior contadl or beginning 

of the exit - - - -- 

Total emerfion--- 


] —10 7 59 

—-10 26 22 


Mr. Planman made ufe of a telefcope of 20 or 21 
feet; the latitude of Cajanebourg is 64° 13' 30''; 
the difference of meridians between Greenwich and 
Cajaneburg is fufBciently determined by obfervations 
upon the eelipfe of the Moon the 18th May 
1761, made at Stockholm and Cajaneburg. 

I have the honour to be with the greateft efteem, 
S I R, 

Your very humble and obedient fervant. 


P. Wargentin. 


2 


Eclipfes 






Eclipfes primi fatellitis Jovis, obfervatae Anno 1761: 
addito errore calculi pro quavis obfervatione, ut ap- 
pareat, quas fint prasftantiores. In calculo autem 
pofui differentiam meridianorum inter 


Obfervatorium Grenovic. et Parif. — 
Grenov. et Stockholm —- 
Grenov. et Upfolienfe —- 

Grenov. et Maflil.- 

Grenov. et Cap. B. Spei — 
Grenov. et InfuL Rodrig - 
Grenov. et Selenginlk — 
Grenov. et Cajaneburgh - 


0910 
1 12 o 
1 10 20 
O 21 19 
I *3 35 
4 12 5 Z 
7 6 15 
1 50 40 


Jan. 7. Em; 
June 13. Im. 

20. — 
July 22. — 


29. — 
A 3I ’ ~ 

Aug. 7. — 


14. — 


5 4 35 Stockholmias o 27 

14 37 47 Maffilis - — o 21* 

17 22 26 Cap.BonaeSpei a 31 

12 45 15 Paris o 7 

12 39 39 Grenov.--J- o 33 

16 48 55 Inf. Rodriga - -|~ o 9 

*4 3 8 35 Paris - - - - -J- o 33 

14 50 28 Maffilis---j- o 49 

15 42 44 Cap. B. Spei - -j- o 49 

13 10 29 Inf. Rodrig. - -J- o 56* 

10 51 52 Grenovic. - - 1 8* 

12 4 51 Stockholm, bona-|-o 9 

11 13 49 Maffilke - - - o 30 

12 5 46 Cap. B. Spei _ o 49 

J 3 59 39 Stockholm.certa.~j- o 10 

14 o 50 Cap. B. Sp. - -j- o 34 




[«* ] 


Aug. 21. Iro. 14 51 56 Paris - - ^ o 34 
15 56 2 Cap. B. Spei —|~ o 53 

23. —> 9 20 49 Paris - - - - -j- o 40 

10 22 42 Upfaliae - - - o 3* 

lo 25 10 Cap. B.Spei - - 4 - o 44 

23. 10 46 24 Seienginik - - 4 " 1 6 * 

28. — 16 48 41 Paris ----- o 12* 

30. — 11 758 Grenovici - - o 27 

12 17 43 Upfaliae — - 4 " 1 2 * 

12 21 32 Cap.B.Spei - 4- 0 28 

12 58 50 Cajaneburgi - o 15 

Sept. 1. — 9 49 40 Inf. Rodrig. - o 40 

8. *— 7 55 37 Maffiliae - — — o 17* 

9 23 40 Cajaneburgi - -j- 1 r* 

15 - “ 9 39 55 Pa ns - - - - - + o 5 

24. Em. 8 7 46 Grenovici - - -j- 1 1 

8 29 11 Maffiliae — - 4 " o 55 

9 21 35 Cap.B.Spei - -j-o 47 

Oft. 1. — 10 13 56 Paris — - 4 ” 0 59 

10. — 6 40 8 Paris - - - - 4 “ 0 45 

17. — 8 36 38 Paris — - - 4 -o 46 

Nov. 9. 8 5.1 19 Paris - - - - -j- 1 48* 

16. — 10 46 26 Paris — - - 4 “ 1 6 

18. — 5 27 40 Maffiliae- 4 * 0 3 2# 

Dec. 2. — 10 5 4 Stockholmiae - 4 " 0 3 2 * 

4. — 4 33 8 Stockholmiae - 4 " 0 39 

11. —• 6 25 44 Stockholmiae - 4 " 0 43 


Obfer- 





[ 63 ] 

Obfervafiones fecund! fetellitis, eodem anno habit©. 

h 

June 11. Im. 14 51 24 Cap. B. Spei —{- o 14 

18. — 17 27 11 Cap. B. Spei —o 4 

July 13. — 13 28 53 Paris 4 " 0 9 

20. —- 165 1 Paris — - - 4 “ o 35 

15 54 28 Grenovici - - 4 " 1 

17 9 42 Caput B. Spei 4 “ 0 J 9 

31. — 14 57 17 Selenginflc - - -f- 1 41* 

Aug. 7. — 10 30 9 Grenovici - - -f- o 59 

11 43 1 Stockh. optima 4 “ 0 7 

11 43 26 Cap. B. Spei —(- 1 17* 

14. — 14 21 37 Stockh. certa - 4 “ 0 l 7 

13 1839 Paris - - - - 4 -o 25 
25. —* 12 15 4 Selenginik - - 4 ~ o 9 

Sept. 1. — 916 Stockh. certa - —. o 5 

9 2 20 Cap. B. Spei - o 16 

8 59 19 Upiali® - « - -J- 1 2* 

8. — 10 37 59 Parifiis o 26 

10 29 30 Grenovici - - — o 5 

10 50 40 Mailili© - - - — o 6 

11 42 20 Cap. B. Spei. - ~y. o 30 

15. — 13 6 36 Grenovici - - 4, 3 12* 

Oft. 28. Em. 8 951 Mafiili© — - —. o 7 

Nov. ji. — 13 12 43 Paris - - - - — o 2 

22. — 5 18 12 Maflili©--j- o 49 

6 9 24 Stockh.dub. - 4 " 0 " 

Dec. 6. — 10 15 59 Paris - - - - 4 ^ 0 46 


Efclipies 



164 ] 

Eclipfes tertii fatdlitis Jovis, obfervatae anno 1761. 

h / // / // 
Maj. 11. Im. 15 19 3 Paris ----- 3 30 

Jun. 16. Em. 15 26 32 Cap. B. Spei — 221* 

23. Im. 15 20 6 Paris - - - - —- 5 20 

15 32 20 Maffiliae - --5 25 

15 10 24 Grenovici - - — 4 48 

Jol. 29. — 11 18 49 Paris---4 10* 

12 23 23 Stockh. certa - — 5 54 

12 24 o Cap. B. Spei — 5 8 

Em. 15 17 13 Cap. B. Spei o 23 

15 15 22 Stockh. certa - -j- ° 51 

Aug. 5.1m. 15 34 51 Paris--6 18 

Sept. 3. — 8 36 36 Cap. B. Spei - —- 5 25 

9 13 39 Cajaneburg-5 4 

10. — 11 27 6 Grenovici - - - 4 53 

11 49 9 Maffiliae-— 5 37 

Nov. 21. Em. 6 41 9 Paris - --o 15 

6 52 44 Maffiliae--j- o 51 

28. Im, 8 10 29 Paris--5 24 

8 23 31 Maffiliae — - — 6 18 

9 14 22 Stockh. optima — 6 28 

Em. 10 40 57 Paris - - --o 16 

i° 52 55 Maffiliae--— o 6 

11 44 34 Stockh. dub. - — 1 4* 


Ecfipfes 








[ 65 ] 


Eclipfcsquarti fatellitis, obfervatae Anno 1761; 


Aug. 10. Im. 
27. — 


Em. 


Nov. 2. Im: 
Em. 
19. Im. 


Em. 


* / // _ / // 

14 25 15 Parims - - - - -|- 2 18 

15 3 2 57 Cap. bonae Spei —- o 59 

8 41 40 Grenovici - ■* — o 21 

923 Maffiliae-o 35 

9 53 3 2 Ca P- B * s P ei - + 1 22 

9 50 18 Upfaliae - - - -}- 1 21 

10 16 23 Tornae-- 4 - 1 34 

11 47 41 Paris - - - - 4-3 10 

12 1 52 Maffiliae - - - 4 - 1 8* 

12 49 o Cap. B. Spei. —6 16 

12 48 7 Upfaliae - — 4 " 3 54 

12 47 31 Stockh. certa - 4 " o 10 

13 15 13 Tornae-(-3 6 

10 51 47 Maffiliae- \~ 5 5 ° 

12 57 37 Maffiliae —• - 4 “ 7 44 

6 6 34 Stockh.tub.max.— 8 51 

6 2 30 Ibid. tub. minore— 4 47 

4 57 16 Paris---2 23 

6 56 29 Paris --—6 32 


Obfervationes afterifco * notatae, minus certas fulpi- 
cor. Differentiae inter reliquas tribuendae videntur diffe- 
rentiis telefcopiorum, majori minorive aeris ferenitati, 
et fortaffis cuidam incertitudini circa differentias meri* 
dianorum. 

Obfervationes Stockholmenfes habitae funt telefcopio 
novo Dollondiano 10 ped. objefta I20 es fecundum di- 
ametros amplificante. 


Vox. LIII. 


L 


XVII. An 






