Page:Proceedings of the Royal Society of London Vol 4.djvu/223

Rh Position geographique des principaux points de la Triangulation des

Calif or nies et des cotes de V Ocean Pacifique du Mexique par Je Comte Vincent Piccolomini.

Volianos de las Virgenes

Cap S. Lucas (Basse californie) •

Monterrey (Haute californie)

Guaymas (Departenient de Sonora)

Matamoros (Texas)

Id. Id. Barra grande de S. Yayo

Id. Id. Barra del Rio

Bejar (Texas)

Mine d'or de S. Yago de los Caballeros

Vulians de Tuxtla

Namampateptl (Province de Vera Cruz)

Bahia de San Francesco (au cap los Key ex dan;

la haute Californie)

Port de San Bias, totu: de I'eglise (guadalajara) Volcanos de Colima

29 91 14-35 23 08 35-27 36- 58 17-85 27 55 00-48 ;ill

25 59 22-07 j 9

26 30 27-15 25 53 03-11 29 74 88-93 25 13 77-04 IS 47 25-91 19 21 48-71

37 59 17-29 21 67 05-54 19 03 45-17

N.B. L'instmment employe pour determiner les Longitudes etait un Chronometre de O. H. Bestor ; pour la mesure des triangles de premier ordre je me servis d'un theodolite de dix pouces de diametre sortant des ateliers de Munchi, pourvu de quatre verniers et don- nant 10". Les elevations du sol furent determinees par des obser- vations barometriques faites avec soin, souvent repetees et deduites par le moyen d'observations correspondants ; eUes furent calculees d'apres la methode d'Oltmanns et verifiees par celles du Baron Zach, — Y.P.

Report on the co-operation of the Russian and German ob- servers, in a system of simultaneous INIagnetical Observations." By the Rev. H. Lloyd, F.R.S., in a letter addressed to Sir John F. W. Herschel, Bart., V.P.R.S. Communicated by Sir John Her- schel.

" On Magnetical Observations in Germany, Norway, and Russia." By Major Sabine, R.A., V.P.R.S., in a letter to Baron von Hum- boldt, For. Mem. R.S., dated Oct. 24th, 1839.

These letters relate to communications which Professor Lloyd and Major Sabine have had, conformably to a resolution of the Council of the Royal Society, with the scientific authorities at Got- tingen, Berlin, and St. Petersburg, respecting the organization of a simultaneous system of magnetical observations. It appears, from these letters, that the system proposed by the Royal Society is viewed with general interest and approbation ; and nineteen stations are enumerated at which there is reason to expect that magnetical observatories, acting in concert, on that system, will be established.