pigafetta’ s voyage round the world. 383

fame meridian, or making fome known angle with it. In the prefent day it is ufual toobferve the ftar y of Caffiopea, which is called the Girdle *, and is nearly under thefame meridian. In the time of Pigafetta they obferved the relation the polar ftar boreto the ftars and y of the Letter Bear, which form a triangle with the polar ftar andthe pole. After which they fattened a triangular rule on the centre, or pole, of thea ftrolabe, by the obtufe angle on which it turned f. Even now a rule nearly fimilar isufed, and the inftrument ufed for this purpofe is called nodlurlabe J. But, ■ fpite of thedifferent pofition and diftance of the ftars, and notwithstanding the inftruments ufed inthe prefent day are diffimilar to thofe'at that time adopted, it is vifible that the method°f afc'ertaining the latitude by the height of the pole at night, and of the fun by day,a re (till the fame ; and thefe methods it is that our author teaches for finding the lati-tude at fea.

With refpedl to the afcertainment of the longitude, Meflieurs de la Lande andBougainville conceive the method by taking the horary angles of the moon is the fafefta nd mod convenient § ; and Triefneker ||, with Bouguer ^[, affirm, that the beft methodls by the conjunction with, and eclipfes of the ftars by the moon. Our author recom-mends the fame in the two firft of the three methods he gives for this purpofe. Andas he fails to fpeak of the mode of finding the longitude by folar eclipfes, it is evidentthat with this he was unacquainted, and confequently that he did not fee Magellan prac-free it at the river of Sta. Cruz, as Caftagneda affirms **.

I am aware that all the obfervations made were computed upon the almanacks of theand that thefe almanacks were far from calculating with that precifion which isadmired in the ephemerides of the prefent time the different phenomena of the hea-v ens : I know that the lunar tables were then much lefs perfefl: than they now are, andthat Pigafetta had not the advantage of being enabled, as the telefcope had not yet beenmvented, toobferve the eclipfes of the fatellites of Jupiter. All refults then refted on°bfervations made with very imperfefl: inftruments, and efpecially the aftrolabe, of whichpigafetta often fpeaks, the meteorofeope, the torquetum, the backftaff, and the univerfalc hcle, inftruments and machines which were neither certain in their refults nor eafy orc °mmodious to ufe, as are now the fextant of Hadley, the Englilh quadrant, the circle

Borda, and other inftruments fo formed that the motion of the veffel is no impedi-ment to their being ufed, nor capable of affefting their exaftitude. The correftitefs ofthe refult of obfervations for determining the longitude neceflarily depends on the pre-G] fenefs of the time at which the obfervations are made, and the relation it bears to that°f the country the longitude of which is known, or fuppofed to be known : at thatPeriod the only means of determining the hour was by the fand glafs, in the conftruc-tlQ n and ufe of which it is impoffible to be exaCt, fo that indeed Pigafetta himfelf didrely ort. it. But at prefent we have excellent chronometers and fea-watches,"mich are not liable to any variation, or which, if they experience any, are readily cor-^(fted. By means of thefe it is that we obtain that precifion of time which allows ofbe longitudinal diftance being afeertained with the. utmoft exaftitude, a matter as diffi-cult u ntil this invention as it was material for navigators ; and for the difeovery of

* "p

. Traite de Navigation-

* uefe machines are to be feen in Apiano.

Aftronomicum Caefareum

and in Lucini. Arcano del

$ Didlionnaire de la Marine, artic. Nocturlabe , where the figure of tins inftrument is gwen.§ Bougainville Voyage, tome xi. p- 65-II Allgemtine Geogr. Ephem. Jan. 179°*

U Traite de Navigation.

** Page xxxix. note ii.

which