rigaeetta’s voyage round the world.

39 °

in this circle in fuch manner that a line from one to the other may cut the centre, andat fun-rife turn this circle in fuch manner that the pins may be in a line with thecentre of the fun; at the inftant the fun fets repeat the fame operation. By thismeans you will find the declination of the fun from the equinoctial line, whethernorthward or fouthward. When you have determined the angle at which the funrifes and fets from the equinoctial line,' you obtain the mean diftance, which is themeridional line; and you will thus fee how much the needle north-eafts or north-wefts :by the degrees of deviation of the needle you will know your longitude from the For-tunate iflands, that is to fay, from Teneriffe, whether eaftward or weftward. Thismethod has the fanction of experience

On Steering the Ship.

“ Would you navigate to any country, it is firft requifite you fhould know its geo*graphical pofition, that is to fay its latitude and longitude. After which, by the help ofthe compafs you will fleer direCUy towards it. And as the needle north-eafts or north-wefts, its deviation muft be found by the means I have prefcribed; then fubtraft or addwhat is neceffary to the compafs in order that the prow of the fhip, regulated by thecompafs, may conftantly point in the direction required.

“ If unfortunately the compafs fhould be loft, or if its real deviation from the meri-dional line fhould be unknown, the pilot muft regulate himfelf by the fun at noon.When the meridian is fo fixed that it cuts direClly acrofs the veflel its prow may bedirefted any way at pleafure. For example; fuppofing the pilot would fleer fromnorth-eaft to fouth-weft, turn the compafs in fuch manner that the veflel may have•its prow towards the weft and its poop towards the eaft; then on the circle of thewinds, divided into three hundred and fixty degrees, or four times ninety, fix two pins*one at forty-five degrees from the eaft and the north, the other at equal diftance fromthe weft and fouth; turn then the helm fo that the two pins may be on the meridian,and the prow will point whither the veflel is to fleer t provided the pins fhould not beon the true meridional line, the courfe will be a falfe one, and muft be reClified.When the veflel makes the land the truth of what I fay will appear.

“ By means of an aftrolabe compofed of plates f, the meridional line may readilybe found, as well as the poles and the equinoClial line by obfervation of the fun byday, and at night of the moon and ftars. For thefe laft, inftead of the verghezitatwo finall flicks muft be placed in the middle of the aftrolabe, through which the ftarmay be obferved.”

After thus defcribing the method of giving the direClion wifhed for to the vefleljPigafetta proceeds to teach the means of determining the point of the compafs towhich the veflel in failing from one part to another fhould fleer. In order to makehimfelf the better underftood he adduces feveral examples. “ Are you defirous,’fays he, “ of going from fouth to north, or from north to fouth, under the fame lon-gitude, keep conftantly on the fame meridional line. Would you fail from eaft t0

* I have already obferved that in the time of Pigafetta the needle at the Canaries was nearly on themagnetic equator; and it muft further be obferved that chance has carried navigators into certainparts where the degrees of declination torrefponded with the degrees of longitude from the ifland ofTeneriffe.

f We have aftrolabes made of different kinds of plates, the largeft for fake of lightnefs being of paft e ”Foard ; the others are of brafs or copper.

t This probably us the fame thing with the mediclino. See Note, page 389. _

8 Wefts