be employed. But Mr. Blundevile informs us that "the Spaniards doe
commonly make their astrolabes narrow and weighty, which for the most
part are not much above five inches broad, and yet doe weigh at the
least foure pound, & to that end the lower part is made a great deale
thicker than the upper part towards the ring or handle." _Vide
M. Blendeale his Exercises_, London, 1622, pp. 595, 597. This Spanish
instrument, it will be observed, is very similar to that found on the
Old Portage road, and the latter may have been of Spanish make.

In order to take the latitude in Champlain's day, at least three
distinct steps or processes were necessary, and the following
directions might have been given.

I. Let the astrolabe be suspended so that it shall hang plumb. Direct
the index or diopter to the sun at noon, so that the same ray of light
may shine through both holes in the two tablets or pinules on the
diopter, and the diopter will point to the degree of the sun's meridian
altitude indicated on the outer rim of the astrolabe.

II. Ascertain the exact degree of the sun's declination for that day,
by a table calculated for that purpose, which accompanies the
astrolabe.

III. Subtract the declination, so found, if it be northerly, from the
meridian altitude; or if the declination be southerly, add the
declination to the meridian altitude, and the result, subtracted from
90 deg., will give the latitude.

In these several processes of taking the latitude there are numerous
possibilities of inexactness. It does not appear that any correction