PHYSICAL AND MATHEMATICAL SCIENCES. Set)

history of physical science. It has bee'n well remarked,that mathematicians had found out the area of the circle,and calculated its circumference to a hundred places ofdecimals, before artists had divided an arc into minutes;and that many excellent treatises had been written onthe properties of curves before a straight line had beendrawn of any considerable length, or measured withany tolerable exactness, on the surface of the globe.*

The first attempt to renew such measures in moderntimes, was that of Snell, professor of mathematics atLeyden (already mentioned as the discoverer of the greatlaw of refraction!, described in a work called “ Era-tosthenes Batavus,” 1617- The operations were carriedon hy a series of triangles, and the result, after the cor-rection of some errors, has been found to differ butlittle from subsequent measures.

Another attempt was made by Norwood in 16’35.He had observed the differences of latitude of Londonand York, and then measured the distance, though in asingularly rough manner, by measuring along the highroad : “ Sometimes,” he says, “ I measured, sometimesI paced; and I believe I am within a scantling of thetruth.” This affords a characteristic record of the in-fancy of observation.

Fernel , a French physician , soon after measured, witha similar object, the distance from Paris to Amiens , bymeans of the revolutions of a wheel; they lie nearlyunder the same meridian, and his resulting length of adegree was not far short of the truth.

But investigations like these, it must be evident, couldnot satisfy the increasing demands of science. TheFrench Academy of Sciences became interested in thequestion, hud an elaborate measurement was under-taken under its auspices, by the abbe Picard, whichafforded the first result on which any reliance could beplaced.

All these measurements had been employed as fur-nishing the data for determining the magnitude of the

* Ellin. Review, v. 391.