MENSURATION. The art of measuring lines, superficies, and solids, which, in Trance of its extensive application to the pur poses of life, is considered as of the greatest.; importance Foetid treats of mensuration, as the as re. gards surfaces, only of the m •mg of trian gles; and in regaid to curvilinear figure, he attempted the measurement of the circle and the sphere. Archimedes carried this subject to a much greater extent : he found the area of a parabola to be two thirds of its chann scaling triangle, which, with the exception oldie hinnies of Hippocrates, was the first in stance of the quadrature of a curvilinear space. He likewise determined the ratio of spheroids and conaids to their circumscribing cylinders,' and bas left us his attempt at the qoadrature of the circle. He dernotketrated that the area of a circle is equal to the area of a right-angled triangle, of which one of its sides about the right an is equal to the radius, and the otba to the circumference ; and thus reduced the quadrature tif the circle to the determining the ratio of the circumference to the diameter, a problem, in the solution of which he could only arrive at an approximation to the truth, showing that the ratio between the circumfe rence and the diameter was less than that of 7 to 22. What A rc.himedes failed to effect in
this rnspoa has continued to this day mat notwithstanding the efforts which have been made by subsequent mathematicians, particularly within the last three centuries, to arrive at a greater approximation. As all hopes of accurately squarmg the circle and some other asses were at length given up, mathematicians applied themselves to the find ing most convenient series for approxi mating towards their true lengths and quadra tures ; and the science of mensuration has in consequence assumed a more consistent form, as may to clearly seen in the treatises of Hawney, Robertson, Hutton, and Bonnycaelle AlEPHITIC. Poisonous, like the Mephitis, or Damp, as it is called by the minus; as Mephitic Air, another name for nitrogen gas, on accoent of its noxious quality: and Me phitic Acid, carbonic acid, so caned because it cannot be respired without causing death.