The second includes a "Method for the Quadrature of Parabolas," and a treatise "on Maxima and Minima, on Tangents, and on Centres of Gravity," containing the same solutions of a variety of problems as were afterwards incorporated into the more extensive method of fluxions by Newton and Leibnitz.
The fifth book contains properties of normals and their envelopes, thus embracing the germs of the theory of evolutes, and also maxima and minima problems, such as to draw the longest and shortest lines from a given point to a conic; the sixth book is concerned with the similarity of conics; the seventh with complementary chords and conjugate diameters; the eighth book, according to the restoration of Edmund Halley, continues the subject of the preceding book.
The canyon of the Patia through the Western Cordillera is known as the "Minima gorge," and has been cut to a depth of 1676 ft., above which the perpendicular mountain sides rise like a wall some thousands of feet more.
At one point in its course it is crossed by the Rumichaca arch, a natural arch of stone, popularly known as the "Inca's bridge," which with the Minima gorge should be classed among the natural wonders of the world.
As to minima within the period, the lowest totals for British possessions were: imports £91,851,534 in 1893, and exports, the figure quoted for 1895; for foreign countries, imports £312,836,644 in 1893, and exports £195,133,239 in 1894; grand totals, imports £ 4 0 4, 688,178 in 1893, and exports £273,785,867 in 1894.