ALSTED (John-Henry)

, a German protestant divine, and one of the most indefatigable writers of the 17th century. He was some time professor of philosophy and divinity at Herborn in the county of Nassau: from thence he went into Transilvania, to be professor at Alba Julia; where he continued till his death, which happened in 1638, being then 50 years of age. He applied himself chiefly to compose methods, and to reduce the several branches of arts and sciences into systems. His Encyclopædia has been much esteemed even by Roman Catholics; it was printed at Lyons, and sold very well throughout all France. Vossius mentions the Encyclopædia in general, but speaks of his treatise of Arithmetic more particularly, and allows the author to have been a man of great reading and universal erudition. His Thesaurus Chronologicus is by some esteemed one of his best works, and has gone through several editions, though others speak of it with contempt. In his Triumphus Biblicus Alsted endeavours to prove that the materials and principles of all the arts and sciences may be found in the scriptures; but he gained very few to his opinion. John Himmelius wrote a piece against his Theologia Polemica, which was one of Alsted's best performances. It seems he was a millenarian, having published, in 1672, a treatise De Mille Annis, in which he asserts that the faithful shall reign with Jesus Christ upon earth a thousand years; after which will be the general resurrection, and the last judgment; and he pretended that this reign would commence in the year 1694.

ALTERNATE angles, are the internal angles, A and B, or a and b, made by a line cutting two parallel lines, and lying on opposite sides of the cutting line. It is the property of these angles to be always equal to each other, namely the angle A = the angle B, and the angle a = the angle b. And the exterior alternate angles are also equal.

Alternate Ratio or Proportion, is the ratio of the one antecedent to the other, or of one consequent to the other, in any proportion, in which the quantities are of the same kind. So if A : B :: C : D, then alternately, or by alternation A : C :: B : D.