=1749.= It is in the mathematical doctrine of Invariance, the realm wherein are sought and found configurations and types of being that, amidst the swirl and stress of countless hosts of transformations remain immutable, and the spirit dwells in contemplation of the serene and eternal reign of the subtile laws of Form, it is there that Theology may find, if she will, the clearest conceptions, the noblest symbols, the most inspiring intimations, the most illuminating illustrations, and the surest guarantees of the object of her teaching and her quest, an Eternal Being, unchanging in the midst of the universal flux. --KEYSER, C. J. _Lectures on Science, Philosophy and Art (New York, 1908), p. 42._ =1750.= I think that young chemists desirous of raising their science to its proper rank would act wisely in making themselves master betimes of the theory of algebraic forms. What mechanics is to physics, that I think is algebraic morphology, founded at option on the theory of partitions or ideal elements, or both, is destined to be to the chemistry of the future ... invariants and isomerism are sister theories.--SYLVESTER, J. J. _American Journal of Mathematics, Vol. 1 (1878), p. 126._ =1751.= The great notion of Group, ... though it had barely merged into consciousness a hundred years ago, has meanwhile become a concept of fundamental importance and prodigious fertility, not only affording the basis of an imposing doctrine--the Theory of Groups--but therewith serving also as a bond of union, a kind of connective tissue, or rather as an immense cerebro-spinal system, uniting together a large number of widely dissimilar doctrines as organs of a single body.--KEYSER, C. J. _Lectures on Science, Philosophy and Art (New York, 1908), p. 12._ =1752.= In recent times the view becomes more and more prevalent that many branches of mathematics are nothing but the theory of invariants of special groups.--LIE, SOPHUS. _Continuierliche Gruppen--Scheffers (Leipzig, 1893), p. 665._ =1753.= Universal Algebra has been looked on with some suspicion by many mathematicians, as being without intrinsic mathematical interest and as being comparatively useless as an engine of investigation.... But it may be shown that Universal Algebra has the same claim to be a serious subject of mathematical study as any other branch of mathematics.--WHITEHEAD, A. N. _Universal Algebra (Cambridge, 1898), Preface, p. vi._