In the course of the 19th century the idea that the different elements are constituted by different groupings or condensations of one primal matter - a speculation which, if proved to be well grounded, would imply the possibility of changing one element into another - found favour with more than one responsible chemist; but experimental research failed to yield any evidence that was generally regarded as offering any support to this hypothesis.
A larger and more important series of condensations may be grouped together as resulting from the elimination of the elements of water between carbonyl (CO) and methylene (CH 2) groups.
Kane; methylethyl ketone and methyl-n-propyl ketone suffer similar condensations to s-triethylbenzene and s-tri-n-propylbenzene respectively.
Somewhat similar condensations are: of geranial or citral, (CH 3) 2 CH CH 2 CH :CH C(CH 3) :CH CHO, to p-isopropylmethylbenzene or cymene; of the condensation product of methylethylacrolein and acetone, CH3 CH2 CH:C(CH3) CH:CH CO CH3, to [1.3.
As a useful preliminary it is convenient to divide heterocyclic ring systems into two leading groups: (I) systems resulting from simple internal dehydration (or similar condensations) of saturated aliphatic compounds - such compounds are: the internal anhydrides or cyclic ethers of the glycols and thioglycols (ethylene oxide, &c.); the cyclic alkyleneimides resulting from the splitting off of ammonia between the amino groups of diaminoparaffins (pyrrolidine, piperazine, &c.); the cyclic esters of oxycarboxylic acids (lactones, lactides); the internal anhydrides of aminocarboxylic acids (lactams, betaines); cyclic derivatives of dicarboxylic acids (anhydrides, imides, alkylen-esters, alkylenamides, &c.).
Such condensations were especially studied by M.
Similar condensations produced the sun and stars; and the flaming state of these bodies is due to the velocity of their motions.
The philosophical works, occupying the first six and the last of the twenty-one volumes, are generally divided according to the Aristotelian scheme of the sciences, and consist of interpretations and condensations of Aristotle's relative works, with supplementary discussions depending on the questions then agitated, and occasionally divergences from the opinions of the master.
The cycle of its transformations and successive condensations constitutes the life of the universe, the mode of existence proper to finite and particular being.
97 Ursae majoris is of the planetary type; the earl of Rosse observed two spiral condensations turning in opposite directions, - hence its name, - the " Owl nebula."