135 



SCIENTIFIC SIDE-LIGHTS 



Coordination 

 Correspondence 



choose to exert ourselves, we can always 

 keep our illusions in a nascent or imper- 

 fectly developed stage. SULLY Illusions, ch. 

 6, p. 124. (A., 1897.) 



667. CORRELATION OF GROWTH 



The Law of Symmetry Plants, Animals, 

 and Crystals Symmetrical. One relation 

 which we detect in all variations of organic 

 growth is simply the relation of symmetry. 

 This kind and degree of correlation of 

 growth prevails even in the world which we 

 call inorganic. The corresponding sides and 

 angles of a crystal, for example, may be 

 said to be correlated together. The nature 

 of this relation is geometrical and numeric- 

 al. It is a relation having reference to in- 

 variable rules of number. As regards its 

 physical cause, all we can say is that it is 

 the result of forces whose property it is to 

 aggregate the particles of matter in definite 

 forms, which forms are symmetrical that 

 is to say, they are forms having an axis with 

 equal developments on either side. Correla- 

 tion of growth, therefore, in this sense 

 points to the work of forces, one of whose 

 essential properties is polarity that is, 

 equal and similar action in opposite direc- 

 tions. Now, this kind of correlation of 

 growth may be traced upwards from simple 

 minerals through all the infinite complica- 

 tions of the organic world. It is unques- 

 tionably the basis of many of the correla- 

 tions of growth prevailing in plants and 

 animals. It is seen in the symmetrical ar- 

 rangement of all vegetable and of all animal 

 forms. A central axis is traceable in them 

 all, and the bilateral or radiated arrange- 

 ment of their subordinate parts is one of the 

 most fundamental and universal of all the 

 correlations of growth. ARGYLL Reign of 

 Law, ch. 5, p. 144. (Burt.) 



668. CORRELATION OF SCIENCES 

 Chemistry and Microscopy Aid Each 

 Other. It should always be remembered 

 that a chemical report and a bacteriological 

 report should assist each other. The former 

 is able to tell us the quantity of salts and 

 condition of the organic matter present; 

 the latter the number and quality of micro- 

 organisms. Neither can take the place of 

 the other, and, generally speaking, both are 

 more or less useless until we can learn, by 

 inspection and investigation of the source 

 of the water, the origin of the organic mat- 

 ter or contamination. Hence a water report 

 should contain not only a record of physical 

 characters, of chemical constituents, and of 

 the presence or absence of micro-organisms, 

 injurious and otherwise, but it should also 

 contain information obtained by personal 

 investigation of the source. Only thus can 

 a reasonable opinion be expected. NEWMAN 

 Bacteria, ch. 2, p. 51. (G. P. P., 1899.) 



669. CORRESPONDENCE BETWEEN 

 EMBRYOLOGY AND GEOLOGY FAILS IN 

 PARTICULARS When we rigorously com- 

 pare the development of any animal what- 



ever with the successive appearance of ani- 

 mals of the same or similar groups in 

 geological time, we find many things which 

 do not correspond not merely in the want 

 of links which we might expect to find, but 

 in the more significant appearance, prema- 

 turely or inopportunely, of forms which we 

 would not anticipate. DAWSON Facts and 

 Fancies in Modern Science, lect. 1, p. 66. 

 (A. B. P. S.) 



670. CORRESPONDENCE BETWEEN 

 PITCH OF SOUND AND COLOR Incon- 

 ceivable Number of Light-waves. The pitch 

 of sound is wholly determined by the rapid- 

 ity of the vibration, as the intensity is by the 

 amplitude. What pitch is to the ear in acous- 

 tics, color is to the eye in the undulatory the- 

 ory of light. Tho never seen, the lengths of 

 the waves of light have been determined. 

 Their existence is proved by their effects, and 

 from their effects also their lengths may be 

 accurately deduced. This may, moreover, be 

 done in many ways, and, when the different 

 determinations are compared, the strictest 

 harmony is found to exist between them. 

 This consensus of evidence is one of the 

 strongest points of the undulatory theory. 

 The shortest waves of the visible spectrum 

 are those of the extreme violet ; the longest, 

 those of the extreme red; while the other 

 colors are of intermediate pitch or wave- 

 length. The length of a wave of the extreme 

 red is such that it would require 36,918 of 

 them, placed end to end, to cover one inch, 

 while 64,631 of the extreme violet waves 

 would be required to span the same distance. 

 Now, the velocity of light, in round num- 

 bers, is 190,000 [186,414, Flammarion, 

 " Popular Astronomy," p. 318] miles per sec- 

 ond. Reducing this to inches, and multiply- 

 ing the number thus found by 36,918, we 

 find the number of waves of the extreme red, 

 in 190,000 miles, to be four hundred and 

 fifty-one millions of millions. All these 

 waves enter the eye, and strike the retina 

 at the back of the eye in one second. In a 

 similar manner, it may be found that the 

 number of shocks corresponding to the im- 

 pression of violet is seven hundred and 

 eighty-nine millions of millions. TYNDALL 

 Lectures on Light, lect. 2, p. 62. (A., 1898.) 



671. CORRESPONDENCE DEMANDS 



A PLAN The Natural Includes the Supernat- 

 ural. Here the supermaterial, and in this 

 sense the supernatural, element that is to 

 say, the ideal conformity and unity of con- 

 ception is the one unquestionable fact in 

 which we recognize directly the working of 

 a mind with which our own has very near 

 relations. Here, as elsewhere, we see the 

 natural, in the largest sense, including and 

 embodying the supernatural ; the material, 

 including the supermaterial. No possible 

 theory, whether true or false, in respect to 

 the physical means employed to preserve the 

 correspondence of parts which runs through 

 all creation, can affect the certainty of that 



