MB. MARTINEAU ON EVOLUTION. 315 



pie substances are really simple. Each yields a spectrum having lines 

 varying in number from two to eighty lines every one of which implies 

 the intercepting of ethereal undulations of a certain order by something 

 oscillating in unison or in harmony with them. Were iron absolutely 

 elementary, it is not conceivable that its atom could intercept ethereal 

 undulations of eighty different orders : though it does not follow that 

 its molecule contains as many separate atoms as there are lines in its 

 spectrum, it must clearly be a complex molecule. The evidence thus 

 gained points to the conclusion that, out of some primordial unit, the 

 so-called elements arise by compounding and recompouuding ; just as 

 by the compounding and recompounding of elements there arise oxides, 

 and acids, and salts. And this hypothesis is entirely in harmony with 

 the phenomena of allotropy. Various so-called elementary substances 

 have several forms under which they present quite different properties. 

 The semitransparent, colorless, extremely active substance commonly 

 called phosphorus may be so changed as to become opaque, dark red, 

 and inert. Like changes are known to occur in some gaseous, non-me- 

 tallic elements, as oxygen ; and also in metallic elements, as antimony. 

 These total changes of properties, brought about without any changes 

 to be called chemical, are interpretable only as due to molecular ar- 

 rangements ; and, by showing that difference of property is produced 

 by difference of arrangement, they support the inference otherwise to 

 be drawn, that the properties of different elements result from differ- 

 ences of arrangement produced by the compounding and recompound- 

 ing of ultimate homogeneous units. Thus Mr. Martineau's objection, 

 which at best would imply a turning of our ignorance of the nature of 

 elements into positive knowledge that they are simple, is, in fact, to be 

 met by two sets of evidences, which distinctly imply that they are com- 

 pound. 



Mr. Martineau next alleges that a fatal difficulty is put in the way of 

 the General Doctrine of Evolution by the existence of a chasm between 

 the living and the not-living. He says : " But with all your enlarge- 

 ment of data, turn them as you will, at the end of every passage which 

 they explore, the door of life is closed against them still." Here again 

 our ignorance is employed to play the part of knowledge : the fact that 

 we do not know distinctly how an alleged transition has taken place is 

 transformed into the fact that no transition has taken place. We have 

 over again the mode of argument which until lately was thought con- 

 clusive because the genesis of each species of creature had not been 

 explained, therefore each species must be specially created. Merely 

 noting this, however, I go on to remark that scientific discovery is day 

 by day narrowing the chasm, or, to use Mr. Martineau's metaphor, 

 " opening the door." Not many years since, it was held as certain 

 that the chemical compounds distinguished as organic could not be 

 formed artificially. Now, more than a thousand organic compounds 

 have been formed artificially. Chemists have discovered the art of 



