A WEEKLY ILLUSTRATED JOURNAL OF SCIENCE. 



" To the solid ground 

 Of Nature trusts the mind which builds for aye." — WORDSWORTH. 



THURSDAY, NOVEMBER 7, il 



TWENTY YEARS. 



A REMINDER that to-day is the twentieth anni- 

 ^^ versary of the first issue of Nature, will not, 

 perhaps, be without interest to our readers, and certainly 

 affords food for reflection to those who in various capaci- 

 ties have been more or less closely connected with this 

 journal from the first. 



"When another half-century has passed," said Prof. 

 Huxley in our first number, " curious readers of the back 

 numbers of Nature will probably look on our best ' not 

 without a smile.' " 



It will probably be so, but though twenty years is 

 hardly a sufficient interval to make our smiles at our 

 earlier efforts supercilious, it is enough to test whether 

 progress has been made, and whether the forward path 

 is pursued with growing or with waning force. 



As regards this journal itself, we may claim that it has 

 not disappointed the hopes of its founders, nor failed in 

 the task it undertook ; and we make this claim all the 

 more emphatically because we feel that what has been 

 accomplished has not been due to our own efforts so 

 much as to the unfailing help we have always received 

 from the leaders in all branches of natural science. This 

 help has not been limited to their contributions to our 

 columns, but has consisted also of advice and suggestions 

 which have been freely asked and as freely given. Not 

 the least part of our duty, and even privilege, to-day is 

 to state openly how small our own part has been, and 

 to render grateful thanks to those to whom it is chiefly 

 due that Nature has a recognized place in the machinery 

 of science, and has secured an audience in all parts of the 

 civilized world. 



We do not wish, however, to narrow our retrospect of 

 Vol. xli.— No. 1045. 



the last twenty years by confining our attention to the 

 measure of success which these pages have won. It has 

 been attained, as we have shown, by the aid of nearly all 

 the best-known scientific writers and workers.not in Britain 

 only but in many countries old and new ; and we cannot 

 believe that they would thus have banded themselves 

 together if evidence had not been given of an honest 

 desire for the good of science and for the " promotion of 

 natural knowledge," or if the attainment of these objects 

 had not been regarded by us as of more importance than 

 a journalistic success. Thus, on its twentieth birthday, 

 we would think not so much of the growth of Nature 

 as of the advance which in the last twenty years it has 

 chronicled. 



A formal history of science for that period would be a 

 formidable task, but it is already possible to discern what 

 will probably appear to posterity to be the most salient 

 characteristics of the last two decades. 



In the physical sciences, the enormous development 

 of the atomic theory, and the establishment of a con- 

 nection between the theories of electricity and light, are 

 perhaps the two main achievements of the years we are 

 considering. Methods of accomplishing the at first 

 sight impossible task of measuring atomic magnitudes 

 have been devised. Our own volumes contain some of 

 the most interesting papers of Sir William Thomson on 

 this subject, and the close agreement in the results 

 attained by very different methods is sufficient proof that, 

 if only approximations, they are approximations we mny 

 trust. The brilliant vortex atom theory of Sir William 

 Thomson has not as yet achieved the position of a proved 

 hypothesis, but has stimulated mathematical inquiry. A 

 number of very powerful researches have added to our 

 knowledge of a most difficult branch of mathematics, 

 which may yet furnish the basis of a theory which shall 

 deduce the nature of matter and the phenomena of 

 radiation from a single group of assumptions. 



The theory of gases has been extended in both direc- 



