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SCIENCE. 



[N. S. Vol. XXIV. No. 621. 



mately associated with all that pertains to 

 organic life on this old round world of 

 ours. 



The immortal Darwin gave it a mighty 

 impetus when he presented to the world 

 his doctrine of natural selection, and the 

 researches of Brooks in our own country 

 place us on a high plane in this beautiful 

 study. Some day the world will be startled 

 by the results of biological research. 



Perhaps the most remarkable discovery 

 recently made in embryology, a branch of 

 biology, is that we can trace the evolution 

 of a species through its development in the 

 embryo, that is to say, the very beginning 

 of the embryo is identical with the most 

 ancient form; throughout its development 

 we see its evolution to its present condition. 

 Koch's discovery of the bacillus of tubercu- 

 losis made another epoch in the science of 

 biology. 



Brooks has said: "It may be some day 

 we shall be able to construct a living or- 

 ganism by the combination of the proper 

 elements. ' ' Atwater has trodden upon al- 

 most forbidden ground in his remarkable 

 investigations of the calorific value of 

 foods in the human subject— indeed, has 

 gone so far in this splendid research that 

 we may dare hope some day to measure the 

 food value of a thought. 



I am aware, as already remarked, this is 

 treacherous ground upon which to build a 

 solid foundation, but the better day has 

 come when the earnest seeker for truth is 

 no longer hindered in his onward course by 

 that ancient barrier 'hitherto shalt thou 

 come and no further.' 



In the broad light of the twentieth cen- 

 tury the investigator, the university man, 

 untrammeled by fear, save the fear of 

 error, will rise to heights of knowledge 

 never dreamed of in our philosophy. 



I verily believe that the storehouse of 

 God's truth is like unto the 'widow's 



cruse,' take from it as we may, it will 

 never be emptied of its rich, its priceless 

 treasures. 



To-day we are but learning single notes. To- 

 morrow we shall blend tbem into chords. The 

 hour will chime when all humanity shall know 

 the law of harmony — when every note in every 

 chord shall find its part in the sublime oratorio 

 of universal life, 



JoHzsr A. Brashear. 



SCIENTIFIC BOOKS. 

 Outline of the Evolution of Weights and 



Measures and the Metric System. By 



William Hallock and Herbert T. Wade. 



The Macmillan Company. Price, $2.25. 



The science of metrology in its evolution 

 has been regarded by many as furnishing the 

 best means of tracing the history of the exact 

 sciences. If this be true, we should welcome 

 this carefully prepared treatise by Hallock 

 and Wade — men fitted by taste, training and 

 experience to write upon this topic. 



We have here presented a systematic general 

 history of weights and measures, the scientific 

 methods by which units and standards have 

 been determined, the correct standards by 

 which the units are represented, and the pres- 

 ent aspect of modern systems of weights and 

 measures together with the difficulties and 

 advantages involved in any proposed change. 



A work of this sort is especially opportune 

 just now when a determined effort is being 

 made to introduce the metric system in this 

 country. It will give much useful informa- 

 tion to help those in doubt to decide whether 

 a change in our metrology is advisable or not. 

 Whatever the personal views of the authors 

 are on this subject, they have wisely refrained 

 from giving them undue prominence. 



The work contains chapters on the begin- 

 nings and development of the science of 

 metrology, origin and development of the 

 metric system, extension of the metric system 

 throughout Europe and elsewhere, weights and 

 measures in the United States, the metric 

 system in the various arts and trades, elec- 

 trical units, standards and tables of useful 

 constants and equivalents. 



