2 NATURAL SCIENCE. July. 



The question proposed to our contributors was — How has the 

 " Challenger " Expedition advanced science ? And each was re- 

 quested to answer this question for his special field of knowledge. 

 One has answered the question on one line, another on another ; the 

 limits of space made it impossible to discuss all aspects of the 

 subject, and by leaving the mode of treatment to the discretion of the 

 different writers, greater variety has been obtained. In zoology, for 

 instance, this writer has dealt with the facts of distribution, that one 

 has plunged into pure morphology, yet another has detailed that 

 increase in knowledge of genera and species upon which the broader 

 results are based. But our readers must remember that there was 

 advance in every direction, and that what is implied by any one of 

 these writers is often as much and as valuable as that which is 

 explicitly stated. There is one section which, though outside our 

 usual scope, we are specially glad to publish, that, namely, written 

 by the navigating officer of H.M.S. " Challenger," now Assistant- 

 Hydrographer to the Admiralty, and discussing the results to hydro- 

 graphy and navigation. Here, at least, is something of which the 

 man in the street can see the value ; every addition to our knowledge 

 of the ocean currents, the ocean floor, the ocean winds, is an addition 

 to the safety of the sailor, to the ease and speed with which voyages 

 may be accomplished, and to the intercourse of the nations. Every 

 Briton is proud of Britannia's Navy; but let us remember that it is 

 something more than our empire's fighting machine, that it has been 

 in the past, and will be still more in the future, the servant of the 

 world, and a most potent agent in the peaceful union and advance of 

 all its peoples. 



Some Lessons from the " Challenger." 



In every great undertaking of this kind, where so many interests 

 are involved, and where so much depends on the accuracy and co- 

 ordination of small details, there must necessarily be some failures, 

 and this experience of failure is as valuable to future undertakings as 

 is the experience of success. Some of our contributors have mentioned 

 these weak points, in the hope that they will beguarded against by any 

 forthcoming expedition. Already the lesson of the " Challenger " has 

 led to great improvement in the methods of capture of oceanic animals. 

 It was often impossible to tell from the old method at what depth an 

 animal found in the net really lived ; so that animals of markedly 

 pelagic organisation were brought home labelled "2,000 fathoms" 

 or thereabouts. By the introduction of nets that can be opened and 

 closed while below the surface, these errors are now avoided. Again, 

 the enormous advance that has been made in the technique of 

 preparing organisms for microscopic examination cannot fail to 

 render the results of a future exploration even more valuable than 

 those of the " Challenger." Much histological work proved 



