178 THE POPULAR SCIENCE MONTHLY. 



A class of vessels of much interest, on account of their great 

 destructive capabilities when the conditions are suitable, is the 

 torpedo vessel, of which the Ericsson (Fig. 7), now building, is a 

 representative; they are lightly constructed and provided with 

 powerful machinery to enable them to attain great speed, reach- 

 ing as high as twenty-eight to thirty-five miles per hour. They 

 are armed principally with torpedo-launching tubes from which 

 are ejected, by compressed air, automobile torpedoes, capable of 

 traveling at a rate of speed of twenty knots per hour at a pre- 

 determined depth. The boat or launching tube is trained directly 

 upon the target, and the torpedoes are expelled in a direct line 

 toward it, certain automatic rudders being acted upon by hydro- 

 static pressure to enable them to keep their course. The head is 

 fitted with a torpedo net-cutting device to enable the torpedo to 

 pass through the net protecting the ship's side and to explode 

 against the side by impact. The most noteworthy achievement 

 by this class of vessels was the blowing up and sinking of the 

 Blanco Encalada by the Almirante Lynch during the late Chilian 

 struggle. 



In closing this article it seems eminently proper to acknowl- 

 edge the distinguished services and untiring zeal of ex-Chief 

 Constructor Theodore D. Wilson, who for eleven years, or during 

 the period of rehabilitation, has most ably shaped the general 

 design and construction of the hulls of our war vessels. 



EVOLUTION AND ETHICS. 



BY PROF. THOMAS H. HUXLEY, F. E. S. 

 [Concluded. ] 



T ET us now set our faces westward, toward Asia Minor and 

 J-J Greece and Italy, to view the rise and progress of another 

 philosophy, apparently independent, but no less pervaded by the 

 conception of evolution.* 



* In ancient times it was the fashion, even among the Greeks themselves, to derive all 

 Greek wisdom from Eastern sources ; not long ago it was as generally denied that Greek 

 philosophy had any connection with Oriental speculation ; it seems probable, however, that 

 the truth lies between these extremes. 



The Ionian intellectual movement does not stand alone. It is only one of several spo- 

 radic indications of the working of some powerful mental ferment over the whole of the area 

 comprised between the JSgean and northern Hindustan during the eighth, seventh, and 

 sixth centuries before our era. In these three hundred years prophetism attained its apogee 

 among the Semites of Palestine ; Zoroasterism grew and became the creed of a conquering 

 race, the Iranic Aryans ; Buddhism rose and spread with marvelous rapidity among the 

 Aryans of Hindustan ; while scientific naturalism took its rise among the Aryans of Ionia. 



