EARTHQ UAKES. 3 59 



his brain is smaller than when he was a boy between seven and four- 

 teen, the age when he thought he knew the most. 



Dr. Paul Broca gave the following table of average brain-weights : 



From 1 to 10 years, 985" IB grammes (34 - 7 oz.). 



From 11 to 20 years, 1,465-27 " (51-68 oz.). 



From 21 to 30 years, 1,341-53 " (47'67 oz.). 



From 31 to 40 years, 1,410-36 " (49-74 oz.). 



From 41 to 50 years, 1,391-41 " (4907 oz.). 



From 51 to 60 years, 1,341-19 " (47'30 oz.). 



61 and upward, 1,326-21 " (46"77 oz.). 



By looking over Dr. Boyd's table it will be seen that heavy brains 

 generally belong to tall men ; and so, by our table of individuals, it 

 appears that the heaviest is that of Turgeneff, who was a man of large 

 size, while the lighter brains accompanied men of medium or short 

 stature. Women are generally shorter than men, and their brains 

 relatively smaller. Quatrefages says : " We have known for several 

 years that the stature has an influence upon the weight of the brain. 

 It can not be without influence upon the cavity by which the latter is 

 inclosed. Under similar circumstances in other respects, the weight 

 of the brain varies proportionately, or almost proportionately, to the 

 height." 



If we accept the above statement that the largest healthy brains 

 are found in the tallest persons, and add to it the phrenological rule 

 that brain-size is a true measure of mental power, it will follow that 

 giants have the greatest minds in the world, which is contradicted by 

 every day's experience. Dr. Ireland, in his work on idiocy and imbe- 

 cility, mentions two cretins, each six feet high ; several idiot Calibans, 

 six feet six inches ; several idiots described by Lomboso, one of whom 

 was eight and a half feet, another seven feet eight inches, with a sister 

 the same height. Large stature may be a general indication of large 

 brain-weight, but the latter can not be taken as a safe index of high 

 intellectual power. 







EARTHQUAKES. 



By Professor G. H. DARWIN, F. R. S. 



THE earthquake-shocks which have recently occurred in America 

 and Greece, and the great volcanic eruption in New Zealand, 

 have served to keep the subject vividly before us during many months 

 past, and have perhaps created in some alarmist minds an ungrounded 

 expectation that the earth is about to enter on a new period of Plu- 

 tonic activity. It is natural, then, to ask at the present time what is an 

 earthquake, and what are its causes. Notwithstanding the necessary 

 incompleteness in the answers which can be given to these questions, 

 yet a good deal more is known than appears to be the common prop- 

 erty of newspaper writers. The object, then, of the present article is 



