528 



THE POPULAR SCIENCE MONTHLY. 



In his late work on the "Physiology of 

 Circulation," Dr. Pettigrew gives the follow- 

 ing* as the rate of the heart-beats in man at 

 different periods of life : In the human foe- 

 tus the heart beats 140 times per minute ; 

 at birth, 130; second year after birth, 100; 

 third year, 90 ; fourteenth year, 80 ; mid- 

 dle age, 70 ; old age, 60, or even less. The 

 variation in the frequency of the beat of the 

 heart in the lower animals is still more re- 

 markable. 



From the United States statistics, it ap- 

 pears that the percentage of insanity, idi- 

 ocy, etc., is greater among the white popu- 

 lation of this country than among the 

 black. Thus, among the whites, one in 

 2,253 is deaf and dumb ; among the colored 

 race (blacks and mulattoes), only one in 

 3,780 ; insane whites, one in 943 ; colored, 

 one in 2,750 ; idiotic whites, one in 1,575 ; 

 colored, one in 1,530. The statistics of 

 blindness, however, are more unfavorable 

 for the colored race: blind whites, one in 

 2,000; colored, one in 1,469. The insane 

 females, both white and black, outnumber 

 the insane males, 19,202 against 18,179; 

 but the male idiots are greatly in excess of 

 the females 14,476 against 10,046. 



There is found in Bombay a minute 

 variety of ants which surround their nests 

 with a series of concentric circular walls 

 an inch or an inch and a half high, and 

 about the same distance apart, the inner- 

 most wall being the highest. The object 

 of these walls or fortifications is not yet 

 known. 



During a botanical exploration of the 

 region around the river Coanza, in Lower 

 Guinea, Dr. Welwitsch's party found their 

 supply of provisions exhausted. The men 

 accordingly went in search of food, with 

 senses quickened by hunger. They were 

 so fortunate as to discover an enormous 

 mushroom, as large as an umbrella, which 

 made soup enough to satisfy the hunger of 

 20 men. This specimen was the first of the 

 species seen by Welwitsch, but subsequent- 

 ly he often met with it, and learned that 

 these great mushrooms are brought to mar- 

 ket at Pungo Adongo by the natives, and 

 there sold at from one to three pence each, 

 according to size. 



By act of Parliament of the year 1843, 

 mechanics' institutes, literary and scien- 

 tific associations, and the like, were ex- 

 empted from local taxation in England. 

 The Government now proposes to do away 

 with the exemption, thus imposing a tax on 

 knowledge. If the measure succeeds, many 

 societies must close their doors, and the 

 work of popular education will receive a 

 serious check. 



A " memorial volume," to commemorate 

 the services rendered to science by the late 



Prof. Liebig, is to be published by the Roy- 

 al Bavarian Academy of Sciences, of which 

 body he was president. The volume will 

 contain an obituary notice of the deceased, 

 and three separate dissertations upon the 

 services rendered by him to physiology, 

 agriculture, and theoretical chemistry, to be 

 written by Profs. Bischof, Vogel, and Erle- 

 meier. 



The amount of tobacco paying duty and 

 cleared for consumption in Great Britain 

 steadily increases. Thus in 1841 it aver- 

 aged 13 \ oz. per capita; in 1851, 16^ oz. ; 

 In 1861, 19 "r oz. ; and in 1871, 21 oz. 



The average number of persons per 

 house, in various cities of the United States, 

 is as follows : New York, 14.72 ; Cincin- 

 nati, 8.81 ; Brooklyn, 8.64 ; Boston, 8.46 ; 

 Jersey City, 8.37 ; Hartford has 5.56 ; 

 Rochester, 5.36 ; and Toledo, the lowest, 

 5.20. The densest population is that of 

 the Fourth Ward, New York, where there 

 are 24.61 persons to each dwelling. 



The Russian Government is about to 

 construct a railroad from Nijni-Novgorod 

 on the Volga, to the Japan Sea, about 4,200 

 miles. This line, in conjunction with that 

 from Nijni-Novgorod to St. Petersburg, will 

 connect the Baltic Sea with the Pacific. 

 The road will run east in latitude 56, 850 

 miles to Tobolsk, crossing the Ural Moun- 

 tains. From Tobolsk it will take a south- 

 east course 1,500 miles to Irkutsk, on Lake 

 Baikal (latitude 53). The remainder of the 

 route is not yet determined on, but it is ex- 

 pected that work will be commenced on the 

 western end during the present year. 



Lake Neahtawanta, near the Oswego 

 Falls, is a noted fishing-ground, containing 

 abundance of pickerel, pike, perch, bass, 

 and indeed nearly all the fresh-water fish. 

 But a sort of epizooty recently broke out 

 among the pickerel, which threatens to ut- 

 terly destroy all the fish of that species con- 

 tained in the lake ; indeed, it is believed 

 that they are already destroyed. The other 

 fish in the lake are not affected by the dis- 

 order. 



Dr. Lton Platfair has no very high 

 opinion of the value of English university 

 education. He said recently in Parliament 

 that " a Scotch university teaches a man 

 how to make a thousand a year, an English 

 university how to spend it." 



Mr. Benjamin Smith, of London, has 

 sailed for the north-pole in the yacht Diana. 

 Mr. Smith expects to join his supply-yacht, 

 the Samson, at Cobbe's Bay, on the north- 

 west of Spitzbergen, latitude 80. From 

 that point he will push as far northward as 

 the ice will permit. He purposes returning 

 home in one year at the farthest. 



