MISCELLANY. 



383 



microscopes were a rarity in America. In 

 the year 1840, when the United States Ex- 

 ploring Expedition to the South Seas, under 

 Commander Wilkes, was fitting out, it was 

 thought necessary to have a microscope. 

 The various makers of scientific and philo- 

 sophic instruments were applied to, but none 

 of them could furnish the expedition with 

 the thing desired. In this dilemma a private 

 individual was appealed to, and an instru- 

 ment thus finally obtained, in the shape of 

 an inferior French microscope. How, then, 

 did the present flourishing state of affairs 

 come about ? Simply by the genius of a 

 self-taught man. He was a backwoodsman, 

 and had pored over an old cyclopaedia, and 

 turned the optical knowledge contained 

 therein, as far as in him lay, to sound prac- 

 tical account. At the age of twelve years 

 he made his first lens. One day he happened 

 to be shown a microscope constructed by 

 Chevalier, of Paris, and the thought struck 

 him that he would try to make a similar in- 

 strument. He succeeded, and his glasses 

 were able to resolve a test which similar ob- 

 jectives of the first English opticians had 

 hitherto failed to define. His name was 

 Charles Spencer. And now his pupil Tolles, 

 and Wales, a pupil of Smith and Beck, with 

 Gronow, Zentmayer, and others, form a 

 galaxy of American mathematical instru- 

 ment talent that appears from recent ac- 

 counts to be holding its own against the 

 whole of the world. Is there not here a 

 ground for the hope I expressed a little 

 while ago ? Surely after this example of 

 Spencer, the young backwoodsman, many 

 here present may live to see the day when 

 a finished microscope shall be presented to 

 their delighted gaze by the hands of an 

 Australian townsman, at least, if not by an 

 Australian bushman." 



The ImproTement of Haman Life. — An 



extremely valuable paper by Dr. Edward 

 Jarvis, on " Political Economy of Health," 

 published in the Fifth Annual Report of the 

 Massachusetts Board of Health, groups to- 

 gether very strikingly the vital statistics of 

 various countries, to show the effect of the 

 advance of civilization in protracting the 

 term of human life. By better adaptation 

 of means, circumstances, and habits, says 

 Dr. Jarvis, man's life has been expanded. 



his strength increased, and his days on 

 earth prolonged. By the improvements in 

 agriculture and in vegetable and animal life, 

 he has obtained better and more constant 

 food, and is therefore better nourished. By 

 the improvements in the arts he is better 

 clothed and housed, better protected from 

 the elements. The progress of civilization 

 is best manifested in the progress of vitality. 

 There is less sickness, and that which visits 

 humanity is less destructive than in former 

 ages. 



In ancient Rome, in the period 200 to 

 500 years after the Christian era, the aver- 

 age duration of life in the most favored 

 class was 30 years. In the present century 

 the average longevity of persons of the same 

 class is 50 years. In the sixteenth century 

 the average longevity in Geneva was 21.21 

 years ; between 1814 and 1833 it was 40.68, 

 and as large a proportion now live to 70 as 

 lived to 43 three hundred years ago. Ih 

 1693 the British Government borrowed 

 money by selling annuities on lives from 

 infancy upward, on the basis of the aver- 

 age longevity. The treasury received the 

 price and paid the annuities regularly as 

 long as the annuitants lived. The contract 

 was mutually satisfactory and profitable. 

 Ninety-seven years later Mr. Pitt issued 

 another tontine or scale of annuities, on the 

 basis of the same expectation of life as in 

 the previous century. These latter annui- 

 tants, however, lived so much longer than 

 their predecessors, that it proved to be a 

 very costly loan for the Government. It 

 was found that while 10,000 of each sex in 

 the first tontine died under the age of 28, 

 only 5, 7*72 males, and 6,416 females in the 

 second tontine died at the same age one 

 hundred years later. The average life of 

 the annuitants of 1693 was 26.5 years, 

 while those of 1*790 lived 33 years and 9 

 months after they were 30 years old. 



From these facts, says Dr. Jarvis, it is 

 plain that life, in many forms and manifes- 

 tations, and probably in all, can be ex- 

 panded in vigor, intensity, and duration, un- 

 der favorable influences. For this purpose 

 it is only necessary that the circumstances 

 amid which, and the conditions in which, 

 any form of life is placed, should be brought 

 into harmony with the law appointed for its 

 being. By this means the intelligent world 



