.2«8 



NA TURE 



[August 25, 1923 



means of the accompanying diagram (Fig. 3). The 

 period of time covered is the century beginning in 1820, 

 and while the years are displayed down the centre of 

 the diagram, the size (in inches) of the object glasses 

 and mirrors are shown respectively on the left- and 

 right-hand sides against the years of their erection. 

 Many other large instruments of interest, apart from 

 those that were records in size in their time, have 

 been inserted. 



No less interesting and important is the study of the 

 geographical distribution of large telescopes. For this 



at Cordoba. This instrument, although completed, has 

 not yet been erected. 



South Africa and Australia are both blank in this 

 respect, except that a 26-inch refractor is nearing 

 completion for the former, but it is hoped that in 

 the near future both these countries will be better 

 represented. 



The limit of size of a telescope, whether it be refractor 

 or reflector, for the accomplishment of useful work ha~ 

 by no means yet been reached, providing the instrument 

 be placed in a specially selected locality high up on 



160 160 120 8O 40 O 40 80 120 



REFRACTORS from 30-40 inches • REFLECTORS trom 60- 100 .ncmes O 



" 20 - 29 - • " " JO - »59 " o 



Fig. 4. — Geographical distribution of large telescopes. 



purpose the positions of the great telescopes have been 

 indicated on a chart of the world (Fig. 4). On this 

 diagram refractors from 30 to 40 inches aperture are 

 represented by large black spots, and those between 

 20 and 29 inches by small black dots. On the other 

 hand, reflectors from 60 to 100 inches in diameter are 

 indicated by large circles, and those from 30 to 59 

 inches by small circles. It will be seen that the very 

 large telescopes predominate in two main regions, 

 namely Europe and the United States of America with 

 Canada. Only one telescope of the ver}' large type is 

 situated in the southern hemisphere, and that is the five- 

 foot reflector for the Argentine National Observatory 



some extensive plateau, where the " seeing " is of a 

 high-class nature during the greater part of the year. 



This limit is at present only temporarily restricted 

 by the maximum limit that can be reached by those 

 whose work it is to cast the necessary glass blocks. 

 The mounting of even the largest telescope is now only 

 a mild engineering problem. 



It must not be forgotten, however, that large 

 telescopes are very expensive not only to construct 

 but also to house; yet experience has shown, at 

 any rate in the United States of America, that 

 when occasion arises an enthusiastic private donor 

 generally appears. 



Obit 



THE death is announced of Dr. Hermann Biggs, 

 Commissioner of Health, New York State, at the 

 age of sixty-three. After graduating at Belle vue Medical 

 College, Dr. Biggs studied in Berlin and Greifswald, 

 and returning to the United States in 1895, directed 

 the production of the first diphtheria antitoxin in that 

 country. In 1900 he became general medical officer 

 of the New York City health department, and there 

 established the first municipal bacteriological labora- 

 tory. This post he held until 1914, when he was 



NO. 2808, VOL, 112] 



u ary. 



appointed Commissioner of Health to New York 

 State. Under his administration the health of New 

 York City and State changed markedly for the better. 

 He organised a campaign against tuberculosis, and was 

 responsible for a body of wise health legislation. He 

 was a scientific director of the Rockefeller Institute, 

 and, for a short time, medical director of the League of 

 Red Cross Societies. He gave to his country and to the 

 world distinguished services, and preventive medicine 

 loses by his death an ardent disciple. R. T. H. 



