NOVEMBEK 30, 1917] 



SCIENCE 



539 



suiner becoming tlie sole producer of a ma- 

 terial vital to that line of manufacture. 

 When expert scientific knowledge is involved 

 it is well that scientific men be alive to the 

 consequences of certain lines of activity. 



Four years ago this country imported an- 

 nually about half a million dollars worth of 

 optical glass, chiefly from Schott in Jena, 

 Mantois in Paris and to some extent from 

 Chance in England. At the outbreak of the 

 war the German supply ceased, while the 

 French and English supplies were limited to 

 that not required for war purposes. Six of 

 the large consumers of optical glass, a gov- 

 ernment bureau and three glass manufacturers 

 at once started experimental work in this 

 country on the manufacture of optical glass. 

 The entire normal demand for this material is 

 barely sufficient to pay overhead and a modest 

 profit to a single manufacturing concern. 

 But two of these would-be producers have 

 faced the very considerable development ex- 

 pense and brought their production to a fac- 

 tory basis. One of them is a large consumer 

 of optical glass, the other a large manufac- 

 turer of plate glass. 



The situation faced by the independent 

 consumer is a difficult one. He naturally can 

 not depend upon his largest competitor for his 

 raw material. Neither can the plate-glass 

 manufacturer be depended upon as a perma- 

 nent source of supply since his large orders 

 for his regular product are much more re- 

 munerative. The outlook is therefore rather 

 dismal both for the independent consumer and 

 for the future manufacture of optical glass in 

 America. 



Optical glass manufacture, like so many 

 other industries newly taken over in this 

 country, is extremely sensitive to the favor of 

 the capitalist as well as of the scientific ex- 

 pert and skilled laborer. Optical glass has 

 been successfully made in this country in 

 small experimental batches at various times 

 for at least thirty years back, but no one would 

 risk the necessary capital in a business with 

 a demand so circumscribed and a margin of 

 profit so limited. At present a concern de- 

 voted exclusively to optical glass, booking the 



entire American demand might weather the 

 return to normal trade conditions. With the 

 business split into at least two parts, one chief 

 producer a large consumer, another operating 

 it as a trivial side issue, the industry is un- 

 likely to survive. 



P. G. Nutting 

 Pittsburgh, 

 October, 1917 



A NOTE ON THE "AGE AND AREA" 

 HYPOTHESIS 



Professor DeVries' ^ recent endorsement of 

 the hypothesis advanced by Willis that the 

 range of any plant, barring barriers, depends 

 upon the age of the species, is a most curious 

 illustration of how uncritical a man becomes 

 who is obsessed with a theory. The Willis hy- 

 pothesis has already been satisfactorily dealt 

 with by Sinnott^ in the pages of Science and 

 I wish only to add one or two brief comments. 



Neither Willis nor DeVries appear to have 

 any knowledge of or interest in the facts of 

 paleontology, certainly the latter, since he is 

 an evolutionist of a sort, might have selected 

 a name for his supposed factor that had not 

 already been used in a perfectly definite way 

 for a process diametrically the opposite of 

 saltation. This has all been well said by 

 former critics and I mention it in the present 

 connection merely as more cloth off the same 

 piece as the adoption of the Willis hypothesis. 



Eegarding barriers, we are familiar with 

 certain gross kinds such as mountain ranges 

 and seas, but who can successfully formulate 

 the interrelations of organisms with one 

 another and with their environment and the 

 less obvious but no less real barriers that result 

 from these correlations? One is reminded of 

 Darwin's classic explanation of the relation- 

 ship between cats and red clover, in which 

 case spinsters might prove an effective barrier 

 to field mice and offer optimum conditions for 

 the spread of clover. 



With reference to New Zealand, a philo- 

 sophic botanist would have to account for 

 very many plant radiations of different ages 

 and from different directions — certainly the 



1 Science, N. S., Vol. 45, pp. 641-642. 



2 Science, N. S., Vol. 46, pp. 457-459. 



