252 THE POPULAR SCIENCE MONTHLY. 



Except a few small groups, most of which I can not admit as form- 

 ing distinct families, our North American moths may be divided into 

 ten groups, to each of which the term "family" is applied, just as we 

 have the same term given to certain similar groups of other animals, 

 such as the birds or fishes. These ten families are : 1. The Sphingi- 

 dce, or " hawk-moths," of which we have 91 species in our territory ; 

 2. The ^Egeriadce, or " clear-wings," of which there are catalogued 

 about 120 sorts ; 3. The Zygceniclce, or " clear - spots," comprising 

 over 60 kinds ; 4. The Bombycidm, or " spinners," of which there 

 are more than 400 species ; 5. The Noctuidce, or " owlet - moths," 

 with nearly 1,600 different kinds ; 6. The Geometridce, or "spanners," 

 with 500 species ; 7. The Pyralidce, or " snout-moths " ; and 8. The 

 Tortricidce, or " leaf -rollers," with over 400 kinds of each ; 9. The 

 Tlneidce, or " leaf -miners " ; and 10. The Pterophoridce, or " feather- 

 moths," the former a large family of minute and often brilliantly col- 

 ored species, the latter a smaller one containing curious slender moths, 

 having the wings split into feathery fingers or rays. These last two 

 groups are very incompletely known. 



[To be continued.] 



-+*+-- 



CONCERNING KEROSENE. 



Br Professor S. F. TECKHAM. 



A MODERN French writer has said : " In the domain of the use- 

 ful arts each age reveals characteristic tendencies. In the last 

 century, mankind had need to clothe itself cheaply. . . . The nine- 

 teenth century has wished for light." To the development of the pe- 

 troleum industry the gratification of this wish is mainly due ; yet, 

 while the products of petroleum are used in nine tenths of all the 

 dwellings of the land, but few of those who occupy them realize that 

 60,000 barrels of crude oil flow from the earth every day, that more 

 than 30,000,000 barrels are now stored above-ground in huge iron 

 tanks, and that 15,000 barrels are required to supply each day's de- 

 mand in the United States alone. Of this vast quantity, by far the 

 largest proportion is consumed as illuminating oil, or kerosene, for the 

 production of which a stream of oil is constantly flowing through six- 

 inch pipes from the oil-region of Western Pennsylvania to Baltimore, 

 Philadelphia, and Jersey City. In each of these cities establishments, 

 constructed for the purpose, convert the crude oil into various products, 

 principally illuminating oil, for the home market and an export trade 

 of vast proportions. In these refineries the oil is first allowed to settle 

 in large tanks, in which a small percentage of water and sediment 

 accumulates. From these tanks the oil is pumped into stills, holding 



