FRAGMENTS OF SCIENCE. 



573 



clouds is shown when they sink rapidly ; the 

 dust is theu seen at their edges and gives 

 the iridescent or nacreous appearance fre- 

 quently observed. 



Horticulture an Object Lesson in Evolu- 

 tion. — The study of horticulture and agricul- 

 ture is held up in Garden and Forest as hav- 

 ing a distinct value as a factor in furnishing 

 exercise for certain powers of the mind, and 

 as providing in the systematic examination 

 of the principles of those branches training 

 than which no science affords better. Prof. 

 Bailey, in Science, mentions some of the uses 

 and applications of horticulture in discussing 

 the theory of evolution. It shows the de- 

 velopment of life in actual operation. More 

 than six thousand species of plants are culti- 

 vated, and most of these have been broken 

 up into varied forms by the hand of man. 

 Some species have produced thousands of 

 distinct forms, and the methods of produc- 

 tion of many of them are on record. In 

 place of arguments as to the probable in- 

 fluence of climate upon plants, the horticul- 

 turist cites definite cases, so that there is no 

 conjecture about the matter. Instead of 

 speculating upon the transmission of ac- 

 quired characters, the horticulturist furnishes 

 proof of such transmission. Paleontology 

 brings disjointed evidence in regard to the 

 influence of selection and probable changes 

 from environment, while the horticulturist 

 brings examples before our eyes to prove 

 that he can modify and mold vegetation at 

 his will. The horticulturist creates new spe- 

 cies, and shows you numbers of cultivated 

 plants of which no one knows the original 

 form, because the ones with which we are 

 acquainted are so unlike the type that the 

 two can never be connected. This is only a 

 single line of inquiry, and other illustrations 

 quite as striking can be given to show that 

 there is an abundant field for scientific re- 

 search and profound thought in horticultural 

 science as such. 



Physical Characteristics of Cuba. — "In 



Cuba," says Mr. J. W. Spencer, in his paper 

 on the Geographical Evolution of Cuba, " are 

 mountains higher than any on the eastern 

 side of North America ; extensive plains as 

 level as those of the Atlantic coast ; valleys 

 formed at the base-level of erosion, and deep 



canons carved out by the youngest streams ; 

 the remains of enormous beds of limestones 

 mostly swept off the country, and coral reefs 

 and mangrove islands extending the coastal 

 plains into the sea ; sea cliffs, caves, and ter- 

 races of great and little elevation ; drowned 

 valleys deeper than the fiords of Norway 

 indenting the margin of the insular mass ; 

 caverns innumerable and rivers flowing under- 

 ground; rifts through mountain ridges and 

 rock basins ; tilted, bent, and overturned 

 strata, dislocated and faulted in modem 

 times, so as to make youthful mountain 

 ranges ; metamorphic rocks and rocks igne- 

 ous, and these again altered to secondary 

 products ; old base-level plains or those 

 modified and reaching across the island, 

 having insular ridges of older formations 

 rising out of them, and with the surfaces 

 scarcely incised by the streams ; residual 

 soils from the decomposition of the rocks 

 and sea-made loams and gravels ; in short, 

 so rapidly are the geologic forces working 

 that one can see a greater variety of struc- 

 ture and learn more of dynamic geology in 

 Cuba than on more than half of the tem- 

 perate continent." The island is seven hun- 

 dred and fifty miles long and from twenty-five 

 to one hundred and twenty miles wide. In the 

 western part the ridges of mountains culmi- 

 nate in a point with an altitude of twenty-five 

 hundred feet, but the principal topographic 

 relief is along the southern coast of the 

 eastern extension of the island where Pico 

 Tarquino rises from the Sierra Maestra to 

 an elevation of eighty-four hundred feet. 

 The central portion of the island is gener- 

 ally a plain of from two hundred to four 

 hundred feet above tide, which bears many 

 scattered and interrupted ridges like islands 

 in a sea. Mr. Spencer's study is chiefly con- 

 fined to this part of the island. 



A Word in Favor of Woodpeckers. — The 



food of woodpeckers has been studied, with 

 a view to determining whether they are in- 

 jurious or beneficial in the economy of api- 

 culture and forestry, by F. E. L. Beal, who 

 concludes that they do far more good in the 

 destruction of insects than harm with the 

 little fruit and grain they eat and the sap 

 they suck. Of seven species considered, the 

 author regards the downy woodpecker as the 

 most beneficial, it being a great eater of in. 



