692 POPULAR SCIENCE MONTHLY. 



petals small, purplish, and in one species tliey are wanting; the axil- 

 lary flowers of Bracenia purpurea are small and dull purple ; in the 

 common papaw the lurid purple flowers are large and adapted to 

 Diptera, as are probably the lurid purple flowers of Calycanthus. 

 Blue flowers may revert to red, white, or yellow. The fringed 

 Polygala of Britain is usually bright blue, but often reverts to pink 

 and white; there is a pure white variety of the blue-eyed grass; 

 Mertensia virginica is purple-blue, rarely white; the larkspur is 

 bright blue, sometimes white, and a white variety of the purple 

 Trillium frequently occurs; there is, indeed, no improbability of a 

 white-flowered form of every species being discovered. Viola cal- 

 carata is normally blue, but sometimes changes to the ancestral 

 yellow. 



The possession of a strong scent may, however, in many instances 

 more than compensate for the absence of color. This is well illus- 

 trated in Lepidium sativum. The flowers are small and inconspicu- 

 ous and in rainy weather do not fully open, yet, as it is odoriferous, 

 Miiller found it more abundantly visited by insects than any other 

 crucifer. It is their strong odor, rather than their color, that ren- 

 ders so many umbellifers so attractive to a great variety of insects. 

 Xocturnal flowers, which are visited by moths, are usually white 

 and sweet-scented, though the evening primrose is yellow and Sapo- 

 naria officinalis is rose-colored. Koliler and Schiibeler have shown 

 that a larger proportion of white flowers are fragrant than of any 

 other color. Of 1,193 white flowers examined by them, 187 were 

 odoriferous; of 951 yellow, 75; of 923 red, 85; of 594 blue, 31. 

 But neither color nor odor will long alone serve to insure the visits 

 of insects. The common elderberry exhibits the disadvantages 

 which may attend the want of honey when there is but a limited 

 supply of pollen. There are great masses of odoriferous flowers 

 which convert the shrub into a huge bouquet, but it blooms at mid- 

 summer, when it must contend with many nectar-yielding plants. 

 As a result, it is almost wholly deserted by insects. Only four spe- 

 cies of flies have been taken upon it, and repeatedly the blossoms 

 were examined without discovering a single visitor, and yet upon the 

 jewel-weed and the red-osier cornel, a few yards away, scores were 

 at work. 



Among the more recent applications of electricity is one for the desic- 

 cation of Avood, by the Kndon Bretonncau method, by wliicli wood is made 

 as fit for use for certain exact processes in as many months as it has for- 

 merly taken years. It is also proposed by Mr. Shaw, an English raining 

 engineer, to substitute water and steam for gunpowder in mine blasts, a 

 cartridge of water being placed instead of the powder cartridge, and 

 vaporized by passing the electrical current through it. 



