FRAGMENTS OF SCIENCE. 



7^7 



tered. M. Gain further found that moisture 

 in the soil favors and increases the number 

 of fruits and seeds, while a dry soil promotes 

 larger and heavier seeds. Plants in dry soil 

 have more roots than those in wet soil. 

 While the tenure of moisture has little influ- 

 ence on the number of tubers, they are larger 

 and heavier in a moist soil ; yet they are less 

 perfect than tubers grown under relatively 

 dry conditions. Thus, while greater moist- 

 ure is favorable to a larger immediate re- 

 turn, it is less promotive of perfection in the 

 reproductive parts, and eo favors the indi- 

 vidual rather than the vigor of the species. 



Geography in the Middle Ages. — The 



first number of Herr M. Konrad Miller's work 

 on the Oldest Maps of the World is devoted 

 to the map of the universe of St. Beatus, a 

 Spanish theologian, who died a. d. 798. It 

 was made in connection with the author's 

 Commentary on the Apocalypse, to point out 

 the regions assigned to the several apostles, 

 and exists in many copies of different ages, 

 the maps in which differ but little from 

 one another. One of the most famous of 

 these copies is the one called the Manuscript 

 of St. Sever, in the Bibliotheque Nationale, 

 Paris, of about a. d. 1050. The map includes 

 the whole world in an oval inclosed by a blue 

 sea border containing large and fierce-look- 

 ing fishes and red objects which might be 

 taken for red slugs, but which are really ves- 

 sels. At the extreme east (north and south 

 being at the ends of the axis of the oval) 

 Temptation is represented in a naturalistic 

 style. At the point where the earthly para- 

 dise was supposed to exist, Adam is bash- 

 fully making symbolical gestures, and Eve, 

 bold and full of initiative, is picking the ap- 

 ple, both entirely naked. It appears clear as 

 the light of the sun that all the wrong is on 

 Eve's side. In the extreme west are Tangier 

 and Cordova at the entrance of a sea that 

 washes Majorca and Minorca, then Sardinia, 

 Corsica, Cyprus, and Crete, and turns to the 

 north in the Adriatic Gulf and the Helles- 

 pont. The Fortunate Islands, in the midst 

 of numerous fishes, are Madeira and the Ca- 

 naries, and, together with the British Isles 

 and perhaps Iceland, mark the western limit 

 of the world. In the south the Red Sea, 

 bright scarlet, is separated from the Medi- 

 terranean by the whole of Egypt and Pales- 



tine in a way to defy the most enterprising 

 isthmus-borers. No pains are taken to give 

 the contours of the coasts, the bays, or the 

 gulfs. Spain is reduced to a triangle, one 

 side of which, curved, is formed by the 

 Pyrenees, as if they were a fringe, while the 

 other two sides are the shore, straight. The 

 details of the geography of the several coun- 

 tries are curious, but can not be described 

 here. Many strange things appear in Africa, 

 too, while the origin of the Nile in a great 

 lake is indicated in the clearest manner. 



Origin of Honeydew. — M. Gaston Bon- 

 nier's studies of the formation of honeydew 

 have led him to the conclusion that not only 

 is it elaborated through the agency of aphi- 

 des, but it is also exuded directly, under prop- 

 er conditions, by the leaves of the trees. He 

 has observed that under conditions of a con- 

 siderable difference between the tempera- 

 tures of the day and the night, when no in- 

 sects can be found, a sugary liquid falls after 

 sunset in drops from certain trees ; and after 

 wiping the leaf with absorbent paper, he 

 found the minute droplets issuing from the 

 stomata. This was observed on the epiceas, 

 silver firs, Scotch pines, Austrian pines, oaks, 

 maples, aspens, poplars, alders, birches, 

 vines, and various herbaceous plants. Yet 

 the aphides are the more frequent- cause of 

 the production of honeydew. Their work 

 is done mostly in the daytime and is sus- 

 pended during the night, while the direct 

 production of honeydew takes place at night 

 and ceases in the daytime. It is promoted 

 by the interposition of cool nights between 

 hot and dry days, and is favored by increase 

 in hygrometric conditions and darkness. The 

 exudation can be provoked artificially by 

 dipping the branches into water and then 

 placing them in the dark in a saturated at- 

 mosphere. Under these conditions the leaves 

 may be caused to produce honeydew when 

 those on the trees from which they were 

 taken do not. Although bees will go to col- 

 lect any sweet substance when they can get 

 no better, they always prefer the best they 

 can find. When mellifluous plants are bloom- 

 ing abundantly, they pass the honeydew by ; 

 but when mellifluous flowers are scarce, they 

 gather honeydew. The chemical composi- 

 tion of honeydew is various; but that nat- 

 urally exuded approaches that of the honey 



