58 FIELD AND FOREST. 



The construction of a rail-way in September 1864 gave opportunity 

 for earth prevously undisturbed twelve feet below the surface. The 

 workmans' tools were carefully washed before use, and the earth placed 

 in new covered boxes which were sealed and preserved till May 1865. 



Twenty-four pots'were half filled Avith hot bed soil which had been 

 boiled to destroy all recent seeds the surface of which was covered with 

 lyi inches of the Loss leaving a space of two inches under the pane of 

 glass which covered the pot. The glass rested on a bit of wood one twelfth 

 of an inch thick thus leaving an opening of that width for the access of 

 air. The pots were set in a trough of water, which by capillary attrac- 

 tion through the usual drainage hole kept their contents moist. Not- 

 withstanding these precautions against the introduction of cotemporary 

 seeds, the surface of the sbil was covered with a growth of moss com- 

 mencing next the sides of the pots, and later several ferns appeared. 

 But both mosses and ferns were of species common in the neigborhood 

 or in the green-house in which the pots stood, and their spores had 

 probably entered by the opening between the glass and the pot. A very 

 few phenerogams produced their seed leaves, but in spite of especial 

 care only a tender Galium developed flowers. 



Two similar trials were made with tertiary sand which gave the same 

 negative result. In September 1865, another parcel of the Loess was 

 obtained, and next spring spread 3 inches deep over zinc boxes 

 which were covered with glass shades whose edges were pressed into 

 the soil, and the whole covered with a glass case whose corners were 

 bound with zinc and covered with paper. Spring-water was poured on- 

 ly on the earth outside of the glass so that it must soak under the edge 

 thereof. Several such arrangements were prepared, some being placed 

 in a green house, others in the open air. Under these conditions the sur- 

 face of the soil was soon covered with a fine net of colorless mycelium 

 from which in July grew numerous small white fungi. There also ap- 

 peared either scattering or in masses, the common mosses, generally 

 commencing next the sides of the glass, showing that their spores were 

 introduced by the water. A few small ferns made their appearance 

 which probably entered the same way, and finally a single feeble spear 

 of grass spang up which was transplanted, and on flowering proved to 

 be Festuca pratensis The result of these experiments was entirely neg- 

 ative. The seeds which germinated were evidently of recent growth, 

 and their introduction easilv accounted for. Their occurrence un- 



