FRAGMEXTS OF SCIENCE. 



569 



I can now trace in any of the ' themes ' of 

 which Prof. Channing thought so well. There 

 is no greater mark of the progress of the 

 university than the expansion of the electives 

 to include the natural sciences. .My own 

 omnivoroupness in study was so great that I 

 did not suffer much from our restricted cur- 

 riculum ; but there were young men in my 

 time who would have graduated in these 

 later days with highest honors in some de- 

 partment of physics or biology, but who 

 were then at the very foot of the class, and 

 lost for life the advantage of early training 

 in the studies they loved. Akin to this mod- 

 ern gain and equally unquestionable is the 

 advantage now enjoyed in the way of original 

 research. Every year young men of my ac- 

 quaintance come to me for consultation about 

 some thesis they are preparing in history or 

 literature, and they little know the envy with 

 which they inspire their adviser; that they 

 should be spared from the old routine to in- 

 vestigate anything for themselves seems such 

 a happiness." 



Forests and Riyer Flow. Mr. C. C. 



Vermeule observes, in a report of the State 

 Geological Survey on Forestry in New Jersey, 

 that in estimating the relation of forests to 

 the flow of rivers we should not consider the 

 points of extremely high and extremely low 

 water, but should look for the beneficial 

 effects in the stages which prevail during the 

 months of an ordinary dry period. " The 

 soil and subsoil of a watershed," he says, 

 " hold a large amount of water, which is fed 

 out as drainage, in the form of springs and 

 seepage, to the stream during dry periods. 

 It is a matter of common observation that 

 at such times rivers continue to flow when 

 the rainfall is much less than the evapora- 

 tion, and indeed for long periods when there 

 is no rainfall at all. Anything which tends 

 to increase the amount of water which is 

 held in the ground, and to regulate its dis- 

 charge into the streams, tends to give a 

 larger flow, and to shorten the periods of 

 very low water in the streams during 

 droughts, and with this increased capacity 

 of the ground to absorb rain come also less 

 frequent floods. Humus in the forest forms 

 a great sponge, and of itself holds a large 

 amount of water, while it and the inequali- 

 ties caused by tree roots, etc., tend to pre- 



vent the water flowing over the surface, and 

 the roots of the trees provide channels by 

 which the water percolates into the subsoil 

 readily. In this way the forest will easily 

 absorb a larger amount of water than open 

 lands. A high state of cultivation also has 

 a tendency to increase the capacity of the 

 ground to absorb water, because of constant 

 loosening of the surface and the facilities 

 provided for ready drainage. In this way 

 cultivation, like forests, tends to render 

 floods less frequent, but the effect of the 

 drainage of the soil is that the ground water 

 absorbed is fed out more rapidly to the 

 streams during the early months of a dry 

 period than is the case in forests ; conse- 

 quently the ground water is sooner exhausted 

 and the duration of the low stages of the 

 rivers during protracted droughts is thereby 

 lengthened. Barren watersheds offer lesa 

 capacity for absorption of rainfall. There is 

 no humus or other matter on the surface to 

 retain the rain, and the ground becomes hard 

 and resists free percolation." 



Long-Jived Seeds. M. Casimir de Can- 

 dolle said, in an account in the British As- 

 sociation of experiments dealing with latent 

 life in seeds, that seeds retain their germi- 

 nating faculty for very long periods of time 

 if kept dry and protected from all external 

 influences which would produce changes in 

 their physiological condition. The question 

 as to what is their physiological condition 

 during the period of rest is an interesting 

 one. It is possible to conceive them as ab- 

 sorbing oxygen or as giving off carbonic di- 

 oxide. If the latter process takes place, the 

 carbon must be supplied from the tissues of 

 the seed itself. In that case would the seed- 

 lings produced from these seeds be normal ? 

 The author had raised perfect seedlings from 

 seeds known to have been kept more than a 

 hundred years. A remarkable instance of 

 the length of time seeds may be preserved 

 was afforded where, on clearing away heaps 

 of rubbish which had been undisturbed for 

 a long time in a silver mine m Greece, the 

 ground over which the heap had lain became 

 in a short time covered with a mass of 

 plants, of which the seeds from which they 

 sprang could not have been thei'e less than 

 fifteen hundred years. An Irish agricultur- 

 ist in the audience said that certain fields 



