October 11, 1907] 



SCIENCE 



4St 



of influencing conditions, their relative im- 

 portance in producing the common effect is 

 not easy to determine. 



Evidently, since the temperature is nearly 

 always lower at night than during the day- 

 time, the upper layer of the soil thus cooled is 

 usually damper in the early morning than in 

 the afternoon; and whenever the temperature 

 falls very greatly, the corresponding large in- 

 crease in the tension and in the condensation 

 at the cold surface will take much moisture 

 from the warmer soil beneath. It is largely, 

 if not wholly, this that leads to wet soils so 

 often seen on cold mornings when there has 

 been no rain, and to the surprising depth of 

 mud that frequently follows a thaw. It ac- 

 counts too for the considerable supply of mois- 

 ture from the deeper soil in the production of 

 ice columns — spewing of the ground. 



This temperature effect on surface tension, 

 on condensation and on evaporation also 

 greatly conserves that moisture already in the 

 earth and keeps it in motion. That is, the 

 moisture is brought to the surface in gTeatest 

 abundance only when the temperature there is 

 low and therefore the rate of evaporation into 

 the air small; and whenever the surface tem- 

 perature is increased, leading to a higher rate 

 of evaporation into the air, the moisture is 

 drawn away to the colder portions of the soil 

 beneath, where it is protected from the winds 

 by the top layers which it has just left. 



W. J. Humphreys 

 Mount Weather Obseevatory, 

 Bluemont, Va. 



BOTANICAL NOTES 

 a new edition of englee's syllabus 

 The fifth edition of Engler's " Syllabus der 

 Pflanzenfamilien " (Borntraeger, Berlin) 

 which appeared during the present year, 

 differs very little from the fourth (1904). A 

 few slight changes are made here and there, 

 but the book is essentially unchanged. Yet it 

 has been reprinted from beginning to end, 

 illustrating afresh the fact that in book pub- 

 lishing the Germans do things better than we. 

 Had this book been published in this country 



the first edition would have been electrotsTped, 

 and it is safe to say that this fact would havfr 

 made it impossible for us to have had four 

 subsequent editions in the short time which 

 has elapsed since the appearance of the first. 

 The electrotyping of a scientific book ought 

 not to be permitted, for it always means that 

 the publisher proposes to keep it in essentially 

 its present form for as long a time as possible. 

 Why should not American botanists insist that- 

 their publishers shall not electrotype their 

 books, and that the editions be of a limited 

 number of copies ? We ought not to be tied to 

 our dead and disowned ideas merely because 

 our publishers prefer to embalm them by 

 electrotyping. 



Another suggestion which comes to one who 

 examines this book is that the term " Thallo- 

 phyta " is passing. It has long stood as an. 

 omnibus term to cover many different groups 

 of plants. In the third edition (1903) the- 

 term was abandoned, and in its place appeared 

 eleven coordinate terms, which were reduced 

 to ten in the fourth and fifth editions. One 

 looks in vain for this time-honored name for 

 the lower plants. It has apparently gone to 

 the limbo to which have been banished 

 " cryptogam " and " phenogam." The Vege- 

 table Kingdom is now divided into twelve 

 grand divisions or phyla, namely; Phytosar- 

 codina, Schizophyta, Flagellata, Dinoflagel- 

 latcij Zygophyceae, Chlorophyceae, Charales, 

 Phaeophyceae, Rhodophyceae, Eumyceies (all- 

 of which formerly were lumped together as 

 " Thallophyta "), Emhryopliyta asiphonogama 

 (Bryophyta, and Pteridophyia) , and Emhryo- 

 pliyta, siphonogama (Spermatophyta). And" 

 yet we shall doubtless have the text-books 

 speaking about " Thallophyta " for years to 

 come, as though the group had not been long 

 since abandoned. 



A NEW laboratory MANUAL 



An interesting and no doubt useful labora- 

 tory manual is Miiller's " Mikroskopisches und 

 Physiologisches PraktUvmn der Botanik fiir 

 Lehrer" (Teubner, Leipzig), a little book of 

 240 pages and 235 text illustrations. Twenty 

 pages are given to the microscope and micro— 



