446 THE AMERICAN NATURALIST. (VoL. XXXIV. 
therefore, is governed “ by the varying balance of the meteorological 
conditions affecting the organisms." A table is given of twenty 
objects most commonly observed, showing the average date for each 
of the seven years. From these the normal date or phenochron of 
each species is computed, together with the phenological norm or 
phenochron of the entire list for each year. Other tables are given 
of objects selected from different counties and provinces. If ob- 
servers are symmetrically placed over a county, are competent and 
careful, and put the same interpretation on what constitutes “first 
appearance” and “becoming common,” the averages would give 
phenological norms for the comparison of a very important character 
of the country with that of another, and more especially the compari- 
son of one season with another in the same country, which, after a 
series of years, would contribute to the solution of the problem of 
secular variation of climate. 
In 1897 the idea was extensively taken up in the schools of Nova 
Scotia as a part of the prescribed course in nature study, the pupils 
themselves making the observations under the guidance of the 
teachers. Hundreds of reports were sent in from as many school 
districts. It is believed to be a convenient means for the stimulation 
of pupils in observing all natural phenomena while going to and 
from school. H C lum 
King's Irrigation and Drainage. — The high standard of excel- 
lence already established in the Rural Science Series under the 
editorship of Professor L. H. Bailey is fully maintained in the latest 
volume,’ Although this volume is quite complete in itself, it may be 
regarded, in a way, as supplementary to Professor King's work on 
soils, with which the series began. Like that, the present work is 
addressed primarily to practical farmers and agricultural students, but 
at the same time it contains much of value to all interested in the 
nutrition of plants. : 
In an introduction of sixty-five pages the author discusses with 
considerable fullness the importance of water to the plant, and 
details some noteworthy experiments carried on by him at the Uni- 
versity of Wisconsin to determine the quantity of water used by 
cultivated plants in coming to perfection under ordinary field con- 
ditions. The data thus obtained for various crops figure in impor- 
! King, F. H. 7rrigation and Drainage: principles and practice of their cul- 
tured phases. New York, The Macmillan Company, 1899.  12mo, xxii+ 502 pp» 
163 illustrations. 
