“ The Romance of the Heavens. 
_*-man by RUDOLF ROSENSLACK. 
May 3, 1901.] 
BOOKS RECEIVED. 
G. BIGOUR- 
Pp. vi+ 
Le systéme métrique des poids et mesures. 
DAN. Paris, Gauthier Villars. 1901. 
458. 10 fr. 
< A Treatise on Electro-magnetic Phenomena and on the 
Compass and its Deviations. COMMANDER T. A. 
Lyons. New York, John Wiley & Sons ; London, 
Chapman & Hall, Limited. 1901. Pp. xv + 556. 
Phycomyceten and Ascomyceten. ALFRED MOLLER. 
Jena, Gustav Fischer. 1901. Pp. xii+ 318 and 
11 plates. Mk. 24. 
Elementary Questions in Electricity and Magnetism. 
- MAGnus MACLEAN and E. W. MarcHant. Lon- 
» don, New York and Bombay, Longmans, Green & 
~Co. 1900. Pp. 59. 
A. W. BICKERTON. 
New York, The Macmillan Co.; London, Swan, 
Sonnenschein & Co., Limited. 1901. Pp. iii+ 
284. $1.25. 
Teut-book of Zoology, treated from a Biological Stand- 
point. Otro ScHMEIL. Translated from the Ger- 
Edited by J. T. 
CUNNINGHAM. New York, The Macmillan Co.; 
London, Adams and Charles Black. 1901. Pp. 
xvi-+ 493. $4.00. 
Diseases in Plants. H. MARSHALL WARD. London 
» and New York, The Macmillan Co. 1901. Pp. 
xiv-+ 309. $1.60. 
SCIENTIFIC JOURNALS AND ARTICLES. 
Tue Botanical Gazette for April contains fur- 
ther descriptions of new species of North 
American trees by Professor C. S. Sargent. 
Among them are thirteen species of Crataegus, 
which is proving to be one of the most prolific 
of our genera in species, a new Betula from 
Alaska, and a new Cupressus from California. 
Professor C. O. Townsend writes upon the effect 
of hydrocyanic acid gas upon grains and seeds. 
Since this gas has become extensively used for 
fumigating purposes, it has become important to 
determine its effect upon the germination of 
seeds and upon their use as food. Professor 
Townsend has demonstrated that if the grain 
and seeds are dry the influence of the gas upon 
the vitality is far less marked than if they are 
moist. Dry seeds treated with the gas are not 
injured for food, but damp seeds should not be 
used until several hours after removal from the 
gas. Mr. A. C. Life contributes an interesting 
study upon the tuber-like rootlets of Cycas revo- 
SCIENCE. 
709 
luta, in which the rdle played by the fungi and 
by the algae upon the formation of these tuber- 
cles is worked out. Mr. Newton B. Pierce de- 
scribes a new bacteriosis of the walnut which 
has become a well-marked disease in California. 
The active organism proves to be a new species 
of Pseudomonas. The usual book reviews, 
minor notices and notes for students complete 
the number. 
THE second (April) number of Volume II. of 
the Transactions of the American Mathematical 
Society contains the following papers: ‘Ca- 
nonical Forms of Quaternary Abelian Substitu- 
tions in an Arbitrary Galois Field,’ by L. E. 
Dickson; ‘Certain Cases in which the Vanish- 
ing of the Wronskian is a Sufficient Condition 
for Linear Dependence,’ by M. Bécher; ‘An 
Elementary Proof of a Theorem of Sturm,’ by 
M. Bocher ; ‘On the Determination of Surfaces 
capable of Conformal Representation upon a 
Plane in such a Manner that Geodetic Lines are 
represented by Algebraic Curves,’ by H. F. 
Stecker; ‘On the Existence of a Minimum of 
Integral {2G y, y/) dx when a and a, are 
Conjugate Points, and the Geodesics on an El- 
lipsoid of Revolution ; a Revision of a Theorem 
of Kneser’s,’ by W. F. Osgood; ‘On the 
Geometry of Planes in a Parabolic Space of 
Four Dimensions,’ by I. Stringham. 
THE March number of the Bulletin of the 
American Mathematical Society contains the 
following papers: ‘Report of the December 
Meeting of the Chicago Section,’ by Professor 
T. F. Holgate; ‘Indirect Circular Transforma- 
tions and Mixed Groups,’ by Professor H. B. 
Newson; ‘Pyre Mathematics for Engineering 
Students,’ ey Professor A. S. Hathaway; ‘ Re- 
view of Adams’ Unpublished Papers,’ by Pro- 
fessor E. W. Brown; ‘Notice sur M. Hermite’ 
(translation of an address before the Paris 
Academy of Sciences), by M. C. Jordan; 
‘Notes’; ‘New Publications.” The April num- 
ber contains the following papers: ‘ Report of 
the February Meeting of the Society,’ by Pro- 
fessor F. N. Cole ; ‘Green’s Functions in Space 
of One Dimension,’ by Professor M. Bocher ; 
‘On aSystem of Plane Curves having Factorable 
Parallels,’ by Dr. Virgil Snyder; ‘ Possible 
