taat 
1885.] Botany. a, 
BOTANY.! 
THE Grasses OF Matne.—Under this title Professor Fernald, 
of the Maine State College, has brought out a neat pamphlet of 
* seventy pages and forty plates. It is designed for the use of 
4 
the author’s students, as well as for the farmers of the State. In 
the introduction is given a general description of the structure of 
grasses, with a pretty complete list of the technica) terms used in 
ordinary descriptive works, and acouple of pages on the composition 
of grasses. An analytical key precedes the descriptive portion of 
the book, the latter occupying about fifty pages. Common names 
and the pronunciation of the scientific names are given in 
every case. The descriptions are much simplified, and appear 
to be fairly accurate. Short notes upon their agricultural value 
follow each species. Eighty-one species belonging to thirty- 
eight genera are described, and of these forty-two species are 
figured in the plates borrowed from the department of agriculture 
at Washington. 
SPECTRUM OF CHLOROPHYLL.—When a ray of white 
light which has passed through a coloring-matter, for instance, a 
solution of one of the coal-tar dyes, red wine, or a solution of 
chlorophyll, is examined by means of a spectroscope, certain dark 
bands, known as absorption-bands, are observed at definite places 
in its spectrum. For convenience in examining the spectra of 
small amounts of coloring matters, a direct vision spectroscope 
attached to the tube of a microscope is employed, and the color- 
ing-matter in question is placed in a flat-walled bottle or a glass 
cell on the stage of the microscope. The ray of light which is 
reflected from the mirror under the stage passes first through the 
colored matter, next through the objective, and lastly through 
the prisms which compose the microspectroscopic attachment to 
the tube. 
In order to compare the spectra of different substances, a sec- 
ond prism or set of prisms is often used, by which the spectrum 
of a second liquid can be projected by the side of that of the first. 
The spectra of chlorophyll solutions from two different sources 
- can thus be at once compared. One of the combinations can 
also be employed to project the solar spectrum (unchanged by 
passing through any color whatever), and its constant lines 
(Fraunhofer’s lines) can be used for the determination of position 
of the bands seen in the spectrum of the liquid by its side. 
The spectra of many substances, among which chlorophyll oc- 
cupies a prominent place, have absorption-bands of such con- 
stancy in position and appearance that they are justly regarded 
-as characteristic. The spectrum of an alcoholic solution of 
chlorophyll has been shown to be essentially the same as that of 
the chlorophyll granule itself. In order, however, to obtain all 
1 Edited by PROFESSOR CHARLES E. BESSEY, Lincoln, Nebraska. * 
