272 
SCIENCE. 
BOOKS RECEIVED. 
Methods and Results. — Description of an im- 
proved Vertical Clamp for the Telescopes of the The- 
odolites and Meridian Instruments — United States 
Coast and Geodetic Survey — Appendix No. 13 — 
Report for 1877 — Washington Government Printing 
Office, 1880 : 
The advantages of this improvement, which has been 
devised by Mr. George Davidson, an assistant of the 
United States Coast Survey, may be briefly stated as fol- 
lows : 
I. The telescope is clamped with sufficient firmness 
to admit ot its being moved in altitude in the vertical 
plane by the slow-moticn screw. 
II. The clamp maybe made to hold the transit-axis so 
gently that a very delicate tap on the telescope will bring 
the latter to the desired elevation. 
III. The top of the clamp is open, so that it permits 
the telescope to be lifted out for reversal and readily 
replaced in the Y’s without carrying the clamp with 
it. 
IV. The jaws of the open clamp remain during reversal 
in the same position as when unclamped before the re- 
versal of the telescope. 
V. There is no tendency to lift the vertical plate 
through eccentricity of the slow-motion screw, and con- 
sequently no resultant movement of the transit axis in 
azimuth. 
We advise those who would like to know more of 
this improved clamp to address directly to Mr. Davidson, 
whose address is United States Coast and Geodetic 
Survey, San Francisco, Cal. 
Manual of the Vertebrates of the Northern 
United States. By David Starr Jordan, 
Ph. D„ M. D„ Professor of Natural History in In- 
diana University, 3d Edition. Revised and Enlarged. 
Jansen, McClurg & Company, Chicago, 1880. 
This book, which was originally written to afford col- 
lectors and students who were nit specialists, a ready 
guide for identifying the families, genera and species 
of our vertebrate animals, is now again presented to the 
public in a third edition, which would appear to indicate 
that the work meets a demand made by Naturalists, and 
has been received with approval. 
This is a purely technical work, the author confining 
himself strictly to details necessary to be understood 
for scientific classifications, while signs and abbreviations 
are freely used to reduce the matter to its lowest limits. 
The author has been assisted by such eminent natural- 
ists as Dr. Elliott Coues, Professor E. D. Cope, Dr. 
Theodore Gill, Professor H. E. Copeland, Mr. E. W. 
Nelson, Mr. B. H. Van Vleck, Mr. C. H. Gilbert and 
Dr. A. W. Brayton, and efforts have been made to in- 
clude in this edition the results of recent investigations 
in this department of scientific research. 
The ground covered by this work includes the district 
east of the Mississippi river, and north of Carolina and 
Tennessee, exclusive of marine species. 
The work concludes with a good glossary of the prin- 
cipal technical terms used in the book, a glossary ot spe- 
cific names, and also an index to names of genera and 
higher groups with their derivattions. 
This manual of the vertebrates will prove valuable, not 
only to students, but to the large class of amateurs who 
desire to classify the forms included in this work. 
The Electric Laryngoscope, by A. Wellington 
Adams, M.D. jReprint from the Archives of La- 
ryngology, Sept. 1880.] 
We are once more reminded, by this little pamphlet, of the 
manifold applications of the electric light in the practical 
departments of medicine and surgery. Dr. Adams claims | 
for the instrument he has devised, the following advan- 
tages : 1. The application of what is the nearest approach 
to sunlight — the electric light— in such away as to bring 
it under perfect subjection and be readily manipulated. 
2. The establishment of a permanent relationship between 
the source of light and the throat mirror. 3. The use of 
a light which emits neither gas nor heat, and is of such 
concentration and intensity as to illuminate the respira- 
tory tract down to a point nearly an inch below the “ bi- 
furcation,” so that every detail in the larynx and trachea 
down to that point is sharply defined in the throat 
mirror, and if the latter be large and slightly concaved, 
any particular detail requiring special structural examin- 
ation may thus be greatly magnified. 
The Variations of the Fixed Points of Mercurial 
Thermometers, and the Means of Recognizing them in 
the Determination of Temperatures. — J. Pernet agrees 
with M. Crafts that the part played by pressure in the per- 
manent elevation of the zero-point is very trifling, if it exist 
at all. 
Boro-deci-tungstic Acid and its Sodium Salts. — Ac- 
cording to D. Klein, if tungstic acid in excess is dissolved 
in a boiling solution of borax with twice its molecular weight 
of boric acid (crystalline), the ebullition kept up for some 
hours, the undissolved tungstic hydrate filtered off the re- 
sulting solution deposits crystals of boric acid and sodium 
polyborates. The mother-liquor, if concentrated and 
placed- in a vacuum, deposits first borax and then the ex- 
ceedingly soluble sodium salt of the new acid, containing 
2 mols. of constitutional water. 
Appearance of Ozone on the Evaporation of Vari- 
ous Liquids as a Lecture Experiment. — R. Bottger recom- 
mends to moisten a piece of paper uniformly with starch 
containing cadmium iodide, to let fall upon it a few drops 
of alcohol or ether, and to set the latter liquid on fire. 
After its evaporation the paper is found turned decidedly 
blue in consequence of the formation of ozone. — Pol. Notiz- 
blatt , 35, 95. 
Singular Behavior of Stannous Chloride with Po- 
tassium Chlorate. — R. Bottger states that if 2 parts of stan- 
nous chloride and 1 part potassium chlorate, both previously 
pulverized, are rubbed together in a porcelain mortar, the 
mixture becomes very hot, chlorous acid and watery vapor 
are evolved, and there remains a yellowish white mass, 
which, if dissolved in boiling water, deposits potassium 
perchlorate in micaceous crystals. The mother-liquor con- 
tains tin oxychloride. 
Hypochlorine and the Conditions of its Origin in 
Plants. — M. Pringsheim has demonstrated the existence 
of a body in the green cells of plants, which he named hy- 
pochlorine on account of its relation to chlorophyll. He 
has quite recently described, in a paper, its occurrence and 
its microchemical characters. 
Chlorides of Camphor. — The products which arise on 
the action of phosphorus pentachloride upon camphor are 
affected by the quantity of the phosphorus chloride present 
and by the temperature.- If every increase of temperature 
is prevented no hydrochloric acid appears, and there is 
formed a homogeneous camphor dichloride in theoretical 
quantities. Pfaundler’s dichloride, and the body melting 
at 6o° and described as monochloride, are probably merely 
mixtures. F. V. Spitzer — Wien. Anzeiger, 1880, 71. 
Decomposition of Simple Organic Compounds by Zinc- 
dust. — The higher alcohols from ethylic alcohol upwards, 
on distillation over zinc-powder which was heated to 330°, 
to 350°, were decomposed into the corresponding olefine 
and hydrogen. Under the same circumstances methylic 
alcohol is resolued into carbonic oxide and hydrogen. 
Hans Jahn. — Wiener Anzeiger, 1880, 73-74. 
New Syntiiesisof Dimethyl-acrylic Acid. — Thiscom- 
pound is formed along with ethjdisoxy-valerianic acid when 
brom-iso-valerianic ether is brought in contact with sodium 
ethylate in absolute alcohol. E. Duvillier. — Ann. Chim. 
Phys., 19, 429. 
