Royale des Sciences, des Lettres et des Beaux Arts de Belgique. Collection in 8”, r8gg-rgoo, lix, third memoir, 56 pages.

Ia FENNER: Flora oder allgemeine botanischc Zeitrrng, 1904, xciii, 335-434 (especially pages 358-363).

I4 ABDERHALDEN and TERUCCHI : Zeitschrift fur physiologische Chemie. 1go6, xlix, 21-25.

” TISCHCTKIN : Bcrichte der deutschen botanischen Gesellschaft, 1889, vii, 346-355.

I0 TISCHUTKIN : Botanisches Centralblatt, 1892, 1, 304-305. ” DUBOIS: Comptes rerrdus des seances de l’Acadhmie des Sciences, 18go,

CXi, 315-317. “Duno~s: Comptes rendus dcs seances et mhmoirs dc la So&%! de Biologie,

1903, IV, 23a--233. y, COUVREUR: Comptes rendus des seances de l’dcademie des Sciences, rgoo,

cxxx, 8&8.$g. ao COUVREUR: Annales de la Socikte linnknne de Lyon, rgoo, Nouvelle serie,

xlvii, 81-83, published 1g01. a CLEMENT: Annales de la Socilte linnienne dc Lyon, 1915. Nouvelle skrie,

Ixii, 11-14, published IgI6. “ROBINSON: Torreya, I@, viii, 181-1g4. 18 HEPBURN : Proceedings of the American Philosophical Society, 1918, lvii,

I U-129. ” HEPBURN : Contributions from the Botanical Laboratory of the University

Of Pennsylvania, IgIg, iv, 442-451. ” HEPBURN and ST. JOHN : Contributions from the Botanical Laboratory of the

U?ziversity of Pennsylvania, IgIg, iv, 451-457. *'HEPBURN, ST. JOHN and JOKEI;: JOC’RNAL OF THE FRANI(LIX IXSTITL’TE,

1920, ClXXXiX, 147-184. ” DAKIN : Journal and Proceedings of the Royal Society of Western Australia,

rgr7-1918, iv, 37-53, published IgIg. w VOELCKER: Annals and kfagahe of Natural History, 1849, Series 2, iv,

128-136. 2o DARIVIN : Insectivorous Plants, 2nd Editiou, New York and London, Apple-

ton, IgI5, Chapter xiii, pp. 232~-260. II0 Official and Tentative Methods of Analysis of the Association of Official

Agricultural Chemists, Revised to November I, Igrg. Washington, Ig2o. 31 MACFARLANE: Contributions from the Botanical Laboratory of the University

of Pennsylvania, 1892, i, 7-44.

COXSTAXTINE HERIN~ LABORATORY, HAHNEMANN MEDICAL COLLEGE,

PHILADELPHIA, PA.

The Production of Nitric Oxides and Ozone by High Voltage Electric Discharges.-In Bulletin 9 recently issued by Purdue Uni- versity, KARL B. MCEACHRON and R. H. GEORGE give in much detail the results of experiments made at the University during the war and somewhat later, to determine conditions which promote the fixation of nitrogen with oxygen, a problem of great importance in industrial

CURRENT TOPICS. [;. F. I.

chemistry. It was found that methods for absorption of the gas could be devised which are much simpler than those heretofore in use, and that the amount of equipment was much less. Ozone was produced in almost all the experiments and the data in regard to it have been incjuded. The pamphlet covers 190 pages, including a good index and many diagrams and illustrations.

Some of the conclusions are as follows: Using fresh dry air on Siemens type of tubes, the application of a sufficiently high potential from either an induction coil or a high voltage transformer, will cause a decrease in pressure (the experiment being made with a closed volume of air) which shows a contraction of volume. After reaching a certain point, however, the action reverses, a result that had already been noted by Spiel.

I. Holding conditions as constant as possible the reversal points on check runs do not agree closely with respect to either time or reversal or the amount of pressure decrease. The yield of nitric acid is always much greater near the reversal point than after the pressure has increased up to the initial.

2. In case the air in the tube has been in contact for a considerable time with other air, even in minute quantities, which has been previously subjected to electrical discharge, the pressure decrease is modified or may be eliminated altogether, the pressure rising instead of falling. Such contamination decreases the yield and may under certain conditions prevent the formation of any absorbable products. The appearance of the discharge is greatly modified by such contamination.

3. It was found that the pressure decrease is not proportional to the nitric oxides absorbed. It has not been possible in most cases to account for more than a fractional part of the pressure decrease on the basis of the amount of ozone and nitric acid found. This seems to indicate the presence of some heavy molecule, which is not being absorbed.

4. As a rule the pressure did not decrease more than 60 mm. below the initial pressure, but in one case the decrease was 114 mm., the pressure characteristic being almost a straight line. It has not been possible to duplicate this run. The yield at a point near reversal was much le?s than that obtained from other runs with a decrease of pressure of not over 30 mm. When taking the probable temperature of the gas into account, the contraction in this run amounts to nearly one-fifth by volume.

5. Alternating current seems in most cases to cause a more rapid pressure decrease than does current from an induction coil having approximately the same effective value. This condition is most pro- nounced when the time of exposure is relativelv short.

H. 1,.