stars were shining brightly to the north. The moon, which was very low in the west (about 15° south of west, with an altitude of some 5° or 6°), was hidden from view by buildings, where I stood; and, because of the street lights, I was not even aware that the moon was out until the rainbow in the east caught my eye. None of the prismatic colors could be detected, the bow being merely a yellowish arch of light very well defined at the southern end-rather an odd thing to see at that time of night.

REED COLLEGE, PORTLAND, ORE.

FRANK L. GRIFFIN

SCIENTIFIC BOOKS

Gli Scienziati Italiani, dall'inizio del medio evo ai nostri giorni. Repertorio biobibliografico dei filosofii, matematici, astronomi, fisici, chimici, naturalisti, medici, e geografi Italiani. Diretto da ALDO MIELI, e compiuto con la collaborazione di numerosi scienziati, storici, e bibliografi. Vol. I., Parte I., Rome, 1921. Pp. viii+236. A. Nardecchia, publisher.

In the issue of SCIENCE of August 30, 1919, pp. 213-214, I called attention to Italian activity in the field of the history of science, evidenced by the new publication Archivio di Storia della Scienza, edited by Aldo Mieli, which journal has now completed its first year. The present work indicates the continued and growing interest in Italy in the history of science.

The first part of this biographical dictionary presents the biographies of thirty-three Italian scientists from the fifteenth to the present century. The list of contributors to the volume shows that the great scholars of Italy are devoting themselves to assure the success of the present work under the able editorship of the distinguished historian of science, Aldo Mieli.

One peculiarity of the work is that neither chronological nor alphabetical order of treatment is pursued in selecting the scientists included. Eventually, of course, the completed work will be provided with all necessary in

dices. Each volume includes also the alpl betical index of names.

The order of treatment of each biograp consists of the following: Life; Works, i cluding a critical discussion of the histori and scientific significance; Bibliography, i cluding complete catalogue of all works, wi place and date of printing of published wor editions, and translations with precise bibl graphical descriptions and also some sta ment of location in Italian libraries volumes mentioned; Literature, giving lists works which discuss the work or life of t scientist in question.

The mathematician will welcome the fi biographical statement (pp. 4-12) concerni Leonardo Fibonacci, written by Gino Lori the astronomer will appreciate the excelle account (pp. 45-67) of Schiaparelli, by El Millosevich; the geographer and the astron mer will find much of interest in the accou (pp. 101-111) of Giovanni Antonio Magi (1555-1617) by Antonio Favaro, who lists less than 47 printed works (and editions) Magini; the student of medical history, t botanist and naturalist and the physicist w enjoy a whole series of illuminating article Particularly noteworthy is the fact that photograph and a facsimile of handwritin is given of each scientist, wherever possib

This publication promises to be a wo comparable only to the English Dictionary National Biography; for America, France Germany there is no work of this natur When completed on present plans librari will find it as indispensable as the abo mentioned dictionary.

With the present state of exchange the pri of 45 liras for Part I., viii plus 236 pages, extremely low. Every effort should be ma by American scientists, historians, and brarians to encourage the continuation of th publication on the present scale. The effe tive way to do this is by subscription to t publisher, A. Nardecchia, Via dell' Universi 11-14, Rome, Italy.

The alphabetical list of articles follows: Acri, Francesco (1834-1913), philosopher, E. P. Lamanna.

An Einstein four-dimensional manifold, defining a permanent gravitational field, can never be regarded as immersed in a flat space of five dimensions.

This applies in particular to the solar field (defined say by the Schwarzschild form), in which the earth and the other planets are moving. The appropriate value of n must therefore be greater than 5 and less than 11. A brief discussion shows that actually n=6. Therefore:

The solar gravitational field can be represented by a curved manifold of four dimensions situated in a flat space of six dimensions.

This manifold can be written in finite form and gives what may be called a geometric model of the field in which we are living.

The proofs of these theorems and the actual equation of this model are appearing in current numbers of the American Journal of Mathematics, together with the full discussion of the general results connecting light rays. and orbits in any field stated in SCIENCE, October 29, 1920, pp. 413-414.

COLUMBIA UNIVERSITY

EDWARD KASNER

THE AMERICAN CHEMICAL SOCIETY

(Continued)

FERTILIZER DIVISION

F. B. Carpenter, chairman
H. C. Moore, secretary

Kelp as a basis of an American potash industry: J. W. TURRENTINE.

Relationships of chemistry and the fertilizer industry: C. H. MACDOWELL.

A perfect fertilizer law: E. G. PROULX. Boron in relation to the fertilizer industry: J. E. BRECKENRIDGE.

The quantitative estimation of borax in mixed fertilizers: J. M. BARTLETT.

Note on the determination of nitrogen in fertilizers containing both organic and nitric nitrogen: F. B. CARPENTER. Notwithstanding the fact that the modified Kjeldahl and Gunning methods have been in use for a number of years, the results obtained by these methods in the hands of different analysts on samples containing mixtures of organic and nitric nitrogen are far from satisfactory.

23

This is probably largely due to a wrong interpre tation of the official method. From the standpoin of the manufacturer this is quite a serious matte and it seems desirable that the Association of Off cial Agricultural Chemists should take such actio as is necessary to modify or at least change th reading of the modified methods so that there ma be no misunderstanding of how they should b carried out.

Thi

Dicyanodiamide. A rapid, direct method for it determination in cyanamid and mixed fertilizers ROLLA N. HARGER, presented by Oswald Schreiner The method depends upon the fact that when a so lution of silver picrate is added to a solution o dicyanodiamide, the latter is quantitatively precipi tated as a double compound of silver picrate and dicyanodiamide, CH2 (NO2),OAG, C2H.N.. new double compound we have named silver picrate mono-cyanoguanidine. It forms in small crystal which quickly settle out of the solution and can be separated upon a Gooch crucible very rapidly, s that the analysis can be carried out in a very short time. Neither cyanide nor urea give any precipitate when their solutions are treated with silver picrate and determinations of dicyanodiamide carried out in the presence of these compounds showed that they have no effect upon the analysis. The molar weight of the compound is 420.22, five (4.991) times that of dicyanodiamide, a fact which greatly enhances the accuracy of the method, since an error of 1 mg. in the precipitate weighed will mean an error of only 0.2 mg. of dicyanodiamide or 0.13 + mg. of nitrogen.

The changes taking place in cyanamid when used in mixed fertilizers: ROLLA N. HARGER, presented by Oswald Schreiner. (1) When cyanamid is placed in a mixed fertilizer containing acid phosphate and 5-10 per cent. of moisture, the cyana mide content decreases with great rapidity. (2) This change is represented principally by, and in many cases quantitatively by, the formation of dicyanodiamide. (3) A given quantity of moist acid phosphate is able to transform a limited amount of calcium cyanamid. (4) Cyanamid is not affected by dry acid phosphate. (5) Moisture alone is able to cause the conversion of cyanamid to dicyanodiamid, but the change is much slower than when acid phosphate is present. Since it has been repeatedly shown that dicyanodiamid is valueless as a fertilizer material and, moreover, is toxic to many plants, the formation of this com pound in fertilizer materials seems undesirable. From the results of this study it would seem that

the method of applying cyanamid, commonly employed, which consists in adding the cyanamid to fertilizer mixtures containing acid phosphate, which mixtures almost always contain several per cent. of moisture, is a very questionable practise. Moreover, the use of cyanamid as a "conditioner'' for "green" acid phosphate is very probably at the expense of most of the nitrogen in the cyanamid. On first thought it would appear that this conversion of cyanamid into dicyanodiamide could be avoided by simply employing dry fertilizer mixtures, but this overlooks the fact that when such mixtures are added to the soil moisture conditions are at once provided and the transformation may possibly then take place. Preliminary experiments carried out in this laboratory indicate that under certain conditions at least this is the case.

Some results of the determination of potash by the Lindo-Gladding method, using alcohol of various strengths in the presence of sodium salts: R. D. CALDWELL and H. C. MOORE. When potash is determined by the official method of the A. O, A. C. but slightly lower results are obtained when 80 per cent. alcohol is used than when 92 or 95 per cent, is used in case of sample of pure potassium chloride, but when sodium chloride or sulfate is added the results with 80 per cent. alcohol are lower. Tests with a sample of potassium platinic chloride showed it to be but slightly soluble in 80 per cent. alcohol alone, but the solubility increases with the increase of sodium salts added but with 95 per cent. alcohol sodium salts have no effect.

Injurious effects of borax on field crops: F. B. CARPENTER. It has long been known that certain chemical substances are poisonous to plant life. While certain compounds of copper, zinc and arsenic are exceedingly poisonous, compounds of manganese and boron are far less deleterious. Most of the experiments which have been made with these compounds have been made on plants grown in pots or water cultures; in case of borax, however, considerable knowledge has been gained during the past few years on field crops from the use of Searles Lake potash, which contained an excessive amount of this compound. The first large scale borax poisoning in this country occurred in Indiana in 1917 on corn. In 1919 considerable damage was reported on potatoes and tobacco in different localities. Many conflicting reports were made in regard to amount of borax required to produce injury. While in some instances as little as two pounds per acre has been reported to have slightly injurious effects, one report was noted

where as much as 400 pounds with apparently no bad results. by the writer on corn, beans, co sweet potatoes and tobacco sh where 8 pounds anhydrous b used, but there was slight i pounds. It is evident, therefor of soil, amount and time of of application, etc., influence t amount of borax which can be ous effect.

The "blank" in the Kjeldah ical and commercial significanc

Potash shales of Illinois: M W. PARR. (1) Shales occur in a in Illinois which contain five potash. (2) Shale outcroppin near Jonesboro in Union Co five per cent. of potash would b can be determined from its c and physical character, for use of Portland cement. (3) By u the manufacture of cement a known methods of potash reco pounds of potash, representing cents per barrel of cement coul The constitution of the south complex. The shale contains matter, pyrite, undecomposed rock, feldspathic in character ing material of the nature of sand. (5) Shale from Dixon,] 5.8 per cent. of potash which part in a more stable conditi southern Illinois shale. (6) F tassium from shale of either or Dixon type by means of sol would seem to be impracticabl complete reaction of these re and because of the cost of lea potash from material where i small amounts. (7) The plar potash in the southern Illino characteristic of all of the n outcropping in that locality. the potassium in the southern is soluble in sulphuric acid, combination of the glauconite ern Illinois shale having a p per cent. in the raw condition ignited, 62 per cent. of the conitic in character and is av

Potash situation in Germar

Reports.

RUBBER DIVISION

W. K. Lewis, chairman Arnold H. Smith, secretary

Discussion: Shall the Rubber Division publish an annual volume of reprints and lengthy abstracts of everything of interest to the rubber chemist made public during the year?

Election of officers.

Rubber energy: W. B. WIEGAND. (Lantern.) The aging of some rubber compounds: New Jersey Zinc Co. Research Laboratories. (Lantern.)

Some microsections cut from vulcanized rubber articles: New Jersey Zinc Co. Research Laboratories. (Lantern.)

In a

The action of certain organic accelerators in the vulcanization of rubber. II.: G. D. KRATZ, A. H. FLOWER and B. J. SHAPIRO. The relative activities of molecularly equivalent amounts of aniline and diphenylthiourea in the acceleration of vulcanization were compared in rubber-sulfur mixtures and in mixtures which contained zinc oxide. rubber-sulfur mixture the activity of aniline was found to be much greater than that of diphenylthiourea. In mixtures which contained zinc oxide, the reverse was true. With aniline as the accelerator, either in the presence or absence of zinc oxide, the same maximum tensile strength was obtained, accompanied by a higher sulfur coefficient in the absence of zinc oxide than when this substance was present. The mixtures which contained zinc oxide, attained the same maximum tensile strengths at approximately the same sulfur coefficients, irrespective of whether aniline or diphenylthiourea was employed as the accelerator. It is evident that there is apparently no general relation between the physical properties and sulfur coefficients of accelerated mixtures.

The action of certain organic accelerators in the vulcanization of rubber. (II.): G. D. Kratz, A. H. FLOWER and B. J. SHAPIRO. The activities of certain synthetic, nitrogenous organic accelerators, in a mixture of rubber and sulfur, were compared with the dissociation constants of the original substances. With the exception of members of a closely related series, no definite relation was found to exist between the activities of the substances as accelerators and their dissociation constants. Substances which decompose, or react, with other components of the mixture to form substances of acid character do not accelerate unless a neutralizing base, or salt, is present. The re

sults obtained, and the conclusions drawn fro them, compare favorably with other results o tained with ammonium salts.

Method for the determination of free sulfur a antimony tri- and penta-sulfides in golden an mony: J. F. SCHUFTER.

The action of heat and light on vulcanized ru ber: J. B. TUTTLE. The action of heat and lig on vulcanized rubber is frequently spoken of being identical and oxidation is said to be t cause of the deterioration. From published a unpublished tests it is shown that the action heat is one of change in the rate of the chemic reaction between rubber and sulfur and goes throughout the entire mass, whereas the action light is one of oxidation, taking place on the su face. Heat produces no change in the solubili of the rubber substance in solvents such as aceto and alcohol, whereas light breaks up the rubb molecule forming decomposition products whi are readily soluble in acetone.

A theory of vulcanization based on the form tion of polysulphides during vulcanization: WI FIELD SCOTT and C. W. BEDFORD. All organic a celerators and a number of inorganic accelerato function as catalysts of vulcanization through t formation of polysulphides. These accelerato may be placed into two classes: (1) Hydrog sulphide polysulphide accelerators. Organic bas are believed to form polysulphides by the aid hydrogen sulphide. Examples are piperidene an dimethylamine which form polysulphides in t presence of hydrogen sulphide and sulphur. Ind ganic bases, such as sodium hydroxide, calcium h drate, magnesium oxide and basic magnesium ca bonate, function in the same manner as the abov (2) Carbo-sulph-hydrol polysulphide accelerato Thio ureas and dithiocarbamates are believed form some type of polysulphides through t grouping C-SH. Differentiated from the abo two classes of accelerators are such accelerators zinc oxide and litharge which do not form pol sulphides. These are termed "secondary accel rators' owing to the fact that they decompo polysulphides to give active sulphur.

DIVISION OF WATER, SEWAGE AND SANITATION J. W. Ellms, chairman W. W. Skinner, secretary Water softening for the manufacture of ro water ice: A. S. BEHRMAN. The manufacture