638 



SCIENCE 



[N. S. Vol. LIV. No. 1408. 



eight days preceding the aurora was 22.6 

 millimeters on my record; while for the five 

 days after the record became measurable the 

 mean diurnal variation was IY.7 millimeters. 

 During the entire month of June the electric 

 records were more than usually disturbed. 

 Early in July the disturbance increased. On 

 July 6, 7 and 8 the disturbances were the 

 greatest that have been observed since August 

 1, 1920. On the morning of July 10 an aurora 

 was reported as visible in northern California. 

 From that time to the present (July 19) the 

 records have been very little disturbed and 

 the range of variation has been much smaller 

 than the average for the year. 



Fernando Sanford 



THE AMERICAN CHEMICAL SOCIETY. 



(Continiwd) 



Increasing the yield of our dyes: J. L. Bullock. 

 The first consideration is a thorough knowledge of 

 the intermediates. Tests for quality are essential 

 as small amounts of impurity have a decided effect 

 on the yield. Specialization on few dyes is neces- 

 sary Ln order to know them thoroughly. The best 

 intermediates obtainable are usually the cheapest 

 in that they give greatly increased yields. The 

 sedimentation of solutions is advantageous and 

 filtration at every stage adds to tinctorial power of 

 the subsequent dye. In actual sjmthesis of dyes, 

 intelligent use of equipment is as essential as chem- 

 ical control. Uniformity in carrying out reactions 

 is a great factor in obtaining maximum yields. 

 Diazotizations should be as rapid as possible. Coup- 

 ling a difficult condensation; the foam a good indi- 

 cation of its course. It is important to precipitate 

 the dye in an easily filterable stat«. With tri- 

 phenylmethane dyes even greater care must be used 

 than with the azo dyes. A knowledge of the dye- 

 ing properties, fastness, etc., is very useful in get- 

 ting the standard of purity to the highest possible 

 point. Attention to the most minute details is 

 repaid by increased tinctorial power and lessened 

 cost of the finished dye. 



The preparation in the pure state of certain dyes 

 of the malachite green series: "Walter A. Jacobs 

 AND Michael Heidelberger. It is shown that in 

 many oases in which the chlorides are too soluble or 

 do not crystallize, the nitrates may advantageously 

 be used for isolation of the dyes. Descriptions are 

 given on this basis of salts of malachite green and 

 some of its methyl, halogen^ amino, acylamino, 



alkylamino, hydroxy, and alkoxy derivatives, as 

 well as the nitrate of brilliajit green, and the fur- 

 furol analog of malachite green. 



The electrometric titration of azo dyes: D. O. 

 Jones. The titanous chloride reduction methods 

 originally suggested by Knecht for the analysis of 

 numerous compounds, both organic and inorganic, 

 have, in recent years, come into more general use 

 in the field of dye chemistry. The titanous chloride 

 method for the analysis of azo dyes becomes more 

 generally applicable, when the end point of the 

 titration is determined by the electrometric method. 

 The method in general is similar to the usual oxidi- 

 metric analysis as carried out with the electrometric 

 apparatus. In the former methods, employing the 

 use of a sulphocyanide indicator, the end point in 

 the back titration with ferric alum is sometimes 

 difficult to determine. Dark colored material in 

 suspension and the color which is sometimes im- 

 parted to the solution by the products of reduction 

 do not interfere in the electrometric method. It 

 also permits the use of larger samples, while the 

 end point is readily and accurately obtained. 



Extraction process of wool degreasing : Louis A. 

 Olney. a thorough study of the subject of wool 

 cleansing is quit« sure to lead to the conclusion that 

 the extraction method, i.e., the treatment of the raw 

 wool under proper conditions with certain organic 

 solvents, is far more scientific in principle than the 

 ordinary emulsive process. With efficient apparatus 

 and good management the expense of cleansing 

 wool is reduced to a minimum by this process and 

 the results obtained approach the maximum estab- 

 lished through theoretical and economical considera- 

 tions. Although the early attempts to degrease 

 wool by the use of volatile solvents resulted in com- 

 plete failure, many practical incentives sufficed to 

 keep interest in- the process alive. 



Fastness to storage: Oscar E. Flynn. Dyed 

 cotton goods sometimes changes unevenly when 

 stored in the folded piece. Regions of change mark 

 out the channels along which air flows due to 

 changes in temperature. This shows that the 

 change in the dye is caused by some substance 

 present in the air in small quantity and not pri- 

 marily to oxidation, which shows its effect in the 

 interior of a mass of goods. In some eases the 

 change is temporary, and the result of the action 

 of acid alone. In other cases the effect is due in 

 the first place to acid, but followed later by com- 

 plete destruction of the dye. Alkali sensitive dyes 

 such as StUbene Yellow show temporary changes 

 due to acid alone. Acid sensitive dyes, such as 



