September 5, 1907] 



NA TURE 



483 



chemical reagents. When decomposed it always gives rise 

 to ferrous salts. On exposure to light it yields carbon 

 monoxide and an orange crystalline solid— diferronona- 

 carbonyl, Fe,(CO),. This, when heated alone, gives a 

 dark green liquid consisting chiefly of iron penlacarbonyl, 

 but when hydrocarbons or ether are present in excess and 

 the temperature is maintained below 100° C, an intensely 

 green-coloured solution is obtained, which deposits dark 

 green lustrous crystals of iron tetraearbonyl, Fc(CO),. 

 This is stable towards reagents, and its dark green 

 solution in organic solvents exhibits a characteristic 

 absorption band in the yellow. 



Dr. K. S. Caldwell described his investigations on the 

 conductivity of electrolytes in pyridine carried out in 

 Leipzig in Prof. Hantzsch's laboratory. With the excep- 

 tion of the pyridonium halides, the true acids, compared 

 among themselves, follow approximately the same order 

 in pyridine as in water, and the same applies to the 

 pseudo-acids, which, however, yield much better conduct- 

 ing solutions than do true acids having the same or even 

 greater affinity constants. He further dealt with the in- 

 fluence of temperature on the conductivity of electrolytes 

 in pyridine solution. The temperature of maximum con- 

 ductivity is well marked, but it is not higher the greater 

 the conductivity as in the case of solutions in liquid 

 sulphur dioxide. Pyridonium salts in pyridine show an 

 abnormally high conductivitv. 



On Monday Dr. Alex. McKenzie presented a valuable 

 report on the applications of Grignard's interaction. Since 

 the discovery in igoo that a vigorous action ensues when 

 magnesium powder is added to a mixture of methyl iodide 

 and anhydrous ether, and that this product is extremely 

 active, the Grignard method has been applied with 

 important results in almost every branch of organic 

 chemistry, and the progress made with its help in so short 

 a time as six years is little short of amazing. 



By means of it, secondary alcohols are obtained from 

 aldehydes, tertiary alcohols from ketones, acid chlorides 

 or acid anhydrides. Unsaturated hydrocarbons are also 

 obtained from aldehydes, ketones, &c., under suitable con- 

 ditions. It is also applicable to the preparation of 

 carboxylic, sulphinic and other sulphur acids, of ketones, 

 aldehydes, ethers and esters, and also of alkyl and aryl 

 metallic compounds. Dr. McKenzie dealt at length with 

 the preparation of the agent, and this part of the report 

 should prove of the utmost value to future workers in this 

 field. 



Prof. Tschitschibabin, of Moscow, read a valuable paper 

 on triphenylmethyl, in which he discussed the formula 

 of this remarkable substance. Dr. Chattaway described 

 his copper mirrors discovered in the course of an investi- 

 gation on the oxidation of aromatic hydrazines. When 

 solutions of cupric salts are reduced by these compounds 

 the metal is deposited on the glass in the form of a 

 brilliant coherent film. h. number of such mirrors were 

 exhibited ; they showed the lustrous red colour of burnished 

 copper, and were perfect in reflecting surface and 

 uniformity. Dr. Boudouard contributed an account in 

 French of the suboxides of carbon. 



Dr. Jaeger, of Amsterdam, described the colour changes 

 which occur on melting cholesterol esters, and dealt with 

 the theory of these from the point of view of the phase 

 rule. The colours are due to the formation of doubly 

 refracting layers of liquid crystals and occur at, or a few 

 degrees below, the transition temperatures whilst the two 

 liquid layers are separating from each other. The author 

 gave a striking demonstration of these liquid crystals. 



Prof. Phillips Bedson described and exhibited an 

 apparatus for studying the inflammability of mixtures of 

 coal dust and air, consisting of an arrangement whereby 

 the dust was projected by a blast of air through a gap 

 between two platinum wires, and there subjected to a 

 series of electric sparks. A number of interesting experi- 

 ments were shown with this apparatus ; in one instance 

 the flame produced by the ignition of dust at one point 

 was made to ignite a cloud of dust at a point a feet or 

 3 feet distant from the point of inflammation. 



Another experimental paper was contributed by Mr. 

 Pratt, who described some properties of metallic calcium, 

 which seems to have industrial possibilities as a reducing 

 agent. In discussing the paper. Dr. F. M. Perkin 



NO. 1975, VOL.. 76] 



mentioned his own experiments with turnings of metallic 

 calcium, which has a more powerful reducing action om 

 oxides than aluminium. 



The reports of the research committees were as usual 

 of considerable interest. Dr. Lowry, in the report on 

 dynamic isomerism, brought forward very definite evidence 

 in favour of his view that the isomeric change, which 

 usually takes place when nitrocamphor is dissolved in 

 chloroform or benzene, does not occur spontaneously, but 

 is conditioned by the presence of minute traces of alkaline 

 impurities. So sensitive is this change to piperidine that 

 it is complete in ten hours under the influence of so 

 small a quantity as N/ 1,000,000. 



Dr. Orton's report on the transformation of aromatic 

 nitroamines also laid stress on the important part played 

 bv the transforming agent in intramolecular changes- 

 which, accepting Armstrong's view, is regarded as form- 

 ing an additive compound with the nitroamine. Dr. 

 Crossley's report on hydroaromatic substances, besides 

 giving an account of the researches made by the committee, 

 included the usual valuable summary of recent work done 

 in this field. 



The discussion on the chemistry of flour was opened by 

 Mr. A. E. Humphries with a short paper entitled " The 

 Causes of the Quality Strength in Wheaten Flour." TO' 

 make bread of the quality required in this country to- 

 day what are known as strong flours are required, that 

 is, flours which have the capacity of making big, shapely 

 loaves. Most English-grown wheats are deficient in this 

 quality of strength, and give what are known as weak 

 flours. When attempts are made to grow a foreign strong 

 wheat in this country, the yield of grain and straw is, as 

 a rule, too low to make the culture pay. It has been 

 the object of the Home-grown Wheat Committee of the 

 National Association of British and Irish Millers to pro- 

 duce such wheats in England as shall combine strength 

 with maximum crops of grain and straw. In addition 

 to botanical and field work, this problem has demanded' 

 the solution of the question, What is the ultimate cause 

 of strength and the nature and source of those constituents 

 which confer on some varieties of wheat the inherent 

 quality of strength and the power of transmitting it? 



It has been proved that though climate and soil influence 

 quality, they are not the determining factors in the pro- 

 duction of strength, for though the strongest wheats are 

 ordinarily produced in districts where the winters are cold, 

 the summers hot, and the summer rainfall high, certain 

 varieties possess and retain the inherent quality of strength 

 when grown in England. Manuring or early cutting at 

 harvest time has no beneficial effect on quality. Quick 

 growth or rapid maturation is not correlated with strength, 

 nor does the percentage of natural moisture in well- 

 harvested wheat indicate it ; indeed, in certain cases the 

 addition of water to wheat materially increases its effective 

 baking strength. 



The term " strength " has been loosely applied to cover 

 several characteristics. In the view of the committee it 

 should not be measured by the quantity of water required 

 to make doughs of a standard consistency, nor by the 

 quantity of bread produced per sack of flour used, nor by 

 the way a flour behaves in the dough, but by its capacity 

 for making big, shapely, and therefore well-aerated 

 loaves. This definition covers two characteristics ; one, a 

 flour's capacity for making gas in yeast fermentation _; the 

 other, its capacity when made into dough for retaining 

 the gas so generated. 



The gas-making power will depend largely on the per- 

 centage of natural sugar any given wheat contains and 

 its diastatic capacity. These characteristics vary sub- 

 stantially in different' wheats. The baker can, and does, 

 influence the quantity of gas generated in baking. The 

 retention of gas when made involves complex problems. 



Mr. A. D. Hall pointed out that the old idea that the 

 wheat plant takes definite materials out of the soil_ to 

 give it strength is incorrect, and emphasised the view 

 that each type of wheat elaborates a mixture of starch, 

 proteins, &c'., of definite proportions right from the very 

 beginning, so that the plant as an individual affords a 

 characteristic product. Strength on this assumption is a 

 congenital factor, and probably a " character " in the 

 Mendelian sense. 



