September 20, 191 7] 



NATURE 



51 



releases threads from the spinnerets. Mr. Hewitt's 

 observations, though briefly stated, are sure to attract 

 the attention, not only of students of the Arachnida, 

 but also of all who are interested in animal behaviour. 



Mr. G. F. Becker (United States Geological Ssurvey, 

 Professional Paper 98— N) investigates the " Mechanics 

 of the Panama Canal Slides," and concludes that "a 

 limit is set to the vertical height of a cliff or [of?] 

 any rock." This limit allows a face of 3700 ft. in 

 granite, which is well above that of El Capitan in 

 the Yosemite Valley. When breaks have opened 

 parallel to the rock-face, a horizontal shear has started 

 at the base of the cliff, and outward movement can 

 be checked only by the removal of material and the 

 sloping back of the surface of the unstable mass. 



We have received a copy of a publication of the 

 Carnegie Institution of Washington entitled "A His- 

 tory of Transportation in the United States before 

 i860." The large volume, which is the work of many 

 authors, has been put together and edited by Miss C, E. 

 MacGill. The development of transportation is traced 

 from the trails of the earliest settlers, through later 

 roads, turnpikes, and canals, to modern railways. 

 The study is mainly historical and economic, but the 

 geographical point is not lost sight of, particularly in 

 the chapters on the early trails and on the canals and 

 waterways. Coloured maps show the navigable rivers 

 of the United States, the canals, and the railways in 

 operation in 1840, 1850, and i860. There is a biblio- 

 graphy of several hundred entries and a full index. 



The United States Coast and Geodetic Survey cele- 

 brated the centenary of its commencement on April 5 

 and 6, 1916, and the addresses which were then de- 

 livered have been recently published by the Survey. 

 These addresses summaiise the past work of the Coast 

 and Geodetic Survey in the fields of geodesy, verifica- 

 tion of standards, terrestrial magnetism, hydrography, 

 tidal investigations, etc. They give a convenient sum- 

 mary of the work which has been accomplished, and 

 we notice that throughout its history the Survey has 

 always given a prominent place to investigation and 

 research, while the design and improvement of instru- 

 ments for the execution of the highest class of geo- 

 physical operations have been kept in mind, and much 

 ."has been done in this direction. 



When the new Swedish State Museum of Natural 

 History was opened to the public the palaeobotanical 

 •department was not complete, owing to the illness of 

 Prof. Nathorst. The collection, which, besides fossil 

 •plants, contains also the recent Archegoniates, has now 

 •been arranged in its new quarters, which are appro- 

 priately adorned by busts of A. E. Nordenskiold and 

 ^Oswald Heer, as well as by coloured pictures of past 

 floras. The small collections of fossil plants which 

 -belonged to Swedenborg, Per Hasselquist, Hisinger, 

 and others are kept together for the sake of their 

 historical interest. The remaining exhibited fossils 

 are arranged in two series. One, in cases along the 

 walls and by the windows, is systematic, and repre- 

 isents the morphological development. The divisions 

 adopted are : Equisetales, Pseudoborniales (a group 

 hitherto found only in the Upper Devonian rocks of 

 Bear Island), Lycopodiales, Filicales, Pteridospermeae, 

 Cycadophyta, Ginkgogales, Cordaitales, and Conifer- 

 ales. The other half of the collection is arranged 

 stratigraphically, and occupies several cases in the 

 middle of the hall. The main study-series are in other 

 rooms. Thanks to the energy of Prof. Nathorst, all 

 these series are not only remarkably rich, but also of 

 high scientific value from both the geological and the 

 botanical aspect, and it is needless to add that the 

 department is fuUv provided with laboratories and all 

 that is required for the care of so important a collec- 

 tion. 



NO. 2499, VOL. 100] 



In order to release part of the large quantity of grain 

 used in distilleries and to augment the food supplies 

 of the country a reduction of the amount of potable 

 spirits produced has been enforced. One of the conse- 

 quences of this restriction was the curtailment of the 

 output of yeast available for bread-making. To meet 

 this possible difficulty Mr. Julian L. Baker was asked 

 by the Royal Commission on Wheat Supplies as to the 

 possibility of using brewers' yeast for the purpose. The 

 results of his investigations are published in the Journal 

 of the Society of Chemical Industry for July 31. The 

 conclusions drawn are : (i) That a mixture of distillers' 

 yeast and brewers' yeast (from any part of the United 

 Kingdom) will effect a satisfactory fermentation of 

 dough, the brewers' yeast being contributory to the 

 fermentation and not merely a diluent ; (2) that, using a 

 mixture containing 33 or 50 per cent, of brewers' yeast, 

 the doughing period will be slightly prolonged (about 

 20 per cent.) if the yeast rate i<=: low; (3) that brewers' 

 yeast alone is useless in the ordinary " quick doughing " 

 process, but with it good loaves can be made 'of a 

 "slow dough"; (4) that a deficit in the supply of dis- 

 tillers' yeast to bakers could be met by means of 

 brewers' yeast within certain limits; (5) that brewers' 

 yeast alone will produce palatable loaves; and (6) that 

 with the present output of beer 200 to 250 tons of 

 brewers' yeast per week would be available for bakers 

 at a much lower price than that paid for distillery 

 yeast, of which 700 tons are used weekly. In order to 

 avoid the risk of imparting a yeasty and bitter flavour 

 to the bread, the brewers' yeast should be washed with 

 a dilute solution of salt and then submitted to a short, 

 brisk fermentation in a dilute mash-tun wort. Mr. 

 Baker is of the opinion that bakers could use a mixture 

 of equal parts of brewers' and distillers' yeast without 

 any serious inconvenience to their trade or disadvantage 

 to the public. 



That caustic soda solutions at temperatures in the 

 neighbourhood of 100° C. produce brittleness in soft 

 steel has long been known and has been the subject 

 j of several investigations. No satisfactory explanation 

 I has yet been reached, and the matter has been recently 

 : taken up by Prof. S. W. Parr and further investigated. 

 i The account of his work is published in Bulletin 

 1 No. 94 of the Engineering Experiment Station of the 

 ; University of Illinois. That the embrittling effect of 

 j caustic soda is due to the evolution of hydrogen and 

 i its absorption by the steel in the nascent state is 

 j generally conceded. The author shows that during 

 the action of the alkali at ioo°C. the electrical poten- 

 tial of the steel is considerably raised, and that it ex- 

 tends from the surface into the specimen for a distance 

 of, at any rate, 0-30 in. This increase is also 

 i brought about by immersion in dilute acids and by 

 cathodic polarisation. The potential is in all cases 

 higher after treatment of any sort that evolves nascent 

 hydrogen, and this fact points to the occurrence of a 

 molecular change in the steel. This high potential 

 disappears in many cases after a lapse of time, and 

 after heating to from 100° to 200° C. in air, but no 

 I relation was established between its presence and the 

 \ existence of brittleness. Indeed, the author states 

 j that the potential increased long before brittleness was 

 j manifested. By using sodium dichromate as a de- 

 } polariser in the caustic soda solutions the author found 

 I that the rate of corrosion at 280° C. was much dimin- 

 j ished, and that the toughness of the steel, as judged 

 I by the repeated bending test, suffered no deterioration. 

 A complete explanation of the cause of brittleness is 

 I still to seek. 



In Bulletin No. 95 of the Engineering Experiment 

 Station of the University of Illinois Messrs. Yensen 

 and Gatward describe the results of a research on the 

 properties of iron-aluminium alloys. The alloys were 



