620 



NA TURE 



[October 20, 1904 



Manchester. 

 Literary and Philosophical Society, October 4.— Prof. 

 W. Boyd Dawkins, F.R.S., president, in the chair.— Mr. 

 Charles Bailey exhibited some specimens of Sisymbrium 

 strictissimum, L., which had been sent him by Mr. James 

 E. McDonald, of Stockport, as occurring at Heaton Mersey, 

 where it had been established for the last fifteen years. He 

 remarked that this genus, apart from the aboriginal species, 

 was already represented in Lancashire and Cheshire by two 

 aliens, S. polyceratium at Birkenhead, and S. pannonicum 

 at St. Anne's-on-the-Sea and elsewhere. S. strictissimum 

 is, therefore, a third colonist of this genus which has 

 obtained a permanent footing in our flora. — Prof. W. Boyd 

 Dawkins, F.R.S., directed attention to a new cause of 

 folding of the rock other than that which has been long 

 recognised by geologists as ultimately due to the folding 

 of the outer layers of the earth as they follow the contracting 

 nucleus. The deep cuts made through valleys to make 

 watertight barriers in the construction of reservoirs revealed 

 the fact that the bottom of the valleys, wherever it was 

 formed of shales and thin sandstones, was more or less 

 folded and contorted. These folds and contortions caused 

 the shales to let the water through with more or less 

 freedom, and he had been called in repeatedly to advise as 

 to how far it was necessary to carry the puddle trenches 

 down below the valley bottom. He found, as a matter of 

 experience, that these folds were superficial, and if the sink- 

 ing were made to a sufficient depth below the bottom of 

 the valley they disappeared altogether. It was therefore 

 obvious that they were not due to deep-seated movements 

 of compression resulting from the contraction of the earth. 

 They are due to the relaxation of pressure caused by the 

 removal of the rock by denudation from the area of the 

 valley, and are analogous in every particular to " the creep " 

 in coal workings, caused by the excavation of coal, by which 

 the surrounding strata crush down into the area of relaxed 

 pressure and ultimately fill it up. This may be studied in 

 any coal pit where there is a superincumbent pressure, say, 

 of more than 1000 feet. The two following illustrations of 

 folding and faulting by relaxation of pressure are presented 

 by the puddle trench of the Langsett reservoir belonging to 

 the Shelfield Corporation, and by the two reservoirs now 

 under construction on the head waters of the Derwent by 

 the Derwent Water Board. In the first of these the foldings 

 in question at the bottom of the valley in the shale under 

 the first grit are strongly marked at the surface. These 

 folds gradually disappear, and are based upon a hard black 

 unmoved shale offering a good foundation about 60 feet 

 below the bottom of the valley. This is in the valley of the 

 little Don. The thickness of rocli removed from the bottom 

 of the valley amounted to no less than something like 

 8000 feet of Coal-measures and Millstone Grit. In the case 

 of the Derwent, in which the folding is much more marked 

 and is accompanied by faulting, the thicl<ness of rock re- 

 moved amounted to at least 9700 feet (7200 feet of Coal- 

 measures, 2000 feet of Millstone Grit, and at least 500 feet 

 of Yoredale). In this the movement had not extended 

 beyond a depth of 90 feet. In the case of the Derwent 

 reservoir lower down the river there are two systems of fold- 

 ing and faulting which do not penetrate beyond 60 feet 

 from the surface. At that point a good foundation is found 

 for the puddle trench of the embankment. 



P.XRIS. 



Academy of Sciences, October 10. — M. Mascart in the 

 chair. — The discontinuity of the external work of muscles 

 compared with the discontinuity of their internal work from 

 the point of view of the energy expenditure of the contrac- 

 tion : .A. Chauveau. The results of two sets of experi- 

 ments are given graphically. — On Perrot's experiment : 

 Louis Maillard. A preliminary account of some qualitative 

 results is given. In the first set of experiments twelve 

 succeeded out of twenty-one. In a second set, in which 

 greater precautions were taken to ensure the stability of 

 the receiver, and to avoid currents of air and temperature 

 changes, thirty-one out of thirty-three experiments were 

 successful. — Colour photographs obtained by the interference 

 method without using the mercury mirror ; E. Rothe. A 

 careful examination of some photographs taken bv Lipp- 



NO. 1825, VOL. 70] 



mann's method led to the conclusion that it ought to be 

 possible, by prolonged exposure, to obtain photographs in 

 colour bv the reflection of light on the air-gelatine surface 

 only, and this has been proved experimentally. The method 

 presents the advantages of being applicable in any apparatus 

 without the use of special material. — On the temperatures 

 of transformation of steels : Georges Charpy and Louis 

 Grenel. Three methods were applied to each sample, 

 making use of the electrical resistance, the expansion, and 

 the thermoelectric power. It was found that the thermo- 

 electric and dilatometric methods show no well marked corre- 

 lation except for the softer steels. On the other hand, the 

 results furnished by the electrical resistance and dilatometric 

 methods agree closely qualitatively and even quantitatively 

 within the limits of experimental error. — Substituted deri- 

 vatives of phenyldiazoaminobenzene : L^o Vig^non and M. 

 Simonet. The preparation and properties of several substi- 

 tution derivatives of phenyldiazoaminobenzene are described. 

 These substances are easily prepared by the interaction of 

 the substituted diazoanilines with diphenylamine, and 

 possess the general properties of the diazoamines, being 

 usually unstable. — The influence of castration on the 

 physique : Eugene Pittard. — Culture of a trypanosome of 

 the frog ; A. Billet. — On some Hasmoflagellaj of marine 

 Teleostea : C. Lebailly. — New geological observations on 

 underground sheets of water in the Brenner district : Pierre 

 Termier. 



CONTENTS. PAGE 



Odoriferous Substances Used in Perfumery. By 



Prof. R. Meldola, F.R.S 597 



Systematic Botany jgg 



A Text-Book of Navigation 599 



Our Book Shelf :— 



Owen : " Birds in their Seasons." — R. L 600 



Witchell : " The Cultivation of Man " 600 



" Richard Meyer's Jahrbuch der Chemie for 1903." — 



J. B. C . 600 



Wislicenus : " Astronomischer Jahresbericht." — 



W. J. S. L 600 



Letters to the Editor: — 



The Forest-pig of Central Africa. — Sir H. H. John- 



ston, G.C.M.G., K.C.B 601 



Mendel's Law : a Crucial Experiment. — R. H. Lock 601 

 Rock Pressure at Great Depths. — Geoffrey Martin ; 



Hon. Charles A. Parsons, F.R.S 602 



The Berlin "Thinking" Horse. — Rev. Joseph 



Meehan 602 



Misuse of Words and Phrases. — F. Escombe . . . 603 

 Science in Sport. {Ilhistrated.) By C. G. K. . . 603 

 A German's Description of Italy. (I/his/iah-d.) By 



Prof. G. H. Bryan, F.R.S .... 605 



Disease-Proof Potatoes 606 



Notes. {Illustrated.) 607 



Our Astronomical Column : — 



Encke's Comet 610 



Structure of the Oxygen Bands in the Solar Spectrum 610 



Recurrent Markings on Jupiter 610 



Comparison of the Intensities of Photographic Stellar 



Images 610 



Observations in the Southern Hemisphere ... 610 



The Classification of Stars According to their 

 Temperature and Chemistry. I. {Illustrated.) 



By Prof. A. Fowler 611 



Recent Improvements in the Diffraction Process of 

 Colour-Photography. {Illustrated.) ByProf. R. W. 



Wood 614 



The Agricultural Education Conference at Gloucester 616 

 The Spread of Plague. By Dr. E. H. Hankin . . 6l6 

 Investigations on the Nutrition of Man. By Prof. 



W. O. Atwater 617 



University and Educational Intelligence 618 



Societies and Academies 6ig 



