January 6, 192 i] 



NATURE 



617 



Calendar of Scientific Pioneers. 

 January 7, 1786. Jean Etienne Guettard died. — The 



liscovi-rtr in 1752 of the exlinct volcanoes of Auvergne 



aid the compiler with Lavoisier of a mineralogical 



nap of France, Guettard has been called "the father 



i all the national Geoloj^ical Surveys." 



January 7, 1893. Joseph Stefan died.— Professor 



f physics at Vienna and director of the Physical 



Institute, the law of cooling which bears Stefan's 



name was enunciated by him in iX7<). 



January 8, 1642. Galileo Galilei died.— The founder 

 of the science of dynamics and one of the greatest of 

 the early experimentalists, Galileo, wrote J. D. Forbes, 

 "was beyond all comparison the glory of his age." 

 Some years older than Kepler, Galileo was born in 

 157: at Pisa, where he studied and lectured and 

 made his experiments on falling bodies. The leaning 

 Tower of Pisa now bears the inscription : 



G.ALILEUS G.ALILEJUS 



Experimentis E Summa Hac Turri Super Gravium 



Corporum 



Lapsu Institulis 



Legibus Mot is Detectis 



Mechanicen Condidit 



Ingentibusque Suis Posteriorumque Sophorum Inventis 



Praelusit 

 The astronomical discoveries of Galileo were made 

 while he held the chair of mathematics at Padua. In 

 1609 he heard of the invention of a crude telescope. 

 Seizing upon the idea, he made an instrument to 

 magnify thirty times, and within eighteen months he 

 had observed the mountains and craters of the moon, 

 seen the planets as discs, counted forty stars in the 

 Pleiades, discovered four of the satellites of Jupiter, 

 was perplexed by the curious appearance of Saturn 

 ilue to the ring-system, observed the gibbous, as well 

 .IS the crescent, ph.ase of Venus, and had closely fol- 

 lowed the spots in the sun. He was then at the 

 /i-nith of his career. The greater part of his later 

 ife was passed at Florence, and to this period 

 •long the controversies and persecutions which em- 

 billf-reil his last davs. 



January 9, 1M8. Caroline Lucretia Herschel died. 

 Returning to F-^ngland with her brother William in 

 1772, Caroline Herschel for fifty vears was his most 

 patient, skilful, and zealous assfstant. The minor 

 planet l.ucretia was named after her bv Palisa in iSSq. 

 January 10, 1778. Linnaus died.— Carl von \J\nv\t 

 or I.iiin;i-u>i was born on M.iv ), 1707, at Roeshult, 

 Sweilen. A student at l,un<l and a lecturer at Upsala. 

 through much poverty he clung to his first love of 

 botanv. .\n expe<lition to Lapland was followed bv 

 travels in Holland, England, and France. In 1741 

 he bernirK- professor of anatomy and physics in the 

 Univrrsitv of I'psain, but the following year was 

 anriointied lo the chair of bolanv. His last edition 

 ' his " Svstrma N'alura-" appeare<I in I7(>S. 



January 10, 1833. Adrien Marie Lecendre died. 



'ic ciintemoorarv of I.aolace and Lagrance, an<l the 

 istrurtor of Cauchy and .\rago, Lei/endre was on 

 le Commission for conneclinf Greenwich and Paris 

 friangiilalion. .ind ma<le notable additions lo 

 iriou-. br.-inihe* of hiL't'i r i)i;ilh<tii.it!( •;. 



January 13, 1668. Pierre de Permat died. Horn In 

 'i<- province of Gascony, Format was trained as .1 

 iwyer, and became a councillor of the local Parlia- 

 ■ nf nt Toulouse. He wa« the corresrK)nclent of 

 '•■varies, Torricelli. Pasc.il, Huvgens, \Vallis. nml 

 hers, and made additions to geometrv, the ralculu.s 

 ' probabilities, and the iheorv of numbers. 



I- I ^ 

 NO. 2671 . 106] 



Societies and Academies. 



LOMX)N. 



Faraday Society, December 13.- — Sir Robert Hadfield, 

 Bart., presidtnt, in the chair.— Prof. E. D. Campbell: 

 A force field dissociation theory of solution applied 

 to some properties of steel. Understanding of the 

 properties of alloys has been obscured by the use of 

 the term " solid solution " and by expressing constitu- 

 tion in terms of percentage weights. There is no 

 essential difference between a liquid and a solid solu- 

 tion, and the constitution of both should be expressed 

 as molecular or atomic concentrations per unit 

 volume. The electrolytic dissociation theory in its 

 usual form is inapplicable to alloys. The force field 

 theory is a modified form of it applicable to liquid 

 1 and solid solutions alike. The assumption is made 

 I that in a molecule the electromagnetic force field asso- 

 ciated with the constituent atoms is closed in the 

 combination, but in solution this force field is opened 

 out by the solvent to an extent depending on con- 

 centration and composition. The reactivity of ions is 

 due to the open force fields, and not to the presence 

 of electric charges. In the presence of an impressed 

 e.m.f. the resultant of the reactivity is electrical resist- 

 ance in the case of metallic solutions, and electrical 

 conductance in aqueous solutions. — S. L. Norbury : 

 The electrical resistivity of dilute metallic solutions. It 

 is well known that the small quantities of impurities 

 in solid solution cause a large irKreasc in the elec- 

 trical resistivity of a pure metal. Data are collected 

 showing the relative atomic effects of such impuri- 

 ties, and a certain relationship appears to be brought 

 out by doing so. The author summarises his con- 

 clusions as follows :— (i) .^ comparison with the 

 atomic volumes, intrinsic pressures, electrical resis- 

 tivities, thermo-electric properties, and decomposition 

 potentials of the elements concerned shows that none 

 of these atomic properties can be directly applied to 

 explain the results. It is suggested that the atomic 

 effects are small when there is little electrical attrac- 

 tion between the atoms of solute and solvent, and 

 large according as the electrical attraction between 

 the two is greater. (2) It seems probable that in the 

 dilute solutions quoted the atoms of solute arc not 

 associ.itcd. (3) .Xssuming, for example, the face- 

 centred cube lattice in a dilute solid solution, an atom 

 of solute will be surrounded by twelve equidistant 

 atoms of solvent, and will not be attached lo any one 

 of these atoms in particular. It will, therefore, exert 

 attractive forces on the electrons of the surrounding 

 atoms. (4) It is generallv assumed that metals con- 

 duct the electric current by means of their " free " 

 electrons ; the presence, therefore, of forces restrain- 

 ing the "free" electrons in solid solutions will account 

 for their diminished conductivity. 



Geoloftlcal Society, December is.-Mr. R. I). 

 Oldham, prisident, in the chair.— Dr. T. O. Boiworth : 

 Structure an<l stratigraphv of the Terti;iry deposits 

 in north-western Peru. The westernmost ranges of 

 the .Andes in the north of Peru are of pre-Tertinry 

 age. The Tertiary rocks occupy a n;irrow strip of 

 country between the mountains arul the sea, and ihev 

 consist of 15,000 ft. to 25,000 ft. of clay-shales and 

 sandstones, with thin seams of beach-pebbles and 

 shells. During the Tertiary period a large subsidence 

 u.i- in progress. The stratigrnphical succession is: 



ri. 

 Miocene. Zorrito* Fonnatinn 5000+ 



(Lobitos Formation 5ooo-t- 

 J Claviliihes .Senes I -..„.,-. 

 i Turritella Series I ^ooo-l- 



