February 2, 1899] 



NA TURB 



formed globe would be identical with that on the earth ; for 

 there would be a northern concentration of land, and a southern 

 excess of water ; the geographical shapes — except in the case of 

 the two polar units — would be triangular, and land and water 

 would be antipodal. 



The agreement between the facts of geography and the re- 

 quirements of the telrahedral theory goes further. The main 

 watersheds and mountain systems — which are by r.o means co- 

 incident — have both a telrahedral plan, forming a girdle in the 

 northern hemisphere and three approximately equidistant 

 meridional lines in the southern hemisphere. 



The first obvious objection to the hypothesis of telrahedroid 

 deformation of the lithosphere is that physicists having proved 

 the rigidity of the earth, any such deformation is impossible. 

 But the arguments in favour of the earth's rigidity apply to the 

 globe as a whole, and do not debar limited deformation of the 

 crust. Such elasticity is now regarded as demonstrated by 

 the movements of the pole, under such trivial influences as the 

 unequal melting of the polar ice or unbalanced falls of snow. 

 The second objection is that the earth is known to be an ob- 

 late spheroid, and therefore is not tetrahedrally deformed. But, 

 owing to the equatorial flattening of the world, it is not a 

 spheroid of revolution ; owing to the differences of shape between 

 the northern and southern hemispheres, it is not even an 

 ellipsoid. Herschel pithily sta'ed the facts in his remark that 

 " the earth is earth-shaped " ; and Listing's term " geoid " is now 

 generally adopted for the figure of the earth. The geoid is, 

 however, by no means a regular figure ; the differences between 

 the astronomical and trigonometrical determinalions of positions 

 show that the form is subject to numerous deviations, which 

 cannot at present be attributed to any definite system ; for 

 accurate observations have not been made over a sufficiently 

 large portion of the earth. But there are suggestions that, 

 like the physical features of the earth, the major geodetic vari- 

 ations n.ay be on a telrahedral plan ; for there is evidence of 

 great deficiency of gravity in two areas (East Russia and Central 

 U.S.A.), which may represent two of the three minima which 

 should occur in the northern land belt. The ordinary explan- 

 ation of these deficiencies in gravity — viz. that they are due to 

 vast subterranean blocks of light material — is improbable ; be- 

 cause in the Russian case the existence of such blocks is dis- 

 proved by observations on deviations of the plumb-line (Hel- 

 mert) ; and in the American case, Mildenhall has shown that 

 no reasonable, or even possible, assumption will explain the 

 facts. The agreement of gravity observations with BessePs 

 ellipsoid in Central Europe, and their approximation to Clarke's 

 ellipsoid in Eastern Russia (as shown by Ilelmert), may indi- 

 cate that both ellipsoids accurately represent the curvatures of 

 the two areas on which they were mainly based, and that they 

 merge into one another along the line of the East African 

 meridional edge. 



Geological evidence gives important support to the tetrahedral 

 hypothesis, for the northern land belt appears founded on three 

 great "schild" (Suess) or "coigns" of Archean blocks; these 

 Scandinavian, Canadian, and Manchurian coigns are 120° aj.art. 

 The significance of the angular distance between them was 

 first pointed out by De Lapparent in the case of the first two. 

 South of the coigns lines of elevation on the meridional edges 

 would be expected ; and, though the geological structure of 

 the country along the three lines differs fundamentally, the 

 three lines of recent or still continuing earth-movements of the 

 Andes, Erythrean rift-valley, and East Australian coast occur 

 in the right positions. That tetrahedral geological symmetry 

 is not only an incident of the iiresent, is shown by the distribu- 

 tion of land and water, and by the arrangement of the mountain 

 system at the end of the Pakeozoic ; for both were on a tetra- 

 hedral symmetry. But in that period the present arrangement 

 was reversed, the land belt being southern and the ocean belt 

 northern in position ; the position of the meridional land lines 

 was the same as at present. 



Such a change in the areas of tetrahedral flattening would 

 be impossible in a stationary world ; but in a revolving globe 

 the collapse, due to contraction, is steadily resisted and confined 

 within narrow limits by the effects of the rotation, which 

 tends to restore the world to the more stable spheroidal form. 

 The great mountain building periods of the earth's history may 

 be due to instability resulting from periods of slow deformation ; 

 and the periods of great marine transgressions (e.g. the repeated 

 Mesozoic transgressions after the mountain elevations at the 



NO. 1527, VOL. 59] 



close of the Palceozoic) are easily explained as due to the 

 restoration of more regular spheroidal form. 



Hence the distribution of land and water on the globe may 

 be regarded as the resultant of two opposing forces, collapse 

 due to secular contraction causing deformations, and the tendency 

 due to the earth's rotation towards the recovery of the spher- 

 oidal form. The plan of the earth may be attributed to the 

 continuous foundering of the lithosphere in consequence of the 

 unceasing shrinkage of the centrosphere. 



UNIVERSITY AND EDUCATIONAL 

 INTELLIGENCE. 



Oxi~ORD. — Among the lectures announced for this Term may 

 be noted : — Prof. Burdon-Sanderson on general pathology. Dr. 

 Ritchie on special pathology, Prof. Thomson on cranial nerves 

 and digestive system, Prof. Esson on synthetic geometry of 

 conies and cubics. Prof. Turner on mathematical astronomy. 

 Prof. Miers on physical properties of crystals, Mr. Bowman on 

 microscopical examination of crystals. Prof. Elliott on elliptic 

 functions. Prof. Clifton on electricity, i\Ir. Walker on physical 

 optics, Mr. Goodrich on aves and mamnmlia, Mr. Bourne on 

 Ctenophora, Prof. Odling on the sugars, Mr. Watts on organic 

 chemistry, Mr. Veley on physical chemistry, Mr. Marsh on 

 stereo chemistry, Prof. Gotch on physiology of the excitable 

 tissues, Mr. Burch on physiological physics. Prof. .Sollas on 

 evolution of the earth and on palaeontology, Prof. Tylor on 

 development of culture, Mr. Barclay-Thompson on sauropsidan 

 morphology and pala;ontology. The other lectures announced 

 are more particularly devoted to the general subjects required 

 for the schools. 



Elections will be made in the course of the present term to 

 the Sedleian Professorship of Natural Philosophy, vacant by the 

 death of Prof. Bartholomew Price, and to the Linacre Pro- 

 fessorship of Comparative Anatomy, vacant by the resignation 

 of Prof. Ray Lankester. 



Cambriiige. — The Duke of Devonshire, Chancellor of Cam- 

 bridge University, presided on Tuesday over a meeting at 

 Devonshire House to consider the financial needs of the 

 University and the establishment of a Camljridge University 

 Association. A full report of the meeting appeared in yester- 

 day's Times. The Chairman set forth the various requirements 

 of the University, in buildings and endowments, to meet the 

 increased demands of the day, and said that altogether some- 

 thing like half a million was needed. He announced that he 

 would contribute 10,000/. to the endowment fund. .K contribu- 

 tion of 10,000/. was promised from Lord Rothchild's firm, and 

 the Drapers' Company intimated their intention of contributing 

 800/. a year for ten years in support of a Professorship of -Agri- 

 culture. It was resolved to form a Cainbridge University Asso- 

 ciation for the purpose of enlarging the resources of the Llni- 

 versily. 



The following gifts to educational institutions in the United 

 States are announced in Science : — The late Henry Clark 

 Warren, of Boston, an accomplished Oriental scholar, has left 

 to Harvard University a large sum principally for the Sanscrit 

 department, but including 10,000 dollars for the Peabody 

 Museum of American archaeology and ethnology, and 10,000 

 dollars for the Dental .School. The same University receives 

 5000 dollars by the will of the late Susan B. Lyman, Dedham, 

 Mass., and 10,000 dollars by the will of the late Mrs. Mary Ann 

 P. Weld, of Boston, the latter sum being for the purpose of 

 founding a Christopher Minot Weld Scholarship. The 

 Teachers' College of Columbia University has received an 

 anonjnious gift of 10,000 dollars. 



The Technical Education Board of the London County 

 Council have arranged to award four scholarships of the value 

 of 150/. each, tenable from Easter to Christmas 1S99, in some 

 higher commercial school or schools on the continent. Candi- 

 dates must have had experience in teaching commercial subjects, 

 and must possess a good conversational knowledge of the 

 language of the country in which they proposed to hold these 

 scholarships. The Board's object is to afford to teachers who 

 were well acquainted with some branch or branches of com- 

 mercial education an opportunity of making themselves ac- 

 quainted with the organisation and methods of the more suc- 

 cessful commercial high schools of the continent. Sir Philip 



