956 



NATURE 



\)i. 



-;y, .c,^3 



aries are m ' * • ' artificial: with one or 

 two except i ■ geonr.ij.liK a! iiu-aninfi. 



The early ^un im lU-. .liwuiui tht- island contitu-nt 

 were senaratinl by long stretches of jnh<jspital>lc coast 

 and still more difticult interior. From these various 

 centres the human settlement developed on old-world 

 lini.« Tlii-; is I'xpressed in thr various state railway 

 , i.iinii-ii uiilio'i' ■•( those of 



1 ill- geographii 'il .md (■(oikhuu naiix ol tlic islrtiid 

 u.ts ()verlooke<l until a mm h l.itcr d.itc. l)ul tin- 

 Coiniiioiiufalth f.-clin>^ ih y\\\\ i n'.,'. I'l.ii.m- rapid 

 hc.'idw .1', :\\\>\ IS rctlfctcl 111 li,' !!' ' nowly 



! lu'Sf 111! ' '» 



scparat* 

 AH iii.ii-'i \ii ti.iii.iii railsvay sch< 

 coiniiioiiu' altli i>njp()sitions in th.< 

 interests of luorf than one state. s - > ^ i- ir ^s.>- 

 shown to indicate tin- (•coiioinic air.i ,. iiidrpciKl.-iU of 

 pnlitirnl divisions, \slii<li ni.iy be regartled as ilie 

 lanterl.iiids ol dittereiil stretches of sea coa-.t. ( >n 

 tins niai> it is ]h,,,iM,- to forecast, with tolerable 

 certaintN, tlie itlincs of the completed 



Australian railw in. Brieflv, this entails an 



outer rin;.^ ot \shu h the elements alrea(l\- e.xist : an 

 inner cni !•■ ; tr,iL;nients of a radial system entting 

 across boih ( ireles and joining' hinterlands with their 

 appropriate imits ; eertain overland lines from north 

 to south and lasi t<i \vi >t. Ihese systems when fully 

 built will nnit\ tin- eontinent and overrule the 

 irlitieialit V ot the ori.^mal states. 



Structure of Greenland. 



WK have recently received, though the work is 

 * * dated 1920, volume 53 of the " Neue Denk- 

 schriften der Schweizerischen Naturforschenden 

 Gesellschaft," ^ containing an account of the Swiss 

 trans-Greenland Expedition of 191 2-1 3. Between 

 southern Greenland at about lat. 64°, where the country 

 was crossed by Nansen in 1888, and Peary's routes of 

 1892-95 through 80° N., the interior of Greenland 

 remained unknown for an interval of more than 1000 

 miles. In order to determine the structure along 

 one line through this gap a Swiss expedition under 

 Prof, de Quervain in 1912 traversed Greenland from 

 the western coast in lat. 69° 46' opposite Disko to 

 the eastern coast in lat. 66°. The journey on the 

 inland ice was begun on June 20. The summit of 

 the ice-cap was crossed on July 8, and its eastern 

 margin was reached on July 21. The party, with 

 dog-drawm sledges, averaged 22 kilometres a day. 

 Meanwhile the western party under Prof. Mercanton 

 investigated the open country on the western edge of 

 the ice-cap to the east of Disko Island. 



The new traverse of Greenland confirms the general 

 accuracy of Nansen's profile, though, as he crossed 

 the country where the ice-cap is narrower but rises 

 to a greater height, his gradients were steeper than 

 those found by the Swiss party. Doubt is tlirown as 

 to the distance inland reached by von Nordenskjold 

 in 1883. The expedition, however, supports his view 

 that cryoconite consists in part of meteoritic material. 

 Nordenskjold's conclusion has generally been rejected 

 and the material explained as dust blown on to the 

 ice from the nearest rocks. Part of the cryoconite 

 collected by the Swiss expedition is regarded as 

 derived from local diorite, but it contains spherules 

 of magnetite which Prof. Mercanton regards as 

 possibly of extra-terrestrial origin. In this view he 

 supports the conclusions of Wulfing and of Swinne 



> " Neue Denkschriften der Schweizerischen Naturforschenden Gesell- 

 schatt " (Nouvcaux M^moires de la Soci6t6 Helv^tique des Sciences 

 Naturelles) Band 53. Pp. xxf4oa+54. (Basel, Genf und Lyon: Georg 

 und Ca, igaa) 



NO. 2826, VOL. I 12] 



(1919). In the absence, however, of proved nickel, 

 the meteoritic origin of the magnetite may still Ik- 

 regarded as open to doubt. 



The western party made careful measurements of 

 the ice movements, and found it to vary from i.-,, 

 than a centimetre a day on the ice front to aj i 

 It is sliown that the bare land in we!5t -central ' 

 l! coveretl 



M 'i)orts the 



of some <jf tilt: high southern niouutaiiis, tlic whole <jf 

 Cireenlaiid w;is once burietl under an ice-cap. Wm 

 account and photographs show the powerful <\ 

 tive effect of frost on bare nx;k.s in the neighbor 

 of ice. The larger part of the volume is occupied by 

 the meteorological observations and results, including 

 ttie r' ' ' ome pilot-balloon > 



i h ptcr describes the lo 



skllll>, ■mil iir, author, I*" '' i\, Hje> l> tin- viuw 



that the Eskimo reach dand from Europe ' 



across the Faroes and .,> ..... 1 ; he regards tne 

 Mskimo as the most primitive .section of the Mon- 

 golian race Tli(> \nliimc is well ill 11st r.i fi»<i by fOUT 



plates of ri; 1 numerous 



figures in t : 



Building Materials made of Waste 

 Materials.' 



By Prof. A. V. L.\rKii;. 



"\X7E have in Great Britain large accumulat: 

 *^ blast furnace slag, of cinders, and clinkt; . ....>i 

 in the neighbourhood of Edinburgh of burnt shale, 

 the residue from the stills of the oil industry. There 

 are three \\a\s in which these materials can be 

 utilised — for the production of bricks, for the pro- 

 duction of cement, and as aggregate mixed with 

 Portland cement or plaster of Paris. The general 

 method adopted for the production of bricks is known 

 as the sand lime process. Briefly, this process con- 

 sists of mixing the aggregate with a certain proportion 

 of lime and water, squeezing it into a brick under a 

 pressure of some two hundred tons to the area of the 

 brick and then steaming under high pressure or in 

 open steaming chambers. Bricks are now being 

 manufactured by this process from sand, blast furnace 

 slag, granulated by being run while hot into water, 

 clinker, town refuse, slate dust, and burnt shale. 



Cement is being manufactured by two of the Scottish 

 steel companies from blast furnace slag granulated, 

 mixed with lime, and then raised to a high tempera- 

 ture so as to form a clinker in the same \s'ay . 

 ordinary Portland cement was manufactured. Tin 

 cement, known in Germany as iron cement, can be 

 sold m this condition, or can be finally ground with 

 a mixture of a certain proportion of raw blast furnace 

 slag. 



The uses of these materials as an aggregate opjens 

 the question of how far it is possible to reduce the 

 content of Portland cement and, at the same time, 

 get sufficient strength for building purposes. The 

 objection to the usual building slab made of cement 

 is that, in order to be able to remove it from the 

 machine as soon as made, the content of water has 

 to be kept low and, consequently, the crushing 

 strength of the finished slab is also low. Two in- 

 teresting methods of getting over this difficulty are 

 the Crozite method, in which the cement bricks were 

 sliced off from the bottom of a column of cement and 

 aggregate, and the method used by the Triangular 

 Construction Compan\", in which a heavy compression 

 is put upon the bottom and top of the slab at the 



' Substance of a lecture delivered at the Royal Academy of .■Vrts, 

 London, on Wednesday, November 21. 



