SCIENCE SIFTINGS.

Hawera & Normanby Star, Volume LIII, Issue LIII, 17 August 1908, Page 2

SCIENCE SIFTINGS.

THE ORIGIN OF MAMMALS.

, All those hairy, warm-blooded quad- j rupeds which suckle their young, and , are hence called mamnaals, are the de- ' scendants of small five-toed ancestors about the size of a spaniel. This is equally true of the elephant, the gor j ilia, the horse, and the ox. In the , sands and clays deposited since the I time of the chalk-sea, the remains j (bones and teeth) of the ancestors of, living mammals -are found in great abundance. These sands and clays, | writes Prof. Ray Lankester, are called ' "the Tertiaries," and are divided in- j to lower, middle, arid upper— whilst we recognise as "Post-Tertiaries" (or Quarternary) the later formed gravel and caves deposits in which the re- j mains and weapons :>f the cave-men i have been found. The Tertiaries consist 6f a series of deposits amounting to about 3000 ft in thickness, and they have taken several million years in depositing — no one can say how many. WHAT MAKES HAILSTONES. The formation of hail through electrical action, according to the hew theory of scientists attached to trie Weather , Bureau at Washington, is an interesti ing and even wonderful process. The I wind draws out a cloud into a long, ' narrow strip. In that form, owing to * the great amount of surface, the cloud evaporates rapidly, and the rapid evaporation produces intense cold. Dry particles of snow are then formed, and these, by friction with the water drops, quickly become charged with negative electricity." But the water drops themselves carry positive electricity, and j since negative attracts positive, a film J of water is formed upon each snow pari tide, and is instantly frozen into a : layer of ice. I At this thickness its outer surface re1 mains moist, the water not freezing there so rapidly, whereupon the electrical charge changes from negative to positive, and the partide is repelled by the water drops and driven to the outer parts of the cloud. Here the increased cold covers .it .with snoir asiam, and the . friction charger, it anew with negative ( electricity. Repulsion is now once' riWro ! , changed -for attracti«n, and 'the' parti- ' r cles rush ' back. into.< the , cloud, gfeceiv- j ihg'\tpon tWr surface auotb'orjfilm,- s£.' f water, which is turned ' into second' ic,e f layers'*/ T m'-':"-' 1 < j ' v.-.- .. ',. j) ;' Thus tbe''g:t?owi/i£tfla;'.sjsone darts,^igr r ; f piling, up its | ■ a'lt[ernajb& layers of ■< snow and ice 4 until ; , gravitation -layers control, . and -«, ,se)tds ' ' itfti^tib.i ,a, jingling .crqwd of its, fel-Jftw^,-f{spin^i^^to the .^roun^.— Science. Joltings. sv»l";rV.' '/• ,^' L %]]". n: >„ .^thde mO^-% >9$ c Gotb. ■•iijCheje^rliest' mention of gol^jif, in w£,' second chapter of •Genesis,.', where li^j ..^elejfijgdjjo^as one of • the metals 'of tne ;f .laTn'dibfj-Sa^illS'WvOT, a P^^s ' alzsolß . ! as early (says Harper's Weekly).' 'T^e with*" ]ihat ; of Egypt, 1 ruleil 'the^Bibilcal world^ j appears to "Kave ' had a silver-currency. "Shekels of silver," and-."piejces of $iljyer" are ( do'nstantly spoken j df. 'Gdld 1 was used chiefly for ornamei^ 1 its m'kl- ; leability and ,ductility . making it tb'e .of metals to handle! ' v ;;jEhe mines which supplied the coinage ; s'of . ■£Ke,^a,nci§nt"wo)cl|&(,, i were^in ;Indial.* ;§olomo!d ? s sailors .- brought, .gold 'from' Ophirv^an ,-unkAown '^bi^a//' by nWy thbtigHt '^be^Miiihon|jiaid, in Sou^h.Central; ju r'ica, {w^ete/tne ruins of pre^-. historical":§ie^nitii|^rts .and mine shafts' have been found; * , jThe' 'Spanish- conquest of South America -flooded the' world , with gold and silver. Prices" rose tenfold during „ a century.' "Before the discovery qf-^'iLmH; erica a faT sheep could , be bought foi* a quarter. \ 0£), and^ '' working ■ men had lived ;sumptuoualy upon o^/cents a' 'day. The se.con"d great influx' of gold occurred during the 50's ..of, the last centuiy, i when; the mi^es bf ; .California and Australia - were discovered, and since then • , there has been a slow rise in the price ! j of commodities, due to the increase of ' the precious metal ; but on the whole ■ the rapid increase in population has .kept pace with the increase of gold!