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��ill the service, mado a Llctermiued effort to <lefcal it, which was only so far successful as to defeat it in the senate once of the three times it was there considered after leaving the house of repi-esentatives. where it was passed by a small majoritj-. By some it is believed that the whole proceeding originated in repub- lican party warfare against the ' mugwumps ' and free-traders at Yale college. This much is certain, that the ordinary friendliness which might exist between the college and the state was lacking in the case of many members of the general assembly. The governor, who was known to be personally strongly in favor of the observatory service, found himself in a delicate {x>sition, and doubtless^ in the absence of any thing unconstitutional in the repeal, took the only courae open to bim which would be open to no misconstruction.
��We copy Ibis with hearty emphasis and ap- proval, for it points out precisely the difficulty under which our scholars labor. But whik in Great Britain, and in continental Europe generally, the surveys from which good school- maps might be constructed are already well advanced or completed, in our country they are either neglected or only just begun i and it is even still almost always a difQcult matter to persuade state legislators, from whom appro- priations flow, that good maps are needed. It is no exaggcrnlion to say that the educational value of such maps as are now in preparation in New Jersey and Massachusetts is alone more than their cost to the stale ; and we shall watch for the better leaching in the co schools, that must follow their couipletioQ,> with as much interest as for the inoeptiou ofl similar work in other states.
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��Pkukessou Jahf.s Geikie of Edinburgh con- tributes a very valuable article on the physical features of Scotland to a I'ccent number of the new Scottish geographical magazine. It is illustrated by a beautiful little orographical map of Scotland by J. Bartholemew, in which the physical relief is finely brought out. Com- menting on this, and on the excellent maps of the Ordnance survey on which it is based. Professor Geiliie concludes with the following paragraph : —
" Will) iac\> admirable ciirUigra]i1ilcal work before them, how IcMig will iotelllgent teorhera continue to tolerate Ihose antiquated monatrosi lies which so o[|«n do duty as wall-mapa In their schoolrooma ? Surely more advantage ougbt to be taken of the progrsaa made within the last thirty or forty yeara in our knowledge of the phjBlcal features of our iioun- try. It Is time that the youth in all our schools should be able to gather from their maps an accurate notion of the country in which they live; that they should see the form of its surface depicted with an approach to trutb, and learn Bomething more than that so many principal rivers flow in so many differ- ent directions. With a weli-drawa and faithful oro- grapliical map before him, the schoolboy would not only have hia latwrs lightened, but geography would become one uf the most interesting of studies. He would see in his map a recognizable picture of a country, and not, as at present is too often the case, a kind of mysterious hieroglyphic designed by the enemy for his confusion."
��LETTERS TO THE EDITOR.
��In vour issue of Marcli 27, you publish an article H liy Dr. Franz Uo^, upon ' Mr. Metvllle's plan for ' reiichlng the north pole,' in which there are tonie statements that shonld not pass unchallenged. They occur in the discussion uf the effect, upon the sui>- poaed ' Ice-cap,' of centrifugal force due to the earth s
The formula for calculating the effect of centrifu- mb' gal force is a well-known and simple one. C = ^ 5 ,- .
in which d — velocity in feet per second, r= radios in feel, to — weight of the mass acted ou, and C is the centrifugal force in pounds. Apply this to lati- tude 85°, r = 34S miles, or 1,821,4)00 feet, and e = I3S4 feet per second.
Then, if we taki pound, or about from the pole, southward, upon e ice, — a force which Is approximately one foiu-tbcm- sandth of the weight of the body acted upon, insMad
��a cubic foot of ice, C = A of a e hundred grains of phII, away iward, upon each cubic foot of
��e hundred
. single block or in a broad or heaped mass, n difference in the result; tor each onit ol t independently of each other unit. siitrifugal force goes, it could neither nr-' ,r the hypothetical 'ice-cap.'
���In the controversy between Mr. HelvUle and ] Boaa respecting the supposed polar ice-cap, both p lies appear lo take an erroneous view of the »" of ' centrifugal force.'
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