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slrikiiig that I may be pardoned for reproducing it liere entire. Ij diffus 

 contained in the Proceedings of the Boston Society of Xatural llistdiepeop 

 and is as follows : — Again 



'■ Dr. Knoeland exhibited several specii.iens of glass, marble and hre or si 

 stones, engraved, carved and grooAed by the aciioii of sand driven laferenct 

 blast of air or steam. The surface being co\ered by perforated paa^ Avei 

 or a stejicil plate, the parts exposed by the perfcjrations are cut rapiig-t)ein< 

 and accurately, \\'hile the covered parts are untouclied, protected, itjlice art 

 supposed by the elasticity of the paper or thin metal. ley we] 



Me drew attention to this industrial process as illustrating the lefteures 

 vantage of difl'iising, as a common branch of knowledge, informatioirork of i 

 the forces of nature, and, in tliis instance, on dynamical geology. fsMe a ] 

 process, Aviiich pron)ises to revolutionize one of the most extensivopdlatio 

 the industrial arts, is siniply carrying out what natural forces luce ? A 

 betm doing to the surface rocks of our continent for ages. limals, : 



Sands carried by strong and steady winds, passing over rocks, ole most 

 w ear them smooth or cover them with grooves and scratches, as notisrfiilly s 

 and figured by ^Ir, Hlake i.u the granite rcx-ka at San Bernardino Pxternal 

 Cal. ; sfe Pacific K. 11. lleporls, vol. ;"», pp. 92 and 231. Quartz r;her of; 

 were there found polished, the softer feldspar being cut away ; ^^•'lnJJBelne] 

 the latter bad been protected by garnets, projections were left, tipiejrnot 

 l)y the hard garnets, poinling like lingers in the direction of the w'ourmc 

 On the surface of the great Colorado desert the pebbles are fire they 

 polished by the drifting sand or variously grooved according ti/isdoin, 

 hardness of their substance. Prof. .1. VVyman also mentions that ^ity tha 

 windows on Ca])e Cod have sometimes holes worn in them bvllycxp 

 drifting sands blown by the winds. me, ai 



[t is the tendency of modern education to pay less attention to?ht unj 

 dead languages aiul to ancient history, as a means of cidture, and i;)t fear 

 to the practical and living issues of the day, and especially to com' either 

 a knowledge of natural phenomena with the elementary instructi >ints of 

 < he school-room. In this particular instance, it is altogether pre! St ass ii 

 that, if the grooving of rocks by the wind-driven sands, long knowid botl 

 geologists and physicists, aiul by them turned to no practical acciCts tho 

 liad been equally weU known to our intelligent and skilful media: And i 

 the process here illustrated would have been invented years ago,io\«ded 

 l)y this time have attained a high degree of perfection. The sanu>reelf, 

 son will apply to other departmt^nts of natural and physical scie attc, 

 and goes to show the wisdom of (hose educators who are endeav^id act 



fit 



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