Arizona silver belt., 1899-10-19

it. is difficult sometimes to draw the line between species. The principal constituents are sanidine, oligoclase, hornblende. sometimes augite, mag neSian mica. magnetic and some other minerals. Rhyolite is trachte .'n which a distinct tiuidal structure hay be seen with aid of the micro scope, and contains distinct blebs of quartz Liparte is a dense variety of rhyolite.
 So far as known, Prof. Tucker oi Columbia university, recently pro duced the greatest heat known to man. By means of specially con structed electrical furnace and cur rent of unusual power temperature was created of sufficient feNency to vaporate steel. hard quartz, and even platinum. The heat obtained was 6j00 degrees. Boiling water at sea level means a temperature of PIP deg rees Fahrenheit, redhot iron sGo deg rees. Steel meltS at 5000 and boils like water at 3500 degrees.
 On the Pacific coast gold is found n beach sands in several counties of Cal iforna, Oregon and Washington and on the shores of British Columbia and Alaska. In the southern localities many men at various times have worked the sands by devious methods and obtained a small amount of gold
 never enough except in few iSo- lated eases to pay for the expense of fitting up and the labor required. The gold actually exists, and iS found as sociated with layers of black sand, m part magnetic, having been concen- trated by the waves and currents.
 At one time in the history Uf the Grand canyon of the Colorado river in Arizona volcanic eruptions occurred on the plateau in the neighbprhood of the canyon and the black basaltiC lava poured out over the surface and flowed to the edge Of the canyon, over which ii plunged in cascades, tillisg the canyon bottom tO a considerable height. Subsequently the river has cut its way do"n through this hard, tough rock 2nd through the underly- ing rocks indicating that the fresh appearing lava flows, which appear tsh.:a.t. fhey might have been uuppurcd recently are really very old.
 The first important discovery of mines in Utah was made ny soldiers under General CUnuor who cStab- lished the military post at Furi Doug las. east of Salt Lake City in lS63.
 His men were the discuyercrS oi Bing- ham. Stockton. Little Cottonwood and other camps in Utah. and they also found mines at Piochc, Nevada. The most important mining districts of the Wasatch are at those places. where the mountains are highest aud most massive where the granite has upliftcd the quartziteS and limcstpneS and in the latter purphyricS have in- { trudcd the sedimeutary rocks.
 \ water blast fer yenlilatiug a tun- mel in t;UnniSon county, Colo. iS de- ! scrbed as follows; The automatic 1 barrel system of ventilation consists of . barrel sci in the stream outside
 the tunnel the bottom a few inches ' below water level and open: q funnel emptying through q Finch center into ' the top of the barrel. and beside the ! funnel. also inserted into the top of ! the barrel. thc air-pipe leading to the i, tunnel. In this case finch pipe was used By q Hume water iS conveyed ! to the funnel mouth. into which it pourS from a drop of about ] feet, ! This fall gathers a great deal of air and drives q constant even current to I the breast of he tunnel.
 ! Insinking q shaft on q small vein in granite. the vein dipped out of the
 shaft: but, ii being desirable tn con
 tinuc the shaft vertically this was
 done: a> the vein iu it's dip got several i feet from the shaft the granite became extremely hard. X crUSscut was run. showing thc vein to be about , feet ' from the shaft and approximately par
 allcl with il standing vertically. II
 was then determined to enlarge thc
 shaft by cutting ullt tu the vein. The
 result was q saving of 3O percent on
 the cost per foot in sinking during thc
 first week and more than N per cent
 during the succeeding weeks. The
 vein eventually dipped back into ihC
 shaft This shows that il is often les,
 expensive tn remove all of the ground
 tu q good breaking crcvicc as q gollgc
 vein ar iisSurc. as il facilitates break
 ing the ground.
 The determination of "orc in place
 bS the measurement of its cubic con
 tents should be made with care: l.
 cubic feet to the ton only applies tt
 solid quartz rock which may contain
 q nominal percentage of Sulphidc o othpr heavy mineral In lead liu,