394 



SCIENCE. 



[N. S. Vol. III. No. 63. 



Loug ago Newberry, and afterwards 

 Stevenson, regarded the coal as metamor- 

 phosed by heat from a gi-eat dike of ernptive 

 rock following the northerly side of the 

 Placer (now Ortiz) mountain. This, which 

 then was but a suggestion, is sufficiently 

 clear as an explanation now. As the center 

 of eruption was in the Ortiz mountains the 

 metamorphism should be most notable near 

 those mountains. That is distinctly the 

 condition, for, at the most southerly point 

 showing the Wliite Ash bed well, the anthra- 

 cite is very hard ; but the change is less 

 toward the north until normal coal is 

 reached in the White Ash mine below 

 Madrid. The gradation is equallj"^ clear in 

 the Cook- Wliite bed ; but the small bed be- 

 tween the main seams appears to contradict 

 the hypothesis, as it is decidedly bituminous 

 at half a mile above the pit, where the 

 White Ash bed yields the hardest anthracite 

 observed. This condition is easily ex- 

 plained by the fact that the small bed is 

 not continuous, being bi'oken by clay seams 

 several feet wide, which sometimes cut out 

 all of the coal ; these seams would prevent 

 the passage of heat from one portion to 

 another. 



The conditions at several localities show 

 that mere proximity to the mass of eruptive 

 rock was insufficient to produce change. 

 The lower plate of trachyte is but 10 feet 

 below the Waldo coal bed in the bore-hole 

 west from Coal cafion, but, though 200 feet 

 thick, it had no appreciable effect upon the 

 coal. The interval between the White Ash 

 bed and the upper plate of trachyte shows 

 insignificant variations along Coal cailon, 

 and it must be approximately the same in 

 the newer parts of the White Ash mine ; 

 yet in the Lucas mine and at all localities 

 south from it the coal is anthracitic ; 

 whereas at all points north from it to the 

 border of eruptive rock one finds only 

 transition coal. It seems clear that direct 

 contact is necessary to produce change. 



Prof. J. F. Kemp describes the eruptive 

 rock as a trachyte closely allied to andesyte. 

 Its outflow then was early, possibly at the 

 time of the Laramide elevation, when great 

 outpourings of andesyte occurred in Colo- 

 rado, Utah, Wyoming and Montana. The 

 coal was completely formed prior to this 

 elevation, prior to any disturbance, there 

 being not only no evidence of pulpiness, but 

 every evidence that the coal was thoroughly 

 hard. It was crushed into minute frag- 

 ments, slick en- sided, like the Utica shales of 

 Franklin county, Pa., or laminated and 

 rolled into leaves, like the Vesisertine coals 

 of southwestern Virginia. The process of 

 conversation was complete before disturb- 

 ance not merely in the lowest beds, but also 

 in the White Ash bed, at nearly 900 feet above 

 the bottom of the Laramie. 



John J. Stevenson. 



THE BONTGEN PHENOMENA. 

 A FEW EARLY RESULTS OBTAINED AT THE UNI- 

 VERSITY OF PENNSYLVANIA. 



The first attempt here to repeat Eontgen's 

 experiments was made on Wednesday, Jan- 

 uary 22d, but without success, owing to the 

 impression obtained from early accounts 

 of experiments abroad that two induction 

 coils were necessary. As a matter of fact, 

 one coil giving a four-inch spark through 

 air is quite powerful enough to produce 

 most of the results that have j'^et been ob- 

 tained. The average current through the 

 primary is about three amperes with an 

 E. M. F. of twelve volts. Our tube is a 

 beautiful lai-ge pear-shaped one, admirably 

 adapted for the purpose. It is about 27 cm. 

 long, and 11 cm. in diameter at the largest 

 end. 



Fig. 1 shows the result of a test to dem- 

 onstrate the possible reflection or refraction 

 of the X-rays when incident upon two very 

 large and white diamonds set in a ring. 

 The gems were placed within a purse with 

 some coins. Certain features of the cutting 



