io6 



THE POPULAR SCIENCE MONTHLY. 



yards from the shaft, and the amount 

 of leading and connecting wire used to 

 bring all the charges into relation with 

 the batteries was 220,000 feet. The 

 charges in the different holes of the 

 same pier were connected so as to ex- 

 plode simultaneously, but a fuse com- 

 posed of a quick explosive was used 

 to connect the system of charges in 

 each pier with those of the neighbor- 

 ing piers. In this way the electric 

 spark, taking effect in a few centres, 

 the ignition was propagated through 

 the whole system, as the explosion of 

 the connecting fuse would advance 

 more rapidly than the destruction of 

 the rock. The several thousand charges 

 in the mine were connected in 23 

 groups, each with 160 fuses, and these 

 were acted upon simultaneously by 23 

 groups of batteries. These were ingen- 

 iously connected in a mechanical ar- 

 rangement so simple and perfect that 

 a child could operate it, and the whole 

 stupendous force that slumbered in the 

 charges was actually released by the 

 touch of a little daughter of General 

 Newton, two years and a half old. The 

 explosion was accompanied by no very 

 stunning effects to eye or ear, and the 

 demonstration was so moderate as to 

 produce great disappointment in the 

 multitudes who assembled to witness 

 it. There was a succession of shocks, 

 lasting a few seconds, with no great 

 noise, a mass of water and debris of the 

 coffer-dam thrown into the air, and 

 the great reef was shattered and de- 

 molished. Long experience in blast- 

 ing, and the close adaptation of explo- 

 sive material to the work done, had 

 enabled General Newton to graduate 

 the amount of power to be developed 

 to the total result ; and so accurate was 

 this adjustment that the explosives 

 spent themselves in breaking up the 

 reef, and no power was left to topple 

 down the houses in the vicinity. Ex- 

 aminations thus far show that the great 

 blast was most effectual, although con- 

 siderable time and much labor will 



probably be required to clear away the 

 broken masses of rock, and gain the full 

 benefits aimed at by the enterprise. 



DR. DRAPER'S BOOK AT ROME. 



TnAT extensive division of the Chris- 

 tian Church which has its headquarters 

 at Rome has claimed and exercised for 

 more than 300 years the right of de- 

 ciding w r hat books its members shall 

 be allowed to read. This power resides 

 in a body of cardinals, designated by 

 the Pope, who issue an "Index" of 

 books containing a twofold catalogue, 

 one of which is of works absolutely 

 prohibited,, and the other of works that 

 are prohibited only until they are ex- 

 purgated, or so corrected by their au- 

 thors as to be acceptable to the Church 

 authorities. The first papal "Index" 

 was published in 1549, by Pope Paul 

 IV. It was made a part of the work 

 of the Inquisition, and this body had 

 charge of it until 158G, when a special 

 commission " The Congregation of the 

 Index" was created, and has been 

 maintained to the present time. Among 

 the early works prohibited by this con- 

 clave were those of Galileo, Coperni- 

 cus, and Kepler ; and, among those for- 

 bidden in more modern times, were 

 Locke's " Essay on the Human Under- 

 standing," and Mill's " Political Econ- 

 omy." Dr. Draper's " History of the 

 Conflict between Religion and Sci- 

 ence" has now the honor of being 

 added to the list of celebrated books 

 which Catholics cannot read without re- 

 belling against ecclesiastical authority. 



This institution of the Catholic 

 Church is itself the most conspicuous 

 example we have of that great " con- 

 flict " which Dr. Draper has so vividly 

 delineated in his little volume. Its rise 

 was coincident with the general awak- 

 ening of thought in modern Europe, 

 which was manifested on the one hand 

 in the Protestant Reformation, and, on 

 the other, in that independent study of 

 Nature by which the sciences have been 



