VOLCANIC PRODUCTS. 347 



porting and selling copies of the American paper, prosecuted him. 

 He argued that it was impossible for him to know, when ordering 

 books from America, that they contained English extracts, and that 

 he ought not to be punished for simply importing and selling books 

 in the ordinary way of business. But the decision was, that an im- 

 porter is bound to ascertain ; or, if he imports without inquiry, he 

 takes the risk that there may be something in the books which he will 

 not be allowed to sell. A more lenient view of a somewhat similar 

 question was taken in an American decision ; it held that a partner or 

 employer is not chargeable with a statute penalty for acts in violation 

 of copyright done without his authority or knowledge by his partner 

 or agent. Some intention to violate the law must be shown, accord- 

 ing to this case, to sustain a prosecution. 



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VOLCANIC PRODUCTS.* 



THE most abundant of the substances ejected from volcanoes is 

 steam, or the vapor of water, which issues in prodigious quanti- 

 ties during every eruption. With it frequently appear numerous other 

 volatile matters the acid gases, hydrochloric, sulphurous, carbonic, 

 and boracic acids ; sulphuretted hydrogen, hydrogen, nitrogen, ammo- 

 nia ; the volatile metals, arsenic, antimony ; and some other substances 

 not usually volatile, but which are nevertheless easily carried away in 

 fine particles when a current of steam is passed over them. These va- 

 rious substances react upon each other, and give rise to the formation 

 of many new compounds. Deposits of sulphur result from the action 

 of sulphuretted hydrogen and sulphuric acid on each other ; hydro- 

 chloric acid forms, with the iron in the rocks, the yellow ferric-chloride 

 which coats the vents, and is often mistaken for sulphur. The iron, 

 lime, and alkaline materials of the rocks are converted by the acids into 

 soluble salts, which, being washed away by the rains, leave a white 

 powdery deposit of silica that so much resembles chalk that travelers 

 have been led to describe islands in which it appears very abundantly 

 as being composed entirely of that substance. Some of the gases, as 

 hydrogen and sulphuretted hydrogen, are inflammable, and may some- 

 times be seen at night playing over the fissures in faint, lambent 

 flames, occasionally brightly colored with metallic salts. These tran- 

 sient flames are not, however, to be confounded with the red, glowing 

 light which is commonly called "volcanic flames," but which is not 

 really a flame, only the reflection in the vapors of the glowing mass in 



* Volcanoes, what they Are, and what they Teach. By John W. Judd, F. R. S. With 

 Ninety-six Illustrations. "International Scientific Series." New York : D. Appleton & 

 Co., 1881. 



