POPULAR MISCELLANY. 



7 6 3 



strontia alone may occasion some difficulty 

 by reason of the white precipitates of double 

 hyposulphites, which they form with the 

 same reagent ; but it is very rare to meet 

 them along with potassa, and they are very 

 easily detected and removed. 



Prevention of Fires in Coal-Mines. In 



an address on fires in mines, Mr. Richard P. 

 Rothwell affirms tbat the most efficient pre- 

 ventives of such fires, from whatever cause 

 they may come, are to be found in educa- 

 tion, in increased knowledge of the causes 

 of fires, and a better appreciation of the 

 working of these causes. Mine-managers 

 he would compel to undergo strict examina- 

 tions, nor would he allow any one to under- 

 take the responsible duties of this place 

 without a certificate of competency from a 

 qualified board of examiners. He would 

 not, however, stop here, but would have the 

 miners themselves instructed as to the causes 

 and preventives of the dangers they meet 

 with in their work. Special free instruction 

 upon these points might be furnished at 

 every colliery ; and this could doubtless be 

 accomplished by encouraging the giving of 

 popular lectures, by practical miners and 

 engineers, on subjects of interest to the 

 miner, and by giving small prizes to those 

 who pass the best examination on subjects 

 of daily practical application in their call- 

 ing. Greater knowledge always makes bet- 

 ter workers, and mine-owners would find in 

 this a good return for the expense incurred. 



Economy of the Electric Light. In a se- 

 ries of experiments on electric light, Prof. 

 W. A. Anthony used an electro-magnetic 

 machine of the Gramme pattern, driven by 

 a five-horse Brayton petroleum-engine. The 

 engine consumed a little over 6$ pounds of 

 crude petroleum per hour. The lamp u<-d 

 in the engine, by which the explosive mixt- 

 ure is fired, had a one-inch flat wick, and 

 consumed 29.8 grammes (459 grains) of oil 

 per hour. The power resulting from the 

 motion of the engine, when applied to the 

 electric machine, produced a stream of elec- 

 tricity or electric light having an illuminat- 

 ing power equal to that of 234 of the lamps 

 mentioned, showing that three times more 

 light may be produced from a given quan- 

 tity of oil, if its energy is converted first 

 into mechanical power and then into elec- 



tricity, than if the oil is directly burned in 

 a lamp. 



Southern Illinois Academy of Science. 



The Southern Illinois Academy of Science, 

 a newly founded scientific association, with 

 its seat at Carbondale, has for its objects 

 the investigation 1. Of the ethnology and 

 history of Southern Illinois, including its 

 antiquities and aboriginal remains ; 2. The 

 geology, botany, and zoology, of that sec- 

 tion ; and, 3. To encourage the production 

 of original papers on the above, and on 

 special mathematical, astronomical, and me- 

 teorological subjects, as well as on the origin 

 and meaning of the names given to localities 

 by the Indians and the first white settlers 

 of the country. The Academy is engaged 

 in making a collection of materials illustra- 

 tive of the field of research to which it has 

 devoted itself, and has issued a circular 

 calling for contributions of archaeological 

 and aboriginal remains, historical notes, 

 maps, sketches of mounds, natural history 

 specimens, etc. The Secretary of the Acad- 

 emy is Prof. Granville F. Foster, Carbon- 

 dale, Illinois. 



Threatened Eruption of Blount Vesu- 

 vius. For many weeks Mount Vesuvius has 

 been threatening an eruption. Prof. Boyd 

 Dawkins, who visited the volcano in January, 

 found, on arriving at the mouth of the cra- 

 ter, that it was filled with dense vapor like 

 a fog. A low, roaring noise could be heard, 

 and occasionally there was a flash of light, 

 probably the reflected glare of the lava surg- 

 ing about in the volcano. Undismayed by 

 these symptoms of internal disturbance, 

 Prof. Dawkins went down seven or eight 

 feet below the crater's edge, and found that 

 he could light pieces of paper in holes which 

 he dug with his hammer in the black ash on 

 the inside. He is of the opinion that Ve- 

 suvius performs the duty of a safety-valve 

 to a very large portion of the earth. At pres- 

 ent the mountain is in a very restless state, 

 and there may be an outbreak at any mo- 

 ment. The event is looked for with great 

 interest by the inhabitants of Naples, as it 

 will bring sight-seers from all parts of the 

 world to their city. 



The Challenger Collection. The collec- 

 tions of marine animals made by the Chal- 

 lenger Expedition are declared by Prof. 



