February 5, 1886.] 



SCIENCE. 



in 



following averages : one pound of anthracite 

 burned under a good boiler yields, in the incan- 

 descent system of lighting, about 40 candles ; the 

 same weight of coal gives from the naked arc- 

 light about 158 candles ; ordinarily arc-lights are 

 shaded so as to lose about one-half their intensity, 

 so that only 80 candles per pound of coal are 

 available ; one pound of bituminous coal will yield 

 from five to six cubic feet of illuminating-gas ; 

 this gas will, in the standard argand burner, 

 yield from 14 to 17 candles. Illuminating-gas is 

 burned at once in the simplest manner, and the 

 amount of machinery and care required by electric 

 lighting offsets its greater economy of fuel, light 

 for light. There is little room for improvement 

 in dynamos, but the most important economies 

 will arise from more skilful use and design of the 

 steam-engines required to drive the dynamos. 

 The steam-engine, although much the senior of 

 the dynamo in the list of inventions, is not nearly 

 so well understood. It is but very recently that 

 the laws of condensation and expansion of steam 

 in the engine actually at work have been grasped, 

 and our limitations so clearly denned as to point 

 out the logical way to greater economies, and pre- 

 vent us from attempting economy under impos- 

 sible conditions. 



— The photograph of the normal solar spec- 

 trum, made by Prof. H. A. Rowland at the Johns 

 Hopkins university, Baltimore, is now complete 

 from wave-length 3680 to 5790 ; and the portion 

 above 3680 to the extremity of the ultra-violet, 

 wave-length about 3100, is nearly ready. Nega- 

 tives have also been prepared down to and includ- 

 ing B, and it is possible they may be prepared for 

 publication. The plates, seven in number, all 

 contain two strips of the spectrum, except No. 2, 

 which contains three. They are three feet long 

 and one foot wide. These can now all be fur- 

 nished to order except No. 2, the negative of 

 which is being made. The plates will be delivered 

 in Baltimore or New York, or will be sent by 

 express or mail, securely packed, at the charge 

 and risk of the purchaser, at the following net 

 prices : the set of seven plates, unmounted, $10 ; 

 mounted on cloth, $12 ; single plates, $2 each ; 

 mounted on cloth, $2.25. 



— A telegram from Guayaquil, of Jan. 20, an- 

 nounces that indications of an earthquake were 

 observed in Chimbo contemporary with a re- 

 newed outbreak of the Cotopaxi volcano. 



— There are good reasons for supposing that a 

 bill will pass both houses of congress, appropriat- 

 ing fifteen thousand dollars annually to Cornell 

 university for the establishment of an agricultural 

 experiment-station at that institution. 



— The Norwegian ship Ferdinand at Philadel- 

 phia reports that near midnight of Jan. 8, in lati- 

 tude 38° 20' north, longitude 71° 20' west, during 

 a severe storm of rain and wind, the night being- 

 very dark, all the yard-arms and mastheads 

 were suddenly lighted up with St. Elmo's fire, 

 having the appearance of bright lanterns. The 

 phenomenon lasted about three minutes. 



— The opening of the third electrical exhibition 

 at St. Petersburg, which took place on Jan. 1, is 

 attracting much attention among the people, 

 especially that portion devoted to the telephone. 

 The exhibition is said to be noteworthy for the 

 novelty, variety, and number of its objects. For 

 illumination, all the known systems of electrical 

 lighting are employed. 



— The Kolnische zeitung for Jan. 14 states that 

 at the preceding meeting of the Vienna geographi- 

 cal society was announced the discovery, by Dr. 

 Stapf, of a hitherto unknown lake in the Persian 

 desert. The lake, according to Dr. Stapf, is at 

 least forty kilometres long, and is probably of 

 recent origin. According to information obtained 

 from Mohammedan sources, it appears that the 

 lake dried up after a previous existence, and later 

 re-appeared. The water is to a very considerable 

 degree alkaline. 



LETTERS TO THE EDITOR. 



*** Correspondents are requested to be as brief as possible. The 

 writer's name is in all cases required as proof of good faith. 



The competition of convict labor. 



The two articles which have appeared in Science on 

 this problem (vii. Nos. 153 and 155) by Mr. N. M. 

 Butler treat this subject after the manner of that 

 system or school of political economy which is taught 

 in the colleges, and which rules in business. Its aim 

 and end is profit. It is science ' for revenue only,' 

 and it ignores morality or humanity. It judges all 

 human activity by the standard of profitableness. 

 In reference to this particular question, Mr. Butler 

 formulates that stand-point very characteristically 

 by the following initiatory axiomatic phrase : £< That 

 convicts should be employed, if possible, in a manner 

 profitable to the state, is a proposition that no sane 

 man controverts." 



To be sure, any thing humane is sentimental non- 

 sense to this school ; and any thing so ' unbusinesslike ' 

 as the greatest of virtues, charity, is insanity. But 

 this form of ' insanity ' is increasing rapidly in the 

 world, and developing a new school of political econ- 

 omy, whose central principle is to further the welfare 

 of all men. From the stand-point of tbat school, a 

 prison should not be a slave-pen for grinding out 

 ' profit ' to the state, but either a refuse for moral 

 cripples or a school for those who lack the moral 

 training necessary to make them good citizens. 



About the cause of the agitation of this question 

 among workingmen, Mr. Butler makes some state- 



