EDITOR'S TABLE. 



409 



and transformed into a respectable body of 

 water. These and other hygienic improve- 

 ments which have followed in the wake of 

 the fault-finder will doubtless render Ocean 

 Grove and its close neighbor, Asbury Park, 

 satisfactory places for visitors during the 

 season of 1 883. That the past winter's work 

 is likely to prove efficient may be gathered 

 from Mr. Stokes's letter, in which he says, 

 "The State Board of Health reports that 

 the sanitary matters of the Grove progress 

 satisfactorily." 



It is hoped that the pleasure with which 

 this account is given of a better sanitary 

 prospect for the present summer over that 

 of former years will prove previous charges 

 of improper drainage to have been made 

 only in that spirit which sounds an alarm 

 to prevent danger. 



Alice Hyneman Rhine. 



COST OF LIFE. 



Messrs. Editors: 



In an article in the June number of your 

 magazine, entitled " Cost of Life," there are 

 some mathematical calculations, or rather 

 blunders, that make one wonder how they 

 could have been put forth in any journal, 

 though making less claims to science than 

 your valuable magazine. It is gravely stated 

 that a man weighing 150 pounds upon the 

 earth would, upon the planet Jupiter (hav- 

 ing 300 times the earth's mass), weigh 45,000 

 pounds = 224- tons. The relative mass of 

 Mars is said to be - that of the earth, and, 

 therefore, the man spoken of above would 

 weigh only 2h pounds upon Mars. Now, if 

 the law of attraction as first announced by 

 Newton, and now taught to every schoolboy, 

 is correct, the weight of the above man 

 upon Jupiter would be 2 - 55 (two and -fVfo) 

 times his weight upon the earth = 382^ 

 pounds enough to make him decidedly un- 

 comfortable, but still not quite 22A- tons. 

 In regard to Mars there are two errors : first, 

 his mass is '{- that of the earth, not ,f as 

 stated ; second, if it were ,, it would not 

 be right to divide 150 by 60, for that would 

 disregard a very essential part of the great 

 law or laws of gravitation. If the radius 



of Mars is "52 that of the earth, would not 

 the supposed man weigh, if placed upon his 

 surface, 61 pounds? 



There may be some errors in these cor- 

 rections, but I think they are trifling com- 

 pared with those in Mr. Pratt's article. 

 R. S. Boswokth. 



Wateetown, New York, May 21, 18S3. 



Messrs. Editors : 



Allow me to call attention to certain 

 assertions in the article headed " Cost of 

 Life" in the June number of your journal. 

 The points I speak of relate to gravity on 

 the planets, and the statements made in re- 

 gard thereto. It is declared that a man of 

 150 pounds weight would on Jupiter weigh 

 about 45,000 pounds. It is an elementary 

 truth in physics that gravity decreases as 

 the square of the distance increases ; where- 

 fore, although Jupiter is more than 300 

 times as heavy as the earth, its diameter is 

 more than eleven times that of the earth, 

 and the relative weight must be divided by 

 the square of the ratio. In this case the 

 divisor is more than 121. The best deter- 

 minations of the force of gravity on Jupiter 

 give it at a little less than two and three 

 fourths that on the earth. So the man of 

 150 pounds would, on Jupiter, weigh about 

 400 pounds, not that enormous figure quoted 

 above. 



So, gravity on Mars is more than half 

 that on the earth, and our man would weigh 

 80 pounds, not 2 1 , as given in the article. 

 Every similar statement in the whole course 

 of the discussion is as badly in error as 

 these here noticed. 



It is well known that the destructive 

 effect of a bullet fired by an explosive de- 

 pends not on the power of gravity, but on 

 that of the powder ; and the philosophers 

 who, on Mars, should attempt to catch bul- 

 lets in their hands, might rue their philos- 

 ophy. As science, the article harmonizes 

 well with the kind in which Jules Verne is 

 accustomed to indulge. 



R. W. McFarland. 



Ohio State University, 



Columbus, May 23, 18S3. 



EDITOR'S TABLE. 



THE EACE-DOWy OF DR. DIX. 



OUR friend Dr. Dix lias deserted us. 

 We have received divers sarcastic 

 congratulations upon our new ecclesi- 

 astical alliance, implying that we had 

 made no great acquisition, but we could 

 not anticipate that we should be left in 



the lurch so soon. We were taken with 

 the impressive declamation about the 

 supremacy of the home sphere in the 

 life of woman, and when Dr. Dix said, 

 "These considerations give the turn to 

 every thought of ours about woman's 

 work " and of course the preparation 



