Morning journal and courier., 1883-09-01
A Scientific Explanation

l
 Several weeks ago we inadvertently stated
 in these columns that a man weighing 15O
 pounds on the earth would weigh 4, 800 pounds on the planet Jupiter. When we venture on weighty and scientific statement 1 like that we generally mean what we say, and are prepared with the Indian clubs and l dumb bells of truth to back up any assertion 1 we may make.
 In this case, however, we must acknowl- ] edge that the statement was not based on our l own actual experience. We have never had | the leisure to take a hundred nd-f1fty-pound 1 man to Jupiter and have him weighed. In l stead of this we confded too much in the l word of the astronomical editor of the Pop
 ular Science Monthly for the truth of the statement. A correspondent addresses us as | follows:
 1T notice an incorrect statement in the | last number of Siftings and, as I have seen the same before in other papers, thought it states that man weighing 15O pounds on
 the earth would weigh 1, 500 pounds on Jupi ter. Now, the amount of attraction that any body exerts over another is directly as the
 mass of the body, and inversely as the
 square of the distance between them. The
 diameter of Jupiter is about eleven times
 that of the earth, hence it's volume is about j, 300 times as much as the volume of the
 earth, and as the density is about one-fourth
 that of the earth, the mass of Jupiter is somewhere near three hundred times the
 mass of the earth. As the attraction varies
 directly as the mass, and inversely as the
 square of the distance, we have for the at
 traction of Jupiter as compared with the at
 traction of the earth about 2.5. That Is, if
 the surfaces of the earth and Jupiter had the same velocities of rotation, 8 man weighing
 150 pounds on the earth would weigh 375 pounds on Jupiter. But Jupiter revolyes in about ten hours and, as it's circumference is eleven times the circumference of the earth, the velocity of its surface Is about twenty six times the velocity of rotation of the sur face of the earth. This created velocity would give rise to much greater centrifugal force, diminishing the weight of every body about one-half. If this is taken into account, the weight of body on the surface of Jupi- ter at the equator will be found to be but little greater than it is on the surface of the earth, provided the same latitude is taken on both planets"
 This is rapidly making small potatoes of @ man, and 1t pains us to think that our care- lessoess in suddenly assuming that the Popu- lar Science man was infaliible, and printing the statement without taking the calculation home, and wrestling with 1t in secret sorrow and travail of spirit, has been the innocent cause of leading thousands of hard-working and honest 150 pound people to believe that they would actually weigh 4, 800 pounds each if they could only get aboard Jupiter To any of our readers who have been going around during the late hot weather. and bragging that on the planet Jupiter they would weigh somewhere in the neiohborhood of two tons and quarter, we apoloQize. They would not weigh anything of the kind There is something the matter, as our corre- spondent shows, with Jupiter's inverse ratio,