Commentary continued; second volume.—Discussion between the English and French mathematicians; Dr. Bowditch’s criticisms.—Errors in La Place in regard to the earth, &c.—Third volume; motions of the moon.—Fourth volume; many errors discovered in it.—Halley’s Comet.—Curious phenomena of capillary attraction.
Commentary continued; second volume.—Discussion between the English and French mathematicians; Dr. Bowditch’s criticisms.—Errors in La Place in regard to the earth, &c.—Third volume; motions of the moon.—Fourth volume; many errors discovered in it.—Halley’s Comet.—Curious phenomena of capillary attraction.
CRITIC OF IVORY AND POISSON.
“I HAVE GOT IT!”
In the second volume of the Commentary, Dr. Bowditch makes very copious notes, in which he shows a perfect knowledge of the works of the chief mathematicians of Europe. He stands as critic between two of the eminent men of science of that day—Messrs. Ivory and Poisson, the former an Englishman, the latter a Frenchman; and in reference, likewise, to a difficult subject, namely, the revolution or the turning of a fluid mass upon its own axis, as our earth does. He not merely agrees with Mr. Poisson, but, by avery simple illustration, proves the total inaccuracy of Mr. Ivory’s views. I well remember the earnestness with which he studied this subject. Day after day, he returned to the task of finding out some “simple case,” with which to prove to the satisfaction of others the truth of his own view. At length, when he did discover it, he jumped up in ecstasy, and, rubbing his hands and forehead with delight, walked about the library-room, crying out, “I have got it!”
Dr. Bowditch in this volume points out five errors or omissions made by La Place, some of which are very important. One refers to the form of our earth, and had been previously communicated to the Academy. There is another of some moment, relative to the time occupied in the revolution of one of Saturn’s rings, La Place having made it longer than was true.
Finally, on the subject of the motion of the earth about its centre of gravity, he points out an error, in which La Place gives to two numbers only one third of their true value.
OLBERS AND GAUSS.
In the third volume, occupied as it is with the motions of the planets and of the moon, and with all the phenomena accompanying these, Dr. Bowditch shows much learning, and his power of bringing modern science to the thorough study of any topic. As in the previous volume, he labors without fear upon subjects treated of with much earnestness by La Place, Poisson, and Pontecoulant, in France, and Plana in Italy.
On the theory of the motions of the moon,—a very difficult and interesting subject,—Dr. Bowditch makes very copious notes; and the volume terminates with an appendix of more than two hundred and fifty pages, in which he gives the history of modern astronomy, in reference to the calculations of the movements of planets and comets. In this he speaks of Olbers and Gauss. The former, from having discovered three planets since the beginning of this century, was called “The fortunate Columbus of the Heavens.” The latter was one of the most remarkable men in the world for the rapidity with which he wasable to perform the most tedious and troublesome calculations.[13]
ERRORS IN LA PLACE.
We come now to the last volume, in printing the thousandth page of which he died. It was the most difficult to him of the whole, and probably will raise him higher, in the estimation of the scientific world, than either of the others. In the first place, I would remark, that either from the difficulty of the subject, or from the inattention of La Place, an unusual number of errors was discovered. No less than twenty-four errors or omissions are pointed out. Many of these seem insignificant, but often, as may be supposed, they materially affect the calculation. Most of them refer to the derangements and the motions of Jupiter’s satellites—a subject which occupies three hundred and fourteen pages of the volume. The keenness of Dr. Bowditch’s criticism is again perceived while treatingupon a subject in dispute between Plana and La Place. Dr. Bowditch points out one mistake, and Poisson another, whereby Plana’s views are proved to coincide entirely with La Place’s, instead of being opposed to them.
NOTE ON HALLEY’S COMET.
I find a note upon Halley’s comet, to which I alluded as presenting a grand spectacle in our western sky a few years since, and I cannot forbear mentioning the coincidence. Dr. Bowditch, when making his notes upon the subject of the motions and revolutions of comets, speaks of Halley’s comet, and mentions all that is known about it, and its probable appearance. This note was prepared some time before it was printed. It terminates thus: “Since writing the preceding part of this note the comet has again appeared, and,at the time of printing this page, is visible in the heavens, not far distant from the place corresponding to the elements of Mr. Pontecoulant.”
CAPILLARY ATTRACTION.
LA PLACE AND POISSON.
The work, so far as Dr. Bowditch is concerned, finishes with the most curious and difficult subject of capillary attraction, or thatpower whereby a liquid rises in narrow tubes beyond the level of the fluid outside, as we see familiarly in sponges, and cloths, and in very minute glass tubes. You may think this subject of little moment; yet La Place thought it more curious than almost any other, and he earnestly calls the attention of mathematicians to it. It is a subject so difficult of investigation, that it requires the keenest efforts of the best intellects to rightly understand it. After La Place’s investigations were published, Gauss considered the subject, and arrived at results similar to those presented by La Place. But in 1831, Poisson, the first mathematician then living, of whom we have already spoken, put forth a work in which he announced many new views. This he thought himself justified in doing, after taking into consideration certain particulars which La Place had neglected. Dr. Bowditch received the work while engaged in printing this volume. He ceased printing, and devoted six months or more to a thorough perusal of the new French work. The result was, that heproved that without an exception, unless where an evident error was made by La Place, the principles of this mathematician, when fairly carried out, would produce all the results which Poisson had given as new in his work. By this labor Dr. Bowditch proved that Poisson’s so-called new theory of capillary attraction was founded in error. This is decidedly the most important work of the translator. It places him much higher than before in the scale of mathematical rank.
I would willingly give a further analysis, but I forbear, because it would not be interesting to you. It was in correcting this, his noblest task, in the full strength of his intellect, that he was destined to die.