To the Editor of the Daax Siz,—Some time ago Mr. von Gam-ach covered a lange space of the columns of your paper with what he termed an account of 'a species of mathematical revolving storm" that bad "lately risen on these coasts." The origin of this phenomenon was a rule for determining "prime numbers, discovered by Mr. Lo, native professor of mathematics in the Peking Univer-y. Not content, however, with a mero description of this "harmless form of typhoon," Mr. von Gumpach gave also a practical illustration, which was of such a sweeping character that not a word has since appeared either for or against Mr. Io's rule. The subject, far from being exhausted. Another of these storms has been brewing in a different quarter; and in order that it may have full play, a'place is now asked for it in your It will perhaps be remembered that Mr. Lo showed his rule to a few of his Foreign friends, asking if anything similar was known among Western mathematicians, Having found its way into Notes and Queries on China and it was rather severely attacked by rent correspondents to that publication. First comes an effusion from Mr, vou Gumpach, (yo. 3 No. 10) in which he be labours both Mr. Lo and his rule, with a vigour worthy of the prowess of a philosopher already more than a match for Newt: His criticism is to the effect that Mr. uncouth formula" is merely an "empirical deduction" obtained from "trials with a few low numbers that its enunciation is defective; that he has not seized its principle; that he attaches an undue value to it; that he cannot demonstrate it cither mathematically or logically, any more than can Mr. von Gumpach himself; and. in short that the rule is unfit for all practical pu Then follows Mr. r of Amoy (vol. 3, No ho shows that the rule as enunciated by Mr. von Gumpach is not strictly accurate; that its approximate accuracy depends on a well known theorem in elementary algebra; and that it of course possesses no special value."
Text read from the printed page and cleaned; old type leaves the occasional error.