Page:Popular Science Monthly Volume 18.djvu/789

Rh been B A. Then for any year from 1800 to 1899 the number of letters used equals the number of years $$+$$ the number of years (that number being leap-years) $$-$$ 14 for centurial years which are not leap-years. This number divided by 7 gives the number of times all the letters have been used, and if the remainder is the dominical letter is the same as that of the year 0, i, e., A (from March). Any remainders, 1, 2, 3, etc., will give corresponding letters, G, F, E, etc., as in the years 1, 2, 3, etc., Upon the same principle the dominical letter for the years of any other century can be found. But, as the number to be deducted for centurial years, not leap-years (equal 14), is an exact multiple of 7, the remainder will be the same whether it is deducted or not, and hence no account need be made of it, for it is by the remainder and not by the quotient that the Sunday letter is fixed. The above-mentioned rule will, therefore, not answer for any century but this one until the twenty-eighth century, when it can again be used, because the centurial number to be deducted will then be 21, which, being also a multiple of 7, may be disregarded.

In addition to these tables, another was constructed showing at a glance what letter corresponds to any day of the year; but, as this table is cumbersome and unwieldy, a device has been substituted which is very simple and answers all the purposes of a table. The letter for the first day of every month is always the same. These letters being known, together with the Sunday letter for any year, we can readily find what the first day of any month is, and consequently what day of the week any other day of the month is. The letters for the first of each are as follows, beginning with January: A, D, D, G, B, E, G, C, F, A, D, F, and, to assist the memory in retaining them, they have been woven into the following couplet:

 

T is related, as a legend of the medical fraternity, that the Emperor Augustus was once so highly pleased at a cure effected in himself by his doctor, Antonius Musa, that he raised that gentleman to the rank of knight, and relieved the whole profession from the burdens of taxation.

Probably at no time before or since that event has the lot of the physician been such a happy one. In the earlier days of Rome the  Rh