PHYSICAL AND MATHEMATICAL SCIENCES. 143

the true solar year. This difference accumulating everyyear, had amounted to nearly eleven days in the year1582. Thus the equinox which, in Julius Ctcsar’s time,fell on the 21st of March, now took place on the 10th.The Gregorian reformation aimed at two objects: thefirst was that of preventing the accumulation of the dif-ference in future, by ordaining that the concluding yearof the first three out of each four centuries (whichwould have been bissextile) should be a common year,the fourth remaining bissextile. This diminishes thedifference to an amount almost insensible: to make itquite so, Laplace has since suggested leaving the 4000thyear a common year. The second object was to restoreto the equinox the name of the 21st of March, with aview to the regulation of the festivals of the church,especially Easter. Hence the adoption of what w r ascalled the new style, or dating eleven days forward ;what was the 10th of March, being now called the 21st.This gave rise to great confusion, as the states opposedto the Pope ’s authority long refused to adopt it, andtwo styles prevailed. It was not adopted in England till1751 ; nor is it in Russia to this day.

SECTION III.

THE DISCOVERIES OF KEFLER AND GALILEO.

In the period last treated of, we have had occasion tonotice the advances which began to be made in the six-teenth century, in the various parts of the abstract scienceof quantity, and of its application to some of the phe-nomena of the natural world. We have also seen thecommencement of a revolution in opinions on philoso-phical subjects: an opposition beginning to manifestitself against the Aristotelian dogmas, and an increasingdisposition to recur to experiment and observation as the