CH. XVII.

ZOOLOGY.

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From 1663 to 1666 the two friends travelled together over England, France, Germany, and Italy, making collections of animals and plants, and Willughby took a pleasure in using his wealth to add to the knowledge of his poorer companion. Soon after their return Ray was made a fellow of the Royal Society, and Willughby was not long before he received the same honour. Willughby now married, and though Ray continued his travels alone, yet a great part of his time was spent at Middleton Hall, where the two friends made experiments upon sap in the trees and the way it flows.

In this way they worked together till, in 1672, 'Mr. Willughby died of a fever, leaving a sum of sixty pounds a year to Ray, and begging him to bring up his two little sons and to continue his works on Zoology, which he had left unfinished. The way in which Ray fulfilled these requests fully showed the affection which he felt for his lost friend. Не brought up the boys till they were removed from his care by relations; and as to the works, he edited them with so much care and such a touching desire to give every credit to Willughby, that much of the work which must have been Ray's stands in his friend's name, and in fame, as in life, it is impossible to separate them..

I can only give you a very general idea of the kind of classifications which Ray and Willughby adopted, for a mere list of classes would be neither interesting nor useful to you. The first book, which was on Quadrupeds, was published by Ray in 1693. He divided these first, as Aristotle had done, into oviparous, or those that are born from eggs, like frogs and lizards; and viviparous, or those which are born alive, like lambs and kittens. He then divided the viviparous quadrupeds into those which have the hoof all in one piece,

like the horse, and those with a split hoof, like the ox and goat. Those with split hoofs he divided again according as they chewed the cud, like the ox, or did not, like the pig. Then came the animals whose hoofs are split into many parts, as the hippopotamus and rhinoceros ; then those which have nails only in place of toes, as the elephant; then those which have toes but no separation between the fourth and fifth toes, as the cat, dog, and mole; and lastly, those which have the fifth finger, or toe, quite separate, as the monkeys. After this he divided them more fully, by their teeth, and thus made a very fair classification of quadrupeds.

The book upon Birds, which comes next in order, had already been published by Ray in 1677, four years after Willughby's death. In it birds were divided first into landbirds and water-birds, and then were classified by the shape of their beak and claws, and according as they fed upon flesh like the vulture, or upon fruit and seeds like the parrot. The water-birds were also divided into those which were longlegged, as the flamingo, or short-legged, as the duck, and according as the web between their toes was more or less complete.

The 'History of Fishes' is given as the joint work of Ray and Willughby; the groups into which they divided them are nearly the same as those now used, but they are too difficult to explain here.

6

The History of Insects' was Ray's work, and was published by friends after his death, in the same way as he had published Willughby's. He divided insects into-first, those which undergo metamorphosis (that is, turn from the caterpillar into the moth), as the silkworm, and all moths and butterflies; and second, those which do not change their form; and then he sub-divided them according to the number of their feet, the shape of their wings, and many other characters.

CHI. XVII. RAY'S CLASSIFICATION OF PLANTS.

145

But Ray's greatest work was upon Plants, which he classified much more perfectly than Casalpinus had done. He divided them first into imperfect plants, or those whose flowers are invisible, as mosses and mushrooms; and perfect plants, or those having visible flowers. The perfect plants he divided into two classes-first, the dicotyledons, or those whose seeds open out into two seed-leaves, like the wallflower or the bean, in which last you can see the two cotyledons very clearly if you take off the outer skin; and secondly, the monocotyledons, or those whose seeds have only one large seed-leaf, like a grain of wheat. The dicotyledons he again divided into those having simple flowers, like the buttercup, and those whose flowers are compound, like the daisy; for if you pick a daisy to pieces you will find that the centre is made up of a number of little flowers, each of them perfect in itself. It will have its own green calyx and coloured corolla, and its own stamens and seed-vessel; therefore each daisy is a branch of little flowerets, or a compound flower. Ray went on next to class the simple flowers according to the number of seeds they bore, and the way in which the seeds were arranged in the seed-vessel. In this way he made a rough but complete classification of all the known plants. Linnæus, the great botanist of the eighteenth century, adopted many of Ray's divisions, which had meanwhile been made more perfect by Joseph Tournefort, a Frenchman, born at Aix, in Provence, in 1656.

Ray outlived his friend Willughby more than thirty years, and died in 1705 at the age of seventy-seven. His death brings us to the end of the Natural History of the seventeenth century, so far as we have been able to notice it. But I cannot too often remind you that these four men, Malpighi, Grew, Ray, and Willughby, are merely a few among an

immense number of observers in the same line of study. I have picked out those whose work you could best understand, and whose names ought to be known to you; but I could have selected not four but forty others who ought to have been mentioned, if my book and your knowledge had been greater. We must be content to catch here and there a glimpse of the advance that was being made, always remembering that an almost inexhaustible store of further information remains behind when we have opportunity to seek for it.

Chief Works consulted.—Cuvier, ‘Hist. des Sciences Naturelles ;' Carpenter's Physiology;' Sprengel, 'Histoire de la Médecine ; ' Whewell's 'History of Inductive Sciences;' Carpenter, 'On the Microscope;' 'Memorial of John Ray,' E. Lankester, 1846; 'Life of Ray and Willughby,' Naturalists' Library, vol. xxxv.; Lardner's 'Encyclopædia'-Classification of Animals.

CH. XVIII.

SIR ISAAC NEWTON.

147

CHAPTER XVIII.

SCIENCE OF THE SEVENTEENTH CENTURY (CONTINUED). 1642, Birth of Newton--His Education-1666, His three great Discoveries first occur to him-Method of Fluxions and Differential Calculus-First thought of the Theory of Gravitation-Failure of his Results in consequence of the Faulty Measurement of the size of the Earth-1682, Hears of Picart's new Measurement-Works out the result correctly, and proves the Theory of Gravitation-Explanation of this Theory-Establishes the Law that Attraction varies inversely as the squares of the distance—1687, Publishes the 'Principia'-Some of the Problems dealt with in this Work.

Newton, 1642.-We must now leave the living creation to return to physical science, for, during all those years with which we have been occupied since the time of Galileo and Kepler, a boy had been growing up into manhood, who was to become one of the greatest men of science that England has ever known. In 1642, the same year in which Galileo died, a child was born at Woolsthorpe, near Grantham in Lincolnshire, who was so tiny that his mother said she could put him into a quart mug.' This tiny delicate baby was to become the great philosopher Newton.

We hear of him that he was at first very idle and inattentive at school, but, having been one day passed in the class by one of his schoolfellows, he determined to regain his place, and soon succeeded in rising to the head of them all. In his play hours, when the other boys were romping, he amused himself by making little mechanical toys, such as a