The objects of this work, which is entitled The Wisdom of God manifested in the Works of the Creation, were, 1st, To demonstrate the existence of a Deity; 2dly, To illustrate some of his principal attributes; 3dly, "To stir up and increase in us the affections and habits of admiration, humility, and gratitude." Like many excellent theological treatises of former times, it is now less frequently read than it deserves to be. Happily, however, we have volumes of more recent date, which inculcate the same principles, with perhaps more accuracy of detail in all that relates to science. From a passage in it we learn what was his conception of the true character of a naturalist: "Let it not suffice us," says he, "to be book-learned, to read what others have written, and to take upon trust more falsehood than truth. But let us ourselves examine things as we have opportunity, and converse with nature as well as books. Let us endeavour to promote and increase this knowledge, and make new discoveries, not so much distrusting our own parts, or despairing of our own abilities, as to think that our industry can add nothing to the invention of our ancestors, or correct any of their mistakes. Let us not think that the bounds of science are fixed like Hercules' pillars, and inscribed with a ne plus ultra. Let us not think we have done when we have learnt what they have delivered to us. The treasures of nature are inexhaustible. Here is employment enough for the vastest parts, the most indefatigable industries, the happiest opportunities, the most prolix and undisturbed vacancies."
As a specimen of the author's manner and reasoning, we may present a passage in which he refutes the opinion of Descartes, that it were an absurd and childish thing, and a resembling of God to a proud man, to assert, that he had made the world, and all the creatures in it, for his own honour. "It is most reasonable that God Almighty should intend his own glory: For he being infinite in all excellencies and perfections, and independent upon any other being, nothing can be said or thought of him too great, and which he may not justly challenge as his due; nay, he cannot think too highly of himself, his other attributes being adequate to his understanding; so that, though his understanding be infinite, yet he understands no more than his power can effect, because that is infinite also. And, therefore, it is fit and reasonable, that he should own and accept the creatures' acknowledgments and celebrations of those virtues and perfections, which he hath not received of any other, but possesseth eternally and originally of himself. And, indeed (with reverence be it spoken), what else can we imagine the ever-blessed Deity to delight and take complacency in for ever, but his own infinite excellencies and perfections, and the manifestations and effects of them, the works of the creation, and the sacrifices of praise and thanks offered up by such of his creatures as are capable of considering those works, and discerning the traces and footsteps of his power and wisdom appearing in the formation of them; and, moreover, whose bounden duty it is so to do. The reason why man ought not to admire himself, or seek his own glory, is, because he is a dependent creature, and hath nothing but what he hath received; and not only dependent, but imperfect; yea, weak and impotent: And yet I do not take humility in man to consist in disowning or denying any gift or ability that is in him, but in a just valuation of such gifts and endowments, yet rather thinking too meanly than too highly of them; because human nature is so apt to err in running into the other extreme, to flatter itself, and to accept those praises that are not due to it; pride being an elation of spirit upon false grounds, or a desire and acceptance of undue honour. Otherwise, I do not see why a man may not admit, and accept the testimonies of others, concerning any perfection, accomplishment, or skill, that he is really possessed of; yet can he not think of himself to deserve any praise or honour for it, because both the power and the habit are the gift of God: And considering that one virtue is counterbalanced by many vices, and one skill or perfection with much ignorance and infirmity."
This book obtaining general approbation, the impression, which consisted of 500 copies, was quickly sold off. A new edition was therefore published, and several others succeeded. Encouraged by this success, he prepared for the press his Three Physico-theological Discourses, concerning the Chaos, Deluge, and Dissolution of the World, the substance of which had been embodied in some sermons which he preached before the university. This work has also gone through several editions. In the opinion of the illustrious Cuvier, it affords "a system of geology as plausible as any of those which had appeared at this period, or for a long time afterwards;" and if it contain facts and arguments which are not now admitted as accurate or conclusive, this, with our experience of like defects in other theories, should teach us to moderate our zeal in defending any hypothesis elicited from the partial examination of that complex system, which, being the work of infinite power and wisdom, cannot be thoroughly understood by minds constituted like ours.
In one of these works is an estimate of the number of animals and plants known in Ray's time, to which it is of importance that we should advert, as it furnishes an interesting fact in the history of science. According to the author's classification, animate bodies are divided into four orders, "beasts, birds, fishes, and insects." The number of beasts, including also serpents, that had been accurately described, he estimates at not above 150, adding that, according to his belief, "not many, that are of any considerable bigness, in the known regions of the world, have escaped the cognizance of the curious." At the present day, more than 1000 species have been described. The number of birds, he says, "may be near 500; and the number of fishes, secluding shell-fish, as many: but, if the shell-fish be taken in, more than six times the number." As to the species remaining undiscovered, he supposes "the whole sum of beasts and birds to exceed by a third part, and fishes by one-half, those known." The number of insects, that is, of animals not included in the above classes, he estimates at 2000 in Britain alone, and 20,000 in the whole world. The number of plants described in Bauhin's Pinax was 6000, and our author supposes, that "there are in the world more than triple that number; there being in the vast continent of America as great a variety of species as with us, and yet but few common to Europe, or perhaps Africk and Asia. And if," says he, "on the other side the equator, there be much land still remaining undiscovered, as probably there may, we must suppose the number of plants to be far greater."—"What," he continues, "can we infer from all this? If the number of creatures be so exceeding great, how great, nay immense, must needs be the power and wisdom of Him who formed them all!"
Early in 1692, the Synopsis Methodica Animalium Quadrupedum et Serpentini Generis was finished, and published the year after. Important as were the botanical writings of Ray, his zoological works have had a more decided influence on the advancement of natural history. "Their peculiar character," says Cuvier, "consists in clearer and stricter methods than those of any of his predecessors, and applied with more constancy and precision. The divisions which he has introduced into the classes of quadrupeds and birds have been followed by the English naturalists almost to our own day; and we find very evident traces of his system of birds in Linnæus, Brisson, Buffon, and all the authors who have treated of that class of animals." In the Synopsis of Four-footed animals and Serpents, he commences with an interesting discussion respecting the nature and faculties of animals. The definition, however, on which he proceeds is scarcely correct, or at least sufficiently distinctive:—"An animal is an animated body, endowed with sense and spontaneous motion, or rather with the faculty of feeling and moving, although it may not change place." In treating of the generation of the lower species, he discusses the subject of spontaneous or equivocal origin, the idea of which he refutes, and endeavours to prove that all animals were created at one time. The division of them into viviparous and oviparous he rejects, alleging, that all are in one sense or other oviparous. The most suitable primary division, he says, is into blooded and bloodless, or, as we should say, red-blooded and white-blooded. The former may be divided into those which respire by lungs, and those which respire by gills. The first of these are again divided into such as have two ventricles to the heart, and such as have only one. Animals with two ventricles are viviparous, as Quadrupeds and Cetacea, or oviparous, as Birds. Those having a heart furnished with a single ventricle, are the Oviparous Quadrupeds, and serpents. Animals that respire by gills are the true Fishes, not including whales. The white-blooded animals are divided into the larger and the smaller. The former, he says, are suitably divided by Aristotle into three kinds or orders: 1. Mollusca; 2. Crustacea; 3. Testacea. The smaller white-blooded animals are the Insects. The following table exhibits a summary of this classification, which is essentially that of Aristotle:—
| Red-blooded Animals. | |
| Respiring by lungs, and having a heart furnished with two ventricles, viviparous, and aquatic, | Cetacia. |
| Terrestrial, | Quadrupeds. |
| Oviparous, | Birds. |
| Those having a heart with a single ventricle, | Oviparous Quadrupeds, and Serpents. |
| Respiring by gills, | Fishes. |
| White-blooded Animals. | |
| {Malacia or Mollusca. | |
| Of large size, | {Malacostraca or Crustacea. |
| {Ostracoderma or Testacea. | |
| Of small size, | Insects. |
Characterizing the different groups by circumstances connected with their organization, he arranges quadrupeds into those which have undivided hoofs, as the horse; those having cleft hoofs, of which some are ruminant, others not. Of the former, some have permanent concave horns, as oxen, sheep, goats; others have solid deciduous horns, as deer. The cloven-footed animals which do not ruminate are the hog family. The rhinoceros, hippopotamus, tapir, and musk, he classes as anomalous. Of the unguiculate animals, some are ruminant, with two claws only, as the camel; others are carnivorous, with more numerous claws, as cats, dogs, polecats. Some again are herbivorous, with two long front teeth, as hares; and others are toothless, as the anteater. Other animals of this kind are furnished with wings, and have a short muzzle, as the bats; while some are without wings, as the sloth. Tortoises, lizards, and serpents, bring up the rear.
After this work had been published, he completed a Synopsis of Birds and Fishes, which was sent to Dr Robinson to be printed; but the booksellers who had the copyright neglected it, so that it did not appear until after the author's death, when it was enlarged and edited by Derham in 1713.
Having finished these synopses, Mr Ray considered his labours at an end,—a consummation which gave him the more joy, because he had for several years suffered severely in his health. But soon after, he was induced to add to an English translation of Rauwolf's Travels "three Catalogues of such trees, shrubs, and herbs, as grow in the Levant." His next publication was the Catologus Stirpium in Exteris Regionibus Observatarum, consisting of species not growing spontaneously, or at least very rarely seen, in Britain. Having taken occasion in this work to criticize the method of Rivinus, this circumstance gave rise to some literary altercation, the result of which was a more careful revisal of his system, and a republication of his Methodus Plantarum Nova. At this period he was so tormented by a continual diarrhœa and painful ulcers in his legs, which kept him sleepless for whole nights, that he could not walk into the fields, much less visit the botanic gardens, where he might have found materials for his work.
His booksellers being unwilling to incur the pecuniary hazard attending this work, it was transmitted by Mr Ray to his friend Dr Hotton, professor of botany at Leyden, who got it printed in 1703. The Dutch publishers inserted in the titlepage that it was printed at London for Smith and Walford, the persons who usually took charge of his books; and although the author objected to this proceeding they disregarded his wishes, alleging, that "it was customary among the printers to say what they thought would be for their interest in such cases." This production was very favourably received on the Continent, and Hotton used it as his text-book.