From this it will be obvious, that nothing can be produced by chance; that no effect can exist without an adequate cause for its existence; that the one must ever be commensurate with the other. All the works of nature grow out of the uniform action of invariable laws, whether our mind can with facility follow the concatenation of the successive causes which operate; or whether, as in her more complicated productions, we find ourselves in the impossibility of distinguishing the various springs which she sets in motion to give birth to her phenomena. To nature, the difficulty is not more to produce a great poet, capable of writing an admirable poem, than to form a glittering stone or a shining metal which gravitates towards a centre. The mode she adopts to give birth to these various beings, is equally unknown to us, when we have not meditated upon it; frequently the most sedulous attention, the most patient investigation affords us no information; sometimes, however, the unwearied industry of the philosopher is rewarded, by throwing into light the most mysterious operations. Thus the keen penetration of a Newton, aided by uncommon diligence, developed the starry system, which, for so many thousand years, had eluded the research of all the astronomers by whom he was preceded. Thus the sagacity of a Harvey giving vigour to his application, brought out of the obscurity in which for almost countless centuries it had been buried, the true course pursued by the sanguinary fluid, when circulating through the veins and arteries of man, giving activity to his machine, diffusing life through his system, and enabling him to perform those actions which so frequently strike an astonished world with wonder and regret. Thus Gallileo, by a quickness of perception, a depth of reasoning peculiar to himself, held up to an admiring world, the actual form and situation of the planet we inhabit; which until then had escaped the observation of the most profound geniuses--the most subtle metaphysicians--the whole host of priests; which when first promulgated was considered so extraordinary, so contradictory to all the then received opinions, either sacred or profane, that he was ranked as an atheist, as an impious blasphemer, to hold communion with whom, would secure to the communers a place in the regions of everlasting torment; in short, it was held an heresy of such an indelible dye, that notwithstanding the infallibility of his sacred function, Pope Gregory, who then filled the papal chair, excommunicated all those who had the temerity to accredit so abominable a doctrine.