In the second book of the Novum Organum, lord Bacon proceeds to develop more fully his inductive method, and to exemplify it; selecting for this purpose the subject of Heat. From what has been already said, it is obvious that, in every subect of inquiry, the first step is to collect such facts or phenomena as in any way relate to it, not only those which spontaneously offer themselves, but such as can be elicited by experiment.

In this preliminary procedure, more skill and judgment are required than those unused to scientific pursuits will be prepared to expect.

It often happens that an object is not seen, from not knowing how to see it, rather than from any defect in the organ of vision. Mr. Babbage has given a striking illustration of this fact. Conversing with sir John Herschel on the dark lines observed in the solar spectrum by Fraunhofer, he inquired whether Mr. Babbage had seen

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them; and on his replying in the negative, sir John Herschel mentioned the extreme difficulty he had had, even with Fraunhofer's description in his hand, and the long time which it had cost him in detecting them: he then added, 'I will prepare the apparatus, and put you in such a position that they shall be visible, and yet you shall look for them and not find them: after which, while you remain in the same position, I will instruct you how to see them, and you shall see them, and not merely wonder you did not see them before, but you shall find it impossible to look at the spectrum without seeing them.' On looking as he was directed, notwithstanding the previous warning, Mr. Babbage did not see them; and, after some time, he inquired how they might be seen, when the prediction of sir John Herschel was completely fulfilled.* But if it be some

* Babbage's Reflections on the Decline of Science in England, pp. 210, 211.

times difficult to see an object, from not knowing how to see it, there is another obstacle of much more frequent occurrence, which all who are engaged in the study of nature must strictly guard against, viz. the proneness of observers, especially if they are illiterate, to record their remarks in theoretic language.* Many curious and interesting data have, on this account, been rendered worse than useless, for they have misled. Science, too, has sometimes suffered,

* See Stewart's Philosophy, pp. 467, 468, and Playfair's Prelim. Diss. to Ency. Brit. p. 559. ‹ If you will be at the pains carefully to analyse the simplest descriptions you hear of any transaction or state of things, you will find, that the process which almost invariably takes place is, in logical language, this; that each individual has in his mind certain major-premises or principles, relative to the subject in question; that observation of what actually presents itself to the senses supplies minor-premises; and that the statement given (and which is reported as a thing experienced) consists, in fact, of the conclusions drawn from the combinations of those premises.'-Whately's Lectures on Political Economy, p. 76.

from the frauds of observers: but, fortunately, this is of rare occurrence. The supposititious discovery of the Gioenia Sicula, by M. Gioeni, a knight of Malta, is, however, a good lesson on this subject, and will not be soon forgotten. Having, therefore, obtained an authentic and genuine collection of facts, described in terms which involve no theory or hypothesis, the next step is, by a comparison of these facts, to discover what Bacon calls the form of the particular subject of inquiry. In his Advancement of Learning, he remarks that Plato, who 'had a wit of elevation situate as upon a cliff,' did descry that forms are the true subject of knowledge; but adds, that he lost the real fruit of his opinions by considering them as mere abstractions, and not confined and determined (as in fact they are,) by matter.* From another passage (in the Novum Orga

* Bacon's Works, vol. 2, pp. 136, 137; De Augment. Scient. lib. iii cap. iv. See Coleridge's Friend, vol. 3, pp. 204-216.

num*,) it appears that Bacon uses the word forms as synonymous with laws of nature;

and he seems to have entertained the lofty hope that the inductive method, if assiduously applied, would lead us to a knowledge of the essences of the properties or qualities of matter; as, for instance, the essence of heat, of colour, or of cold. It was natural, however,' says Professor Playfair, ‘that Bacon, who studied these subjects theoretically, and saw nowhere any practical result in which he could confide, should listen to the inspirations of his own genius, and ascribe to philosophy a perfection which it may be destined never to attain.'†

Having, agreeably to the precepts of Bacon, brought together all ascertainable facts relative to the phenomenon whose form, i. e. cause or law is the object of inductive inquiry, we must begin with consider

* Lib. ii. aph. xvii.

+ Playfair's Prelim. Diss. p. 474.