This is still more the case in Mechanics, Astronomy, {328} and pure mathematics. In these sciences, several of the primary stages of generalization being already passed over, when any new steps are made, we have before us some analogy by which we may frame our new terms. Thus when the _plane of maximum areas_ was discovered, it had not some new arbitrary denomination assigned it, but the name which obviously described it was fixed as a technical name. The result of this survey of the scientific terms of recent formation seems to be this;--that indigenous terms may be employed in the descriptions of facts and phenomena as they at first present themselves; and in the first induction from these; but that when we come to generalize and theorize, terms borrowed from the learned languages are more readily fixed and made definite, and are also more easily connected with derivatives. Our native terms are more impressive, and at first more intelligible; but they may wander from their scientific meaning, and are capable of little inflexion. Words of classical origin are precise to the careful student, and capable of expressing, by their inflexions, the relations of general ideas; but they are unintelligible, even to the learned man, without express definition, and convey instruction only through an artificial and rare habit of thought. Since in the balance between words of domestic and of foreign origin so much depends upon the possibility of inflexion and derivation, I shall consider a little more closely what are the limits and considerations which we have to take into account in reference to that subject. APHORISM XXI. _In the composition and inflexion of technical terms, philological analogies are to be preserved if possible, but modified according to scientific convenience._