irritability of the muscles and the sensibility of the nerves than with the performance of all the secretions." [119] See vol. i. page 70. The FIFTH DIALOGUE is entitled "The Chemist." Its object is to demonstrate the importance of this noble science. An interlocutor is made to disparage its utility, and to mark its weaker points. These of course are answered, the sceptic becomes a true believer, and the intellectual gladiators separate mutually satisfied with each other. "_Eubathes._--I feel disposed to join you in attacking this favourite study of our friend, _but merely_ to provoke him to defend it, in order to call forth his skill and awaken his eloquence. "_The Unknown._--I have no objection. Let there be a fair discussion: remember, we fight only with foils, and the point of mine shall be covered with velvet." After having enumerated the scientific attainments necessary to constitute the chemist, and described the apparatus essential for understanding what has been already done in the science, he proceeds to define the intellectual qualities which he considers necessary for discovery, or for the advancement of the science. Amongst them, patience, industry, and neatness in manipulation, and accuracy and minuteness in observing and registering the phenomena which occur, are essential. A steady hand and a quick eye are most useful auxiliaries; but there have been very few great chemists who have preserved these advantages through life; for the business of the laboratory is often a service of danger, and the elements, like the refractory spirits of romance, though the obedient slaves of the magician, yet sometimes escape the influence of his talisman, and endanger his person. Both the hands and eyes of others, however, may be sometimes advantageously made use of. By often repeating a process or an observation, the errors connected with hasty operations or imperfect views are annihilated; and, provided the assistant has no preconceived notions of his own, and is ignorant of the object of his employer in making the experiment, his simple and bare detail of facts will often be the best foundation for an opinion. With respect to the higher qualities of intellect necessary for understanding and developing the general laws of the science, the same talents, I believe, are required as for making advancement in every other department of human knowledge; I need not be very minute. The imagination must be active and brilliant in seeking analogies; yet entirely under the influence of the judgment in applying them. The memory must be extensive and profound; rather, however, calling up general views of things than minute trains of thought;--the mind must not be like an Encyclopedia,--a burthen of knowledge, but rather a critical Dictionary, which abounds in generalities, and points out where more minute information may be obtained. * * * * *