that of the three thousand souls who listened to Professor Tyndall’s lay sermon there were few who entered into the discussion prepared to embrace his views. Yet we think that there were few also who left that hall at all events without a doubt that the search after truth which is the sole object of the investigation of nature is neither so prosaic nor so dangerous a quest as the false prophets and the Philistines would assert--that philosophy is not ‘harsh and crabbed as dull fools suppose’-- But musical as is Apollo’s lute, And a perpetual feast of nectar’d sweets, Where no crude surfeit reigns. SCIENTIFIC USE OF THE IMAGINATION. [Illustration] I CARRIED with me to the Alps this year the heavy burden of this evening’s work. In the way of new investigation I had nothing complete enough to be brought before you; so all that remained to me was to fall back upon such residues as I could find in the depths of consciousness, and out of them to spin the fibre and weave the web of this discourse. Save from memory I had no direct aid upon the mountains; but to spur up the emotions, on which so much depends, as well as to nourish indirectly the intellect and will, I took with me two volumes of poetry, Goethe’s ‘Farbenlehre,’ and the work on ‘Logic’ recently published by Mr. Alexander Bain.[1] The spur, I am sorry to say, was no match for the integument of dulness it had to pierce. In Goethe, so glorious otherwise, I chiefly noticed the self-inflicted hurts of genius, as it broke itself in vain against the philosophy of Newton. For a time, Mr. Bain became my principal companion. I found him learned and practical, shining generally with a dry light, but exhibiting at times a flush of emotional strength, which proved that even logicians share the common fire of humanity. He interested me most when he became the mirror of my own condition. Neither intellectually nor socially is it good for man to be alone, and the griefs of thought are more patiently borne when we find that they have been experienced by another. From certain passages in his book I could infer that Mr. Bain was no stranger to such sorrows. Take this passage as an illustration. Speaking of the ebb of intellectual force, which we all from time to time experience, Mr. Bain says, ‘The uncertainty where to look for the next opening of discovery brings the pain of conflict and the debility of indecision.’ These words have in them the true ring of personal experience. The action of the investigator is periodic. He grapples with a subject of enquiry, wrestles with it, overcomes it, exhausts, it may be, both himself and it for the time being. He breathes a space, and then renews the struggle in another field. Now this period of halting between two investigations is not always one of pure repose. It is often a period of doubt and discomfort, of gloom and ennui. ‘The uncertainty where to look for the next opening of discovery brings the