difficult to a philosopher, says Adam Smith, he detained it in his closet for thirty years together.  LINNAEUS once in despair abandoned his beloved studies, from a too irritable feeling of the ridicule in which, as it appeared to him, a professor Siegesbeck had involved his famous system.  Penury, neglect, and labour LINNAEUS could endure, but that his botany should become the object of ridicule for all Stockholm, shook the nerves of this great inventor in his science.  Let him speak for himself.  “No one cared how many sleepless nights and toilsome hours I had passed, while all with one voice declared, that Siegesbeck had annihilated me.  I took my leave of Flora, who bestows on me nothing but Siegesbecks; and condemned my too numerous observations a thousand times over to eternal oblivion.  What a fool have I been to waste so much time, to spend my days in a study which yields no better fruit, and makes me the laughing stock of the world.”  Such are the cries of the irritability of genius, and such are often the causes.  The world was in danger of losing a new science, had not LINNAEUS returned to the discoveries which he had forsaken in the madness of the mind!  The great SYDENHAM, who, like our HARVEY and our HUNTER, effected a revolution in the science of medicine, and led on alone by the independence of his genius, attacked the most prevailing prejudices, so highly provoked the malignant emulation of his rivals, that a conspiracy was raised against the father of our modern practice to banish him out of the college, as “guilty of medical heresy.”  JOHN HUNTER was a great discoverer in his own science; but one who well knew him has told us, that few of his contemporaries perceived the ultimate object of his pursuits; and his strong and solitary genius laboured to perfect his designs without the solace of sympathy, without one cheering approbation.  “We bees do not provide honey for ourselves,” exclaimed VAN HELMONT, when worn out by the toils of chemistry, and still contemplating, amidst tribulation and persecution, and approaching death, his “Tree of Life,” which he imagined he had discovered in the cedar.  But with a sublime melancholy his spirit breaks out; “My mind breathes some unheard-of thing within; though I, as unprofitable for this life, shall be buried!” Such were the mighty but indistinct anticipations of this visionary inventor, the father of modern chemistry!

I cannot quit this short record of the fates of the inventors in science, without adverting to another cause of that irritability of genius which is so closely connected with their pursuits.  If we look into the history of theories, we shall be surprised at the vast number which have “not left a rack behind.”  And do we suppose that the inventors themselves were not at times alarmed by secret doubts of their soundness and stability?  They felt, too often for their repose, that the noble architecture which they had raised might be built on moveable sands, and be found only in the dust of libraries; a cloudy