Page:Popular Science Monthly Volume 44.djvu/837

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MONO the various penalties entailed by ill-health, a not infrequent one is the inability to pay the last honors to a valued friend; and sometimes another is the undue postponement of such tribute to his memory as remains possible. Of both these evils I have just had experience.

It was, I think, in 1852 that Prof. Tyndall gave at the Royal Institution the lecture by which he won his spurs: proving, as he then did, to Faraday himself, that he had been wrong in denying diamagnetic polarity. I was present at that lecture; and when introduced to him very shortly after it, there commenced one of those friendships which enter into the fabric of life and leave their marks. Though both had pronounced opinions about most things, and though neither had much reticence, the forty years which have elapsed since we first met witnessed no interruption of our cordial relations. Indeed, during recent years of invalid life suffered by both of us, the warmth of nature characteristic of him has had increased opportunity for manifesting itself. A letter from him, dated November 25th, inquiring my impressions concerning the climate of this place (St. Leonards), raised the hope that something more than intercourse by correspondence would follow; but before I received a response to my reply there came the news of the sad catastrophe.

I need not dwell on the more conspicuous of Prof. Tyndall's intellectual traits, for these are familiar to multitudes of readers. His copiousness of illustration, his closeness of reasoning, and his lucidity of statement, have been sufficiently emphasized by others. Here I will remark only on certain powers of thought, not quite so obvious, which have had much to do with his successes. Of these the chief is "the scientific use of the imagination." He has himself insisted upon the need for this, and his own career exemplifies it. There prevail, almost universally, very erroneous ideas concerning the nature of imagination. Superstitious peoples, whose folklore is full of tales of fairies and the like, are said to be imaginative; while nobody ascribes imagination to the inventor of a new machine. Were this conception of imagination the true one, it would imply that, whereas children and savages are largely endowed with it, and whereas it is displayed in a high degree by poets of the first order, it is deficient in those having intermediate types of mind. But, as rightly conceived, imagination is the power of mental representation, and is measured by