The poet, seeing by the heart, realises the inexpressible and strived to give it expression. His imagination soars, where the sight of others fails, and his news of realm unknown finds voice in rhyme and metre. The path of the scientific man may be different, yet there is some likeness between the two pursuits. Where visible light ends, he still follows the invisible. Where the note of the audible reaches the unheard, even there he gathers the tremulous message. That mystery which lies behind the expressed, is the object of his questioning also; and he, in his scientific way, attempts to render its abstruse discoveries into human speech. This vast abode of nature is built in many wings, each with its own portal. The physicist, the chemist, and the biologist entering by different doors, each one his own department of knowledge, comes to think that this is his special domain, unconnected with that of any other. Hence has arisen our present rigid division of phenomena, into the worlds of the inorganic, vegetal, and sentient. But this attitude of mind is philosophical, may be denied. We must remember that all enquiries have as their goal the attainment of knowledge in its entirety. The partition walls between the cells in the great laboratory are only erected for a time to aid this search. Only at that point where all lines of investigation meet, can the whole truth be found. Both poet and scientific worker have set out for the same goal, to find a unity in the bewildering diversity. The difference is that the poet thinks little of the path, whereas the scientific man must not neglect. The imagination of the poet has to be unrestricted. The intuitions of emotion cannot be established by rigid proof. He has, therefore, to use the language of imagery, adding constantly the words 'as if.' The road that the scientific man has to tread is on the other hand very rugged, and in his pursuit of demonstration he must pay a severe restraint on his imagination. His constant anxiety is lest he should be self-deceived. He has, therefore, at every step to compare his own thought with the external fact. He has remorselessly to abandon all in which these are not agreed. His reward is that he gets, however little is certain, forming a strong foundation for what is yet to come. Even by this path of self-restraint and verification, however, he is making for a region surpassing wonder. In the range of that invisible light, gross objects cease to be a barrier, and force and matter become less aesthetic. When the veil is suddenly lifted, upon the vision hitherto unsuspected, he may for a moment lose his accustomed self-restraint and, exclaim "not 'as if'--but the thing itself!" INVISIBLE LIGHT.