(From Obituary Notice of Rev. W. V. V. Harcourt, Roy. Soc, Proc, Vol. 20, 1872. By Prof. Phillips?)

Accustomed to the use of the gas-furnace, Mr Harcourt turned it to experiments on transparent compounds of fusion, which might be made to have refractive indices beyond the ordinary ranges, combined with scales of dispersion more favourable to achromaticity. In this he was guided by the trials of Faraday to prepare glass for optical purposes. Many years since, the writer, who was often helpful in this way, ground one of the earliest of the Harcourt glasses into a lens, and found it indeed a highly refractive clear substance, but too much traversed by striæ to be of practical use.

When, some years since, Mr Harcourt removed his residence to the family seat at Nuneham, near Oxford, he constructed furnaces of a different kind for the carrying on of these experiments, and followed them with the zeal, resolution, and patience which had always characterized his firm and well-regulated mind. At an age when most men cease from continuous literary and scientific work, he with failing sight, but perfect memory, was indefatigable in training an assistant and superintending his work; making many new combinations with substances untried before, and now selected for quality of fusion, resistance to atmospheric vicissitudes, range of refraction and specific action on different rays of the spectrum. Thus it was hoped finally to acquire glasses of definite and mutually compensative dispersions, so as to make perfectly achromatic combinations.