Mentions RH’s book on light [Researches on light in its chemical relations, 2d ed. (1854)]. Asks about coloured glass used in experiments on plants.
Mentions RH’s book on light [Researches on light in its chemical relations, 2d ed. (1854)]. Asks about coloured glass used in experiments on plants.
Mentions experiments on plants involving coloured glass. Encloses correspondence from glass maker and asks advice.
Discusses how best to simulate the light at a particular point on the earth’s surface using coloured glass; considers sunlight as composed of three "principles", varying in proportion according to latitude, which affect germination, lignification, and floriation.
Informs CD which colours of glass accelerate germination, lignification, and floriation; advises CD on obtaining such glass and offers his help in any experiments.
Regarding the absence of his own name from the candidates list for the R.S.L.; thinks there is a clique working against him.
Does not believe JH can help RH in some delicate matter. JH talks about photographic chemistry, including passing on information from A. C. Becquerel.