My dear Sir.

the glasses which I sent you—are not those named in the Researches as the three—effective respectively in accelerating germination—lignification and floriation.¹ For the former an intense Cobalt blue glass is required—for the 2^nd. a Silver Yellow—and for the 3^rd a deep Copper Red. I mean the glasses should be of the fullest tint which those metals will give. If you would write M. Bontemps at Messrs Chance Brothers—Glass Works, Birmingham² and state the Size—and the character of the glasses you desire to have, I have no doubt he would immediately send them you— You may use my name in writing.

Unfortunately my duties will carry me out of Town this week—and I shall be absent for some time—but any letter sent to the Museum³ will be forwarded to me—and I shall have the greatest pleasure in aiding you to the utmost in your experiments— Since I am not likely to renew them for many years, if ever, I am much pleased to find them taken up by one so well able to investigate this interesting subject

I am | My dear Sir | Yours most truly | Robert Hunt Ch^s Darwin Esq^r