194 COMMUNICATIONS BY 



close arrangement, in which no appearance of insect life had yet 

 been detected. Before removing the open vessel I had, however, 

 the satisfaction to supply therefrom abundance of living specimens 

 to my scientific friends who had kindly interested themselves on 

 the subject, in various parts of England, Scotland, France, and 

 America. 



3. In the beginning of the month of June, 1844, rather more 

 than two years from the commencement of these operations, the 

 solution in the close vessel began to manifest signs of a most 

 remarkable change, the results of constant, slow, and almost in- 

 visible decomposition. The apparatus was carefully tested, and 

 found, as at first, perfectly air-tight, and the confined liquid was 

 evidently returning to a paler red colour, as well as a partially 

 translucent condition. These latter appearances rapidly in- 

 creased, and about the beginning of September in the same year, 

 the solution had acquired a light amber colour and perfect trans- 

 parency, with abundant flakes and scroll- like forms of irregular 

 oxide of iron of a deep orange colour, nearly covering the bottom 

 of the jar. Most of these had, doubtless, been detached in suc- 

 cession from the negative platina spiral, and were conspicuous 

 through the altered solution. It was while engaged in examin- 

 ing this singular accumulation of oxide, by means of an excellent 

 lens, that I saw for the first time an unequivocal proof of the 

 existence of insect life within the close vessel. Several spinous 

 processes of the acari and other remains were detected floating on 

 the surface of the soluticm, and others attached to the inside of 

 the glass a few lines above the liquid, while, under circumstances 

 somewhat more obscure, several entire dead insects were per- 

 ceived amidst the flakes resting on the bottom of the jar. An 

 omission — of secondary importance, it is true — was now for the 

 first time apparent in the apparatus : this was the want of a fitting 

 shelf or resting-place for the insects ; a circumstance that my 

 kind friend, Andrew Crosse, Esq., when he favoured me with a 

 visit a few weeks after, remarked almost immediately, and said, 

 before he knew that acari had already appeared, " that they 



