US REPORT 1855. 



It would seem, then, as if in these cases the absence or presence of light was 

 almost a matter of indifference. 



In the fourth series of experiments rather a greater variety of species was experi- 

 mented upon, and a larger number of media employed, the total number of seeds in 

 each box being 52, viz. of a species of sunflower, peas, kidney-beans, and barley, 

 10 of each, and of radishes 12, In this instance, the whole number came up under 

 four of the media employed, but these media were of very different qualities ; in one 

 case, all light being excluded; in another, the violet I'ay alone admitted; in another, 

 green light; and in the fourth, a pale green glass being used, which cut off none of the 

 rays completely, although it enfeebled all. 



The number of plumules that were developed in these several instances, were from 

 46 to 47. 



The number of radicles developed under transparent glass was only less by two than 

 the others, so that no fair inference would seem deducible from this series, in favour 

 of one medium being preferable to another. The radicles, however, came up most 

 rapidly in total darkness, and least so when all the rays were admitted. 



Although the above four sets of experiments seemed to render it improbable that 

 any influence, favourable or otherwise, could be ti'aced to particular rays or portions 

 of the spectrum, still it seemed desirable to show more directly, that where the 

 quantity of light was the same its quality was immaterial. 



It was with this view principally that I instituted a fifth set of experiments, in 

 which the light was filtered as it were through liquids — one of which was the ammonio- 

 sulphate of copper, which excluded all but the violet; another, port wine, which 

 admitted only the extreme red ; and a third, a mixture of ink and water, which 

 deadened equally all the rays of the spectrum. 



It was in the first place ascertained, as nearly as could be done by the eye, that an 

 equal amount of light was admitted through each of the media, they being severally 

 diluted with water, until they allowed just so much light to pass as was sufficient for 

 reading the largest print in a chamber otherwise darkened. 



The results appear to show, that there was under these circumstances scarcely any 

 difference to be detected ; nor indeed did a glass, which admitted allthe light present, 

 appear to interfere with the process materially, although in the box from whence light 

 was entirely excluded the germination seemed to go on somewhat less vigorously than 

 in the others. 



It will be seen at least, that out of 50 seeds, or 10 of each of the foflowing, radishes, 

 peas, kidney-beans, sunflower, and barley, 



49 radicles and 48 plumules appeared under port wine. 



49 radicles and 43 plumules appeared under ink and water. 



47 radicles and 36 plumules appeared under transparent glass. 



46 radicles and 48 plumides appeared under \ „^^„„- o,.i„i,„t., ^f „„.,„„,. 

 ,. , 1 ,^o '^i 1 3 J >• ammonio-sulpliate 01 copper. 



45 radicles and 98 plumules appeared under J ^ *^^ 



42 radicles and 37 plumules appeared in total darkness. 



Upon the whole, from a general survey of the above experiments, no other conclu- 

 sion seems deducible, except that light has very little to dodirectly with the germination 

 of seeds ; and that although the popular opinion may be well-founded, namely, that the 

 process goes on best in the dark, as maltsters generally believe, still that the light which 

 interferes with the success of the operation acts chiefly by producing such a degree of 

 dryness as is unfavourable to the sprouting of the seed, and not by itself interfering 

 directly with the result. 



An experienced maltster, indeed, assures me, that darkness is not necessary for 

 malting, although, in order to maintain a suitable degree of humidity in the apart- 

 ment, strong light is generally excluded. 



In the Tables annexed, the numbers attached to each column indicate merely the 

 relative number of radicles or plumules, which had been found to develope themselves 

 under the several media employed, on each of the days of which the date is given. 



