THE FARMER'S MAGAZINE. 



273 



plays of the Divine wisdom and beneficence, and 

 so closely allied in its aesthetical aspect with every 

 interest, social and domestic, might have been ex- 

 pected to form a part in our educational courses, 

 or, through the agencies of cheap literature and 

 popular exposition, to have commanded a place in 

 the school and in the drawing-room, and to have 

 gilded, if not to have replaced, the frivolities of 

 fashionable life. Such expectations, however, have 

 not been realized. Men of science who are much in 

 the society of the educated world, and especially of 

 those favoured classes who have the finest oppor- 

 tunities of acquiring knowledge, are struck with 

 the depth of ignorance which they encounter ; 

 while they are surprised at the taste which so gene- 

 rally prevails for natural history pursuits, and at 

 the passion which is universally exhibited even for 

 higher scientific information wliich can be com- 

 prehended by the judgment and appropriated by 

 the memory. The prevailing ignorance, therefore, 

 of which we speak, is the offspring of an imperfect 

 system of education, which has already given 

 birth to great social evils — to financial laws unjust 

 to individuals, and ruinous to the physical and 

 moral health of the community. If the public be 

 ignorant of science, and its applications, in their 

 more fascinating and intelligible phases ; if our 

 clergy, in their weekly homilies, never throw a 

 sunbeam of secular truth among their people ; if 

 legislators hardly surpass their constituents in 

 these essential branches of knowledge, how can the 

 great interests of civilization be maintained and ad- 

 vanced ? how are scientific men to gain their place 

 in the social scale ? and how are the material in- 

 terests of a great nation, depending so essentially 

 on the encouragement of art and science, to be pro- 

 tected and extended ? How is England to fare, if 

 she shall continue the only civilized nation which, 

 amid the perpetual struggles of political faction, 

 never devotes an hour of its legislative life to the 

 consideration of its educational establishments and 

 the consolidation of its scientific institutions? 



Impressed with the importance of these facts, 

 and in the hope that some remedy may be found 

 for such a state of things, we have drawn uj) the 

 following article, in order to show how much use- 

 ful and popular and pleasing information may be 

 learned from a popular exposition of the nature 

 and properties of the single element of light, in its 

 sanitary, its scientific, and its artistic or ccsthetical 

 relations. Should our more intelligent readers 

 rise from its perusal with information which they 

 had not anticipated, and which they had previously 

 regarded as beyond their depth, our labour in pre- 

 paring it will be amply rewarded, and we shall 

 hope to meet them again in other surveys of the 

 more popular branches of science. 



I. In attempting to expound the influence of 

 light as a sanitarij ayent, we enter upon a subject 

 which, in so far as we know, is entirely new, and 

 upon which little information is to be obtained; 

 but, admitting the existence of the influence itself, 

 as partially established by observation and analogy, 

 and admitting too the vast importance of the sub- 

 ject in its personal and social aspects, we venture 

 to say that science furnishes us with principles and 

 methods by which the blessings of light may be 



diffused in localities where a cheering sunbeam has 

 never reached, and where all the poisons and 

 malaria of darkness have been undermining the 

 soundest constitutions, and carrying thousands of 

 our race prematurely to the grave. 



The influence of light upon vegetable life has 

 been long and successfully studied by the botanist 

 and the chemist. The researches of Priestley, 

 Ingenhousz, Sennebier, and De CandoUe, and the 

 more recent ones of Carradori, Payen, and Macaire, 

 have placed it beyond a doubt that the rays of the 

 sun exert the most marked influence on the respira- 

 tion, the absorption, and the exhalation of plants, 

 and, consequently, on their general and local nutri- 

 tion. Dr. Priestley tells us, " It is well known that 

 without lujht no plant can thrive ; and if it do grow 

 at all in the dark, it is always white, and is in all 

 other respects in a sick and weakly state." He is of 

 opinion that healthy plants are in a state similar to 

 sleep, in the absence of light, and that they resume 

 their proper functions when placed under the in- 

 fluence of light and the direct action of the solar 

 rays. 



In the year 1835, D. Daubeny communicated to 

 the Royal Society a series of interesting experi- 

 ments on the action of light upon plants, when the 

 luminous, calorific, or chemical rays were made 

 preponderant by transmission through the follow- 

 ing coloured glasses or fluids : — 



The general result of these experiments is thus 

 given by their author ; " Upon the whole, then, I 

 am inclined to infer, from the general tenor of the 

 experiments I have hitherto made, that both the 

 exhalation and the absorption of moisture by 

 plants, so far as they depend upon the influence of 

 light, are affected in the greatest degree by the 

 most luminous rays, and that all the functions of 

 the vegetable economy which are owing to the pre- 

 sence of this agent, follow, in that respect, the same 

 law." 



This curious subject has been recently studied in 

 a more general aspect by Mr. Robert Hunt, who has 

 pubhshed his results in the Reports of the British 

 Association of 1S47. Not content with ascertain- 

 ing, as his predecessors had done, the action of the 

 sun's white and undecomposed light upon the ger- 

 mination and growth of plants, he availed himself 

 of the discovery of the chemical or invisible rays 

 of light, and sought to determine the peculiar in- 

 fluence of these rays and of the various coloui s of 

 solar light upon the germination of seeds, the growth 

 of the wood, and the other functions of plants. 



In order to explain the results which he obtained, 

 we must initiate the reader into the constitution of 

 the white light which issues from the sun. If we 

 admit a cyhndrical beam of the sun's light through 

 a small circular aperture into a dark room, it will 



