248 



I'HE GARDENER'S MONTHLY 



\_Auguiit, 



edge is, for the mo.sl part, obtained in iliiMets, 

 and is the reward usually of inquirinjj; spirits 

 that enter upon the apreeable task of interroga- 

 ting nature, Imving detinite ends in view. It is 

 not for us, therefore, to speak slightingly of the 

 many experiments that have been made on the 

 effects of variously-colored light on the growth 

 of plants. It is proper, however, to ask what is 

 the sum-total of results? What remains to be 

 discovered none can predict; but of what has 

 been done the sum is amusingly small, and one 

 general restilt is peculiarly interesting. The 

 • general result is that the common daylight suits 

 plants better than any modification of it that we 

 can obtain by chemical or optical agencies. If 

 the philosophers could have discovered a better 

 sort of light they would frankly have told us; 

 but thus far, at all events, it appears that the 

 arrangements of nature are not susceptible of 

 improvement by the aid of art. Any one who 

 will take the pains to collect and read the many 

 elaborate essays on the subject tnat have been 

 published, will at least earn a surprise in the re- 

 flection that will come at last on the immense 

 pains taken by man to satisfj'' his mind that the 

 Almighty has not made a mistake in adapting 

 the imponderable forces of the universe to the 

 necessities of the organisms with which the 

 planet is beautified. From this general result 

 we turn to a particular result, which we may 

 speak of ixa having a " practical " value. It is 

 quite certain that many plants thrive more thor- 

 oughly when exposed to light in which there is 

 a distinct preponderance of green color, than in 

 the full blaze of common daylight. The fern 

 houses at Kew are all roofed with green glass, 

 and in many instances it has been found that a 

 thin coat of green paini, or of less permanent 

 green coloring, on the roof of an ordinary plant 

 house, affords a more salutary shade than the 

 grey canvas or stippling of lime customarily em- 

 ployed. The green light thus produced does not 

 suit all plants alike, for this particular conclu- 

 sion is but a part of the general conclusion, that 

 the arrangements of nature cannot be improved 

 upon by art. The fact is, in the use of green 

 glass we are in some degree — perhaps in a very 

 feeble degree — imitating the light received by 

 plants that commonly grow under the shade of 

 trees. Hitherto we have seen the best results of 

 the employment of green glass in the cultiva- 

 tion of Ferns and Camellias; but it cannot be 

 doubted that very many families of plants would 

 enjoy a tint of green similar to that produced by 



the passage of white light through a screen of 

 grocn leaves. We have prol)ably much to learn 

 in adapting the circumstances of plants under 

 cultivation to the kind of light that prevails in 

 their native habitats." 



The American gardener knows well that there 

 are large numbers of plants that " common day- 

 light " does not suit. The argument that "the 

 Almighty knows what is best for us," is all very 

 well. He knows what is best for his own good 

 and wise purposes, but we have a suspicion that 

 he leaves a good deal of what is best for us to 

 be found out by the industrious human brain. 

 It would have been just as good for our great- 

 grandfathers as for us to have found out how to 

 cross the great ocean in ten days, as we do. And 

 they could have found out, if any of them had 

 had the sense to study little things, as Watt and 

 Fulton did. Any one who knows the difference 

 between a wild Crab and a Baldwin, will doubt 

 whether nature alwaj's knows just what is best 

 for us. 



It is just so with blue glass. We feel sure it is 

 not all that is claimed for it. On the other hand, 

 we are sure that there may be much more made 

 of blue glass in our horticultural operations than 

 has been made. — Ed. G. M. 



Internal Heat of Plants. — By accounts in 

 the English papers, we note that an observer 

 has been experimenting with leaves and stems, 

 to ascertain the diflerence, in their temperatures 

 at different times of the day, as compared with 

 that of the atmosphere. He found they were 

 about two degrees lower before noon, but several 

 higher from that till night. He seems to have con- 

 fined his observations to beet leaves and sun flow- 

 ers. We should like to see other plants tried, 

 especiallj' the ice plants. They take their name 

 from the ice-like crystals on the leaves; but, 

 whether it is imagination or not, we cannot say, 

 there is always a cold feel to the leaves as well. 



The American Association. — The meeting 

 this year is to be held at Nashville, on the 29th 

 of August. It is expected to be a very interest- 

 ing one. 



Double Flowers. — Almost, perhaps all the 

 double forms of herbaceous flowers have been 

 found wild, and taken to our gardens. Collect- 

 ors frequently find them, and more could if they 

 would look shai-p. In an earl}^ number of the 

 American Naturalist, Mr. Thomas Meehan record- 

 ed the finding of Saxifraga Virginiensis with 

 double flovvers on the Wissahickon, and Dr. Asa 



