268 



NA TURE 



\Fcb. I, 1872 



Maclear had erected their instruments. Mr. Davis's pho- 

 too-raphic and Dr. Thomson's polariscopic observations 

 beino- carried on at a little distance below. The instru- 

 menfs represented are the g} reflector constructed by Mr. 

 Browning, with a mounting by Cooke, andthe double 

 refractor, consisting of two telescopes of si.\ inches aper- 

 ture, mounted on one of the universal stands prepared for 

 the Transit of Venus observations in 1874, and lent by the 

 Astronomer Royal. 



The second is a representation of the bungalow 

 which formed the residence of the same party during their 

 stay in India, erected under the friendly shelter of a grove 

 of spreading banyan-trees. The temperature in the middle 

 of the day at Canara reaching commonly to 90° Fahr. 

 within doors, it will be seen how necessary was not 

 only the shelter of the trees for their residence, but 

 the umbrella which a native attendant is holding over the 

 head of one of the observers during the actual time of 

 observation. 



ON THE INFLUENCE OF VIOLET LIGHT ON 

 THE GROWTH OF VINES, AND ON THE 

 DEVELOPMENT OF PIGS AND BULLS 



GENERAL A. J. PLEASONTON, from Philadelphia, 

 U.S., has been engaged since i86i with some very 

 interesting experiments on the influence of light, trans- 

 mitted through violet glass, in developing animal and 

 vegetable life. In April iiS6i, cuttings of vines of some 

 twenty varieties of grapes, each one yearold, of the thick- 

 ness of a pipe-stem, and cut close to the spots containing 

 them, were planted in the borders inside and outside of 

 the grapery, on the roof of which every eighth row of 

 glass was violet-coloured, alternating the rows on the op- 

 posite sides. Very soon the vines began to attract great 

 notice from the rapid growth they were making. Every 

 day the gardener was kept busy in tying up the new wood 

 which the day before had not been observed. In a few 

 weeks after the vines had been planted, the walls and 

 inside of the roof were closely covered with the most 

 hixurious and healthy development of foliage and wood. 



In September of the same year Mr. Robert Buist, a 

 noted seedsman and horticulturist, from whom the General 

 had procured the vines, visited the grapery. After 

 examining it very carefully, he said ; — " I have been cul- 

 tivating plants and vines of various kinds for the last forty 

 years ; I have seen some of the best vineries and con- 

 ser\atories in England and Scotland ; but I have never 

 seen anything like this growth." He then measured some 

 of the vines, and found them forty-five feet in length, and 

 an inch in diameter at the distance of one foot above the 

 ground. And these dimensions were the growth of only 

 five months ! 



In March 1862 they were started to grow, having 

 been pruned and cleaned in January of that year. The 

 growth in this second season was, if anything, more 

 remarkable than it had been in the previous year. Besides 

 the formation of the new wood, and the display of the 

 most luxuriant foliage, there was a wonderful number of 

 bunches of grapes, which soon assumed the most remark- 

 able proportions— the bunches being of extraordinary 

 magnitude, and the grapes of unusual size and develop- 

 ment. 



In September, when the grapes were beginning to colour 

 and to ripen rapidly, Mr. Buist visited ttie grapery again, 

 and estimated that there were 1,200 pounds of grapes. 

 General Pleasonton remarks that in grape-growing coun- 

 tries, where grapes have been grown for centuries, a period 

 of time of from five to six years will elapse before a single 

 bunch of grapes can be produced from a young vine ; 

 while here, only seventeen months after, his grapery had 

 yielded the finest and choicest varieties of grapes. 



During the next season (i)'63) the vines again fruited, 

 and matured a crop of grapes, estimated, by comparison 



with the yield of the previous year, to weigh about two 

 tons ; the vines were perfectly healthy, and free from the 

 usual maladies which affect the grape. Many cultivators 

 said that such excessive crops would exhaust the vines, 

 and that the following year there would be no fruit ; as it 

 was well known that all plants required rest after yielding 

 large crops. Notwithstanding, new wood was formed this 

 year for the next year's crop, which turned out to be quite 

 as large as it had been in the season of 1863 ; and so on, 

 year by year, the vines have continued to bear large crops 

 of fine fruit without intermission for the last nine years. 

 They are v-ovi healthy and strong, and as yet show no 

 signs of decrepitude or exhaustion. 



The success of the grapery induced General Pleasonton 

 to make an experiment with animal life. In the autumn 

 of 1 869 he built a piggery, and introduced into the roof 

 and three sides of it violet-coloured and white glass in 

 equal proportions — half of each kind. Separating a recent 

 litter of Chester country pigs into two parties, he placed 

 three sows and one barrow pig in the white pen, and 

 three other sows and one other barrow pig in the pen 

 under the violet glass. The pigs were all about two 

 months old. It will be observed that each of the pigs 

 under the violet glass was lighter in weight than the 

 lightest pig of those under the sun-light alone in the 

 white pen. The two sets were treated exactly alike; 

 fed with the same kinds of food, at equal intervals of 

 time, and with equal quantities by measure at each 

 meal, and were attended by the same man. On the 4th 

 of May, 1870, the six sows, being weighed, the following 

 conclusion was obtained : - 



November 3, iS 

 March 4, 1870 



r the violet pen 

 .. 122 lbs. 

 ... 520 lbs. 



Under the white pen?. 



144 lbs. 

 ... 530 lbs. 



Increase 39S lbs. ... 386 lbs. 



Consequently, akhough the pigs placed under the violet 

 pens actually weighed 10 lbs. less than those under the 

 white pens ; yet, taking into consideration the 22 lbs. 

 less which the first pigs had previously weighed, there is 

 an actual gain of 1 2 lbs. The two other barrow pigs 

 oftcred nearly the same result. 



The next experiment of General Pleasonton was with 

 an Alderney bull calf, born on Jan. 26, 1870. At its 

 birth it was so puny and feeble that the man who attends 

 upon his stock — a very experienced hand — told him that 

 it would not live. He directed him to put it in one of 

 the pens under the violet glass. In 24 hours a very 

 sensible change had occurred in the animal. _ It had 

 arisen on its feet, walked about the pen, took its food 

 freely by the finger, and manifested great vivacity. In a 

 few days his feeble condition had entirely disappeared. 

 It began to grow, and its development was marvellous. 

 On March 31, 1S70, two months and five days after its 

 birth, its rapid growth was so apparent that, as its hind 

 quarter was then growing, he had it tneasured. Fifty 

 days afterwards it had gained six inches in height, carry- 

 ing its lateral development with it. The calf was turned 

 into the barn yard, and manifested every symptom of full 

 tiiasculine vigour, though at the time he was only four 

 monihs old. He is now one cf the best developed animals 

 that can be found anywhere. 



This is only a very short rcsimic of the third edition of 

 a painphlet published by General Pleasonton, entitled, 

 " On the Influence of the Blue Colour of the Sky in De- 

 veloping Animal and Vegetable Life : as Illustrated in 

 the Experiments of the Author between the years 1 861 

 and 1S71" (Philadelphia, 1S71). 8vo. 24 pp. 



The account of it which I had addressed to the French 

 Academy was followed by two different notes from 

 Cailletet and Bert. In my next article I will examine 

 them, with sonre references to the explanation of General 

 Pleasonton's experiments. 



Paris, Jan. 10 Andr£ PoiJY 



