August 20, 1S72. ] 



JOURNAL OF HORTICULTURE AND COTTAGE GARDENER. 



171 



under similar circumstances only three grains, and as he re- 

 marked this power of soils to absorb moisture from air is much 

 connected with their fertility, when this power is great the 

 plant is supplied with moisture in dry seasons, and the effect 

 of evaporation in the day is counteracted by the absorption 

 of aqueous vapour from the atmosphere by the interior parts 

 of the soil during the day, and by both the exterior and in- 

 terior during the night (Agric. Chem., 181.) And then with 

 regard to the leaves of plants, it is worthy of more extended 

 remark that leaves appear to act in somewhat different ways 

 in receiving and depositing dew. A blade of grass is some- 

 times spangled over with dew drops, but it usually becomes 

 wetted throughout its whole surface by the drops running to- 

 gether, and thus the water is conducted to the earth in minute 

 streamlets ; whereas the leaves of the Clover, Cabbage, Nas- 

 turtium, and many other plants will be found to collect dew in 

 distinct globules, which may be rolled about on the leaf with- 

 out appearing to moisten its surface. These drops, in fact, do 

 not touch the leaf, but rest and roll upon a pillow of air inter- 

 posed between them and the substance of the leaf. 



The same remarks apply to plants growing in far warmer 

 climates than our own ; thus the repulsion of water by the 

 leaves of certain plants, and by the feathers of water fowl, has 

 been investigated by Dr. C. Buist [Proc. Roy. Soc, 1857, p. 520). 

 In some experiments carried on at Bombay with four varieties 

 of Lilies and the Lotus, he found that from the upper surface 

 of the Lily leaf the water runs off without wetting it, at it does 

 off a piece of glass or greased surface. From the Lotus leaves 

 it flows off like a pool of quicksilver, reflecting light from the 

 whole of its lower surface. The repellent power is on the 

 upper side of the leaf only. " On examining," remarks Dr. 

 Buist, " into the cause of this, I found the Lotus leaf covered 

 with short microscopic papilla 3 , which entangle the air and 

 establish an air-plate over the whole surface, with which in 

 reality the water never comes in contact. Another peculiarity 

 connected with this was the singular respiratory pores of the 

 Lotus. The leaves of the Lotus, when full-sized, are from a 

 foot to 16 inches in diameter ; on cutting off a leaf 6 inches 

 broad, the stalk of which was less than the third of an inch in 

 diameter, I was able to collect 33 cubic inches of air in an 

 hour, when the vital energies of the plant must have been in- 

 jured by its mutilation. At this rate a tank covered with 

 Lotus leaves would produce daily an atmosphere 4 feet in 

 depth throughout its whole surface. "When the leaf is pushed 

 slightly under water, a constant succession of air-bubbles seem 

 to arise from it, at the rate of two or three a-minute at each 

 spiracle. The air-bubble diffuses itself as it is extricated, pre- 

 senting a very broad base to the leaf, and seems detached with 

 difficulty. The air-plate all over the surface must thus be- 

 come continually renewed, and the arrangement kept perfect. 

 Sensible respiration is not at all essential to the repelling 

 power of leaves ; the most beautiful manifestation of it I have 

 met with is in the Pestia, a little floating water plant abound- 

 ing in our shallow tanks, and resembling common Endive. 

 When pushed under the surface it looks like a little mass of 

 burning silver. The same appearance is presented on Cabbages, 

 young Clover, and a vast variety of other leaves; it is the 

 cause of the bright pearl lustre of dew. 



■ We are all aware that dew is derived from the condensation 

 of the insensible vapour always present in the state of steam 

 in our atmosphere, and that this is deposited on such plants or 

 soils as are colder than that steam. This colder temperature, 

 called the dew point varies, in different seasons. In the western 

 side of our island the temperature of the dew point averages 

 about 40° in January and February, gradually rises to about 

 58° in July and August, and descends to about 43° in December. 



The varying amount of the aqueous vapour- in the atmo- 

 sphere is very noticeable. Around London a cubic foot of air 

 contains on an average in January only 2.2 grains ; 2.9 grains 

 in March ; and then it gradually increases to 4.8 grains in July. 

 The amount then slowly decreases to 3.1 grains in December. 

 This larger presence of moisture in our atmosphere during the 

 warmest season of the year will hardly escape the reader's 

 notice, or fail to excite his gratitude to our Heavenly Father 

 who has thus arranged that when our plants are in summer 

 most needing a supply of moisture, that then it is found in the 

 greatest quantity in the air around them, and thus, when in 

 the driest seasons other sources of supply are absent, this is 

 the most copious. 



until I used gas lime from the gasworks. I applied it thinly 

 with a shovel. It kills everything with which it comes in con- 

 tact. I have not been troubled with those weeds for nearly 

 three years. I prefer gas lime to salt ; the smell of it is not 

 pleasant at first, but it soon passes away. — A Gardenee, 



Killing Weeds on Walks.— Sedum acre (Stoneerop), Grasses, 

 and the like on carriage roads and walks I was troubled with 



SEARCH FOR THE VICTORIA REGIA. 



Obidos, January 16th. — Since my arrival ou the Amazon I 

 have inquired in each place and on board of all the steamers, 

 of every one I met, where the Victoria Regia could be found. 

 But the answers I received were anything but satisfactory. 

 Everybody said there were great quantities of them. Some 

 said it was not the season, and no one could say with any 

 certainty where they were to be found ; only the day before yes- 

 terday, talking with an old Englishman who had spent forty 

 three years on the river, I ascertained that in some lakes near 

 here the plant had been seen, and I resolved to find it or get 

 my feet wet in the attempt. So, after much preliminary con- 

 versation, I embarked yesterday morning at 10 a.m.; in a mon- 

 taria, in company with the Lieutenant of Police and the Notary 

 Public of this town, two Indians to paddle, sardines, bread, 

 cheese, and wine for the inner man, my Spencer rifle for un- 

 known Amazonian monsters, and myself as chief of the party, 

 and started on my search for the Victoria Regia, a fine speci- 

 men of which now stands before me in an immense china vase. 

 I mention this fact at once, that you may not remain in any 

 cruel suspense as to the result of our expedition. 



The day was fine, and the clouds dense (cloudy days are 

 considered fine on the Amazon) ; and our Indians sent our 

 canoe swiftly along under the banks of the great river, stopping 

 only once every five minutes to make an immense cigar out of 

 native tobacco and tascui (the inner bark of a tree), which 

 they gravely smoked while they paddled our light canoe. 



The heat was intense, the air stagnant; clothes seemed 

 insufferable, and my rifle increased in weight with every step ; 

 and still an Indian boy, our guide, pushed on, turning and 

 avoiding the impassable parts as though every inch of the 

 primeval forest was familiar to him. 



Once we had to pass a muddy creek, over which extended 

 the half-burnt trunk of a mammoth tree ; the boy leaped 

 lightly over, clinging to the trunk with his bare feet like a 

 bird. I paused, looked around, across, below, where I saw the 

 heads and vile little eyes of three alligators gazing hungrily at 

 me out of mud and water in which they were lying, took my 

 rifle in both hands like a balance pole, and pushed over, ex- 

 pecting every step that my muddy boots would slip, and I 

 should be precipitated into the slime below. I should think 

 we had gone on this way for a mile and a half when the boy 

 said, " There they are!" and, looking ahead, I saw a large 

 open space in the forest, covered with high grass. More 

 eagerly I pushed on, gained the open, forced my way through 

 the high grass to the shore of a small pond, and — Eureka ! — 

 the Victoria Regia lay before me. - 



In spite of heat, dirt, and fatigue, I did feel enthusiastic, and 

 gave utterance to some exclamations, which, as nobody present 

 understood, have not been correctly reported, and I spare you 

 the infliction. What I did do, however, was to give the boy a 

 knife, in ease of alligators, and send him at once into the pond 

 to cut with care a leaf, and bring it ashore, and then a bud. 

 Flowers there were none open. 



I will not attempt to describe it. 'Twould be in vain, and 

 it has already been done ; but, in examining the under side of 

 the leaf, I saw at a glance how Paxton took his idea of the 

 Crystal Palace from the structure of this leaf. After admiring 

 sufficiently while the boy scraped the thorns from the stem of 

 the bud (for both flower and leaf are abundantly provided with 

 sharp thorns resembling the Thistle) , I took my prize ; and 

 we retraced our steps, found our canoe, woke up our Indians, 

 and paddled down stream towards home, which I reached 

 about 5 p.m. hot, sunburnt, weary, my clothes soaked with 

 perspiration, and hungry as a bear. I gave my bud to one of 

 the gills, who put it in water, and after a refreshing bath sat 

 down to dinner ; and, while enjoying it, I heard a report 

 behind me (where the hud was) like that of a gun — I mean a 

 very small Potato pop-gun — and, lo ! the bud had burst and 

 was rapidly opening. In the course of half an hour it was a 

 perfect flower of a pure white like our pond Lily, with the 

 centre leaves of a rose colour gradually growing deeper till the 

 centre was of a brilliant carmine ; and, contrary to expecta- 

 tions, it had a most delicious fragrance, as nearly resembling 

 that of a ripe Pine Apple as anything I can compare it to. 



