PROFESSIONAL AND MORAL TRAINING. 
sixth of an inch in the expansion of the fore-wings, which, as well as the body, are of a greenish 
golden colour, with a purple gloss at the extremity, and the head is red, or hrick red, and very woolly. 
Its larva? are small orange-coloured grubs, destitute of legs, which reside within the substance of the 
leaves, forming very tortuous tracks, gradually increasing in width, with a slender black line down 
the middle, formed of the excrement of the caterpillar. When full grown they quit the leaf, piercing 
a hole through one of its dried surfaces, and contrive to crawl down the stem of the leaf till they 
reach some place of safety, where they form their cocoons, and where the moths are subsequently 
developed. Fig. 4,/ represents a rose leaf with three of the burrows of the larvse. 
PROFESSIONAL AND MOEAL TEAINING. 
HINTS ADDRESSED TO YOUNG GARDENERS. 
By Me, W. P. KEASE, Author or the " Beauties of Surrey" and of " Middlesex." 
MEAT applied to a seed is the cause of its immediate germination and growth ; and to every tree, 
plant, and vegetable is the cause of the rising of its sap, the budding and unfolding of its leaves 
and blossoms, and the ripening of its fruit and seed. What is true of one seed or tree is true of the 
whole of the vegetable creation. If we inquire what it is that animates and beautifies all nature, the 
answer will be, heat. It is by it that nature is made to assume the various changes so productive of 
useful results. The influences of the changes of seasons, and of the position of the sun on the pheno- 
mena of vegetation, plainly demonstrate the effects of heat on the functions of plants, The activity of 
chemical changes in plants is increased by a certain increase of temperature, and even the rapidity of 
the ascent of fluids by capillary attraction. The fermentation and decomposition of animal and 
vegetable substances are produced by a certain degree of heat, which is consequently necessary for the 
preparation of the food of plants, and as evaporation is increased as the temperature is raised, the 
superfluous parts of the sap are most readily carried off at the time its ascent is quickest. 
Next to the solar beams, as an agent in the support of vegetable life in all its various forms, is 
water, which operates as a medium in conveying and imparting to the solid substances of organisation, 
the influence of the imponderable agents, as heat, light, and electricity, as well as that of the vital 
energy itself. 
As the state of moisture depends primarily on the pressure of a gaseous vapour, its quantity and 
its tension or elasticity is of course finally dependent on temperature, and on the agency of solar 
radiation. Certain plants are peculiar, as is well known, to the tropical regions where a high degree 
of heat prevails, with its necessary attendant, a very humid atmosphere, — whence the richness and 
luxuriance of organic existence in these climes. Ascending in the torrid zone from the level of the 
sea to the summits of the mountains, we pass through all the various climates, with their respective 
gradations of organised matter which each hemisphere of the entire globe presents as we proceed from 
the equator to the pole. This is abundantly exemplified in the floras of Nepal and Mexico. 
It is sufficient for the precipitation of moisture that two portions of air of different temperatures, 
but each containing the full complement of vapour due to its temperature, be mixed together. The 
temperature speedily arrives at the mean, but the mean temperature cannot support the mean quantity 
of vapour, a portion of it is therefore precipitated in the form of cloud, rain, or snow, according to 
circumstances. Hail is produced by the falling of rain from a warmer through a colder stratum of 
air. Dew is formed only on the surface of the earth, and arises by the cooling of bodies by radiation ; 
hence it occurs on the coldest portions of the best radiators, such as grass, and only on clear nights 
when the temperature can then fall considerably. It is most abundant in tropical countries, where 
the quantity of vapour in the air is greatest, and in our climate most dew occurs iu autumn and 
spring, there being at these seasons the greatest difference between the temperature of day and 
night. 
The atmosphere consists of oxygen and nitrogen gases, with a very small proportion of carbonic 
acid gas. In one hundred volumes of pure atmospheric air, there are eighty volumes of nitrogen, and 
twenty volumes of oxygen, and although the portion of carbonic acid is small (one part in 2500 parts 
of atmospheric ah-), it performs a very important part in the nutrition of plants. The leaves and green 
parts of trees, plants, and vegetables inhale it in combination with the oxygen ; " but to catch this very 
minute quantity, the tree hangs out thousands of square feet of leaf in perpetual motion, and thus by 
the conjoined labour of millions of pores, the substance of whole forests of solid wood is slowly 
extracted from the fleeting winds." 
The decay of vegetable matter in the soil proceeds only when there is an access of air and water. 
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fff^73 S ^^ Il 
