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ON VARIEGATION IN PLANTS. 
jar, simply covered with a flat slate , and yet retain causticity sufficient to destroy the mosses and 
lichens which infest the stems of currant and gooseherry bushes. 
Hot lime also meliorates rich alluvial clays replete with vegetable organic matter. 
Hydrate of lime, or, to use the more familiar term, slaked lime, is quickly prepared, as every one 
knows, by sprinkling hot lime with water. The lime heats, (that is, absorbs, and fixes, and solidifies 
water, — thus liberating the matter of heat which gave it fluidity), swells, cracks, and falls into powder. 
Again, by simple exposure to the ah', hot lime becomes gradually slaked, attracting and combining with 
atmospheric moisture : it is then called air-slaked lime, and, though a small portion of floating carbonic 
acid may have combined and so far carbonated the lime, it still retains its causticity. Fresh lime 
requires about one third of its weight of water to convert it to dry powdery hydrate. 
Lime water prepared with cold water, — if at the freezing, or thirty-second degree of Fahrenheit, — 
contains from eleven to thirteen grains by weight in the pint (Imperial) : its taste is acrid ; by it the 
tint of vegetable blues is converted to green ; but it cannot retain its alkaline causticity unless it be 
kept in closely stopped bottles. The solubility of lime in ice-cold water, and the almost total insolu- 
bility of chalk in water at any degree of temperature, furnish the ready means of rendering hard waters 
comparatively soft ; as was proved by Professor Clark of Aberdeen, when he described the processes by 
which the waters supplied to London might be deprived of the bicarbonate of lime, which renders them 
so hard as to be not only insalubrious, but wholly unfit for the laundry. Gardeners would do well to 
investigate and apply that simple process, by which a vast saving of soap, soda, and labour, would be 
made at the small cost of a minute quantity of fresh hydrate of lime, added to many hundred gallons 
of very hard water. 
The direct application of lime to ground and plants infested by soft molluscs — shelless slugs, and 
snails, is familiarly known ; but not so much as it ought to be : and another fact is, that two applications, 
one about nine or ten p.m., and the other before sunrise, are required to effectually destroy the vermin: 
to be repeated several times at short intervals. Both lime and salt act by that affinity for water which 
each exerts upon moist surfaces : slaked lime is a safe application, but salt would destroy growing 
vegetables — and none sooner or more fatally than the box edgings of gardens. 
I have so far dwelt only upon the minor uses of hot and mild lime. One of the greatest moment, 
however, was announced some years ago, when Professor Rowlandson proved that hmnic acid, inert 
peat bogs, and earth glutted with black dung, were attracted and fixed by lime ; and in the form of 
slowly soluble humate of lime, converted to a salubrious element of vegetable nutrition. I worked out 
that writer's facts, and established their veracity. But lime claims pre-eminence in a degree and form 
that were entirely unsuspected, till revealed by Messrs. Thompson and Way's numerous experiments. 
Some lime must be present in soils to give them the power to absorb and^ manures. (See vol. ii. 218). 
ON VAEIEGATION IN PLANTS* 
By Dr. MORRErT, Professor in the University of Liege. 
CLASSIFICATION WITH EXAMPLES AMONG HAHDY PLANTS. 
¥E cannot enumerate all the species which indicate variegation ; but we have been led, by the dif- 
ferent modes or forms in which the variegation is developed, to classify certain of them according 
to a method which is at once physiological and phytographical. This method is physiological in the 
sense that it permits us to seize upon all the variations according to which the phenomenon takes 
place, in showing the relations of the coloured parts with the margins, with the summit, the base, the 
nerves, and the intervening spaces of the blade of the leaf ; it is phytographic in so far as that it 
establishes a fixed and simple nomenclature, which enables us to express without figure and with 
precision the exact manner according to which the anormal tint is distributed. The first point of 
view permits us to conceive the influences exercised, without doubt, by the different organs of the leaf 
on one another to induce the variegation ; and the second enables us to determine the possible com- 
binations among the colours and the variegated parts in a given species. 
It is proper to remark that variegation is a different phenomenon from spotting : the one is normal, 
natural, constant in one species, and characteristic ; the other is anormal, exceptional, variable, un- 
healthy, and expressive of an individual state. Anatomically considered, spotting is further different 
from variegation ; the one has its seat in the diachyma, the other in the skin ; the one is profound, the 
other superficial. 
From Dodonwa, on Rccueil d' Observations dc Botaniquc. Brussels. 
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