calcium chloride in tractor tires

Calcium chloride solution is used to fill tractor tires to make them heavier. Yesterday's Tractors discusses the practice.

the Wardian case

The Wardian case, invented 1829, is the ur-terrarium (and, it surprises me, predates the invention of the aquarium). The Wardian case made it possible for British botanizers to bring in plants from all over the empire, by long sea voyage, alive. It brought ferns to Victorian drawing rooms, and it smuggled tea plants out of China to Assam.

How Ward described his 1829 discovery in his 1852 book On the Growth of Plants in Closely Glazed Cases:

The science of Botany, in consequence of the perusal of the works of the immortal Linnaeus, had been my recreation from my youth up, and the earliest object of my ambition was to possess an old wall covered with ferns and mosses. To obtain this end, I built up some rock-work in the yard at the back of my house, and placed a perforated pipe at the top, from which water trickled on the plants beneath; these consisted of Polypodium vulgare, Lomaria Spicant, Lastroea dilitata, L. Filix mas, Athyrium Filax foemina, Asplenium Trichomanes and a few other ferns, and several mosses procured from the woods in the neighborhood of London, together with primroses, wood-sorrel, &c. In consequence, however, of the volumes of smoke issuing from surrounding manufactories, my plants soon began to decline, and ultimately perished, all my endeavours to keep them alive proving fruitless.
[...]
I had buried the chrysalis of a sphinx [moth] in some moist mould contained in a wide-mouthed glass bottle, covered with a lid. In watching the bottle from day to day, I observed that the moisture which, during the heat of the day arose from the mould, condensed on the surface of the glass, and returned whence it came; thus keeping the earth always in some degree of humidity. About a week prior to the final change of the insect, a seedling fern and a grass made their appearance on the surface of the mould.

I could not but be struck with the circumstance of one of that very tribe of plants which I had for years fruitlessly attempted to cultivate, coming up sponte sua in such a situation, and asked myself seriously what were the conditions necessary for its well-being? To this the reply was -- a moist atmosphere free from soot or other extraneous particles; light; heat; moisture; periods of rest; and change of air. All these my plant had; the circulation of air being obtained by the diffusion law already described.