12 



THE AQUARIUM, OCTOBER, 1895. 



leaf surface, would transpire seven and 

 three quarter tons of watery vapor in 

 twelve diurnal hours of clear weather. 

 Carrying the calculations further, a 

 grove consisting of five hundred trees, 

 each with a leaf surface equal to that 

 of the elm mentioned, would return to 

 the atmosphere three thousand eight 

 hundred and seventy-five tons of aque- 

 ous vapor in twelve hours. Indoors, 

 transpiration is during the day only 

 about one-half as active as in the open 

 air, but at night it is about equal in the 

 two situations ; hence the transpiration 

 of a plant indoors is more than one- 

 half as much in twenty-four hours as it 

 would be outside. It follows that grow- 

 ing plants increase the humidity of the 

 atmosphere in closed rooms. This 

 point is very important where the 

 rooms are heated by hot air furnaces. 

 In such rooms the air is drier than in 

 apartments heated by a stove or open 

 fireplace. In a dry atmosphere of the 

 temperature of sixty-five to sixty eight 

 degrees Fahrenheit, a great demand is 

 made upon the system to supply the air 

 with moisture, the skin and rmlmonary 

 mucus membrane are dried, and a con- 

 dition is induced which is expressed in 

 irritability of the nervous system, pale 

 ness and susceptibility of the skin to 

 cold, liability to pulmonary diseases, 

 and, in short, deterioration of all the 

 functions. Now, if the presence of a 

 certain number of thrifty plants in an 

 occupied apartment warmed by dry 

 air, would have the effect of raising the 

 proportion of aqueous vapor, it is clear 

 that plants in rooms heated by hot air 

 furnaces would, in an hygienic point 

 of view, be of very decided value since 

 they may become the means of obviat- 

 ing very distressing symptoms, or even 

 disease itself. As for the question of 

 the relation of forest growth to atmos- 



pheric humidity, and consequently to 

 rainfall, such relation would appear to 

 be clearly established by the author's 

 researches. — Popular Science Monthly. 



TO BLEACH OR WHITEN SKEL- 

 ETON LEAVES, FERNS, 

 MOSSES, ETC. 

 Chloride of Lime, four ounces. Car 

 bonate of Soda, seven ounces. This 

 powder mix with three pints of water, 

 stir it well and let it settle, after which 

 let it filter through filtering paper into 

 a wide mouth bottle or glass jar, add 

 three-fourths water to, or three parts 

 to one jDart of the Alkali into a suitable 

 dish, lay in the stripped or prepared 

 leaves, and keep them in no longer than 

 they whiten, take them out, lay them 

 in clear fresh water, to remove the al- 

 kaline salts, and then lay them in soft 

 paper to absorb the moisture. 



HOUSE CULTURE OF BULBS. 



Roman Hyacinths, Dwarf Tulips and 

 Crocuses are best grown in moss or 

 sand, or in both mixed. 



Any bowl, pot or vase will do for this 



mode of culture. Fill these partly with 

 the moss or sand and on the top of this 

 set the bulbs. Cover them loosely with 



