312 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



decided effect in draining the soil, and freeing it from a ma- 

 larious tendency, while it is said to thrive where the animal 

 rain-fall is scarcely sufficient to keep ordinary trees in proper 

 vigor. 



In one case, a specimen raised in Algiers had attained, at 

 the end of eight years, an elevation of nearly thirty-five feet, 

 and a circumference of five feet at a distance of three feet 

 from the ground. In Australia it reaches enormous dimen- 

 sions, equaling, if not exceeding in height, though not in cir- 

 cumference, the far-famed giant trees of California. 



As is well-known, trees having this rapid growth are gen- 

 erally soft and spongy, and of comparatively little value for 

 timber ; but the Eucalyptus is quite the reverse, the wood 

 being very heavy and hard, resisting the action of air and 

 water, as well as of most kinds of insects. In general prop- 

 erties it resembles the wood of the oak, and it is employed 

 very largely for ship -timber in Australia. The growing 

 plants disseminate an aromatic fragrance, which is supposed 

 to be conducive to health. This is due to the volatile essen- 

 tial oil, which can be readily collected, and is known as euca- 

 lyptol. The leaves furnish two and one half per cent, of their 

 weight of this substance, which has come into use already as 

 a solvent of resins, and even of caoutchouc ; and it is warmly 

 recommended for the manufacture of varnish. It is also val- 

 uable as -a febrifuge ; and on this account, in Spain and the 

 south of France, it has been made to replace quinine with 

 decided advantage. Bull. Soc. cV Encouragement ^ etc., Paris, 

 XVII., 342. 



HYDRATED LIME OX WATER-PLANTS. 



Bauer found small crystals on confervoe in a fresh-water 

 pond, which, on farther examination, he discovered to consist 

 of a hydrate of the carbonate of lime, containing five mole- 

 cules of water, precisely similar to those first discovered by 

 Pelouze in a solution of lime in sugar, and subsequently de- 

 tected in a well-tube. This hydrate is distinguished by the 

 peculiarity of losing its water at a temperature higher than 

 59 F., even when under water. 



