MISCELLANY. 



505 



tropical America. It has a straight stem, 

 eight or ten feet in height, and produces 

 yellow flowers like those of the sunflower, 

 but smaller. The thick, fleshy, perennial 

 root produces a large number of tubers, in 

 appearance not unlike potatoes. These are 

 not as nourishing as potatoes, but, when 

 properly prepared, are very palatable food, 

 and make a very good soup. It is usually 

 propagated by small tubers or by cuttings, 

 like the potato. 



Tongliencd Glass. A process for in- 

 creasing the cohesive power of glass has 

 been invented by a French engineer, Fran- 

 9ois de la Bastie. This process consists in 

 heating the glass to a certain temperature 

 and plunging it while hot into a heated 

 oleaginous compound. The time occupied 

 in the actual process of tempering is merely 

 nominal, for directly on being heated to the 

 requisite degree, the articles are plunged 

 into the bath and instantly withdrawn. The 

 toughened glass cannot be cut by the dia- 

 mond, and hence when it is used for win- 

 dows it must be cut to the proper size be- 

 fore it is tempered. Articles of this tough- 

 ened glass, such as watch-crystals, plates, 

 dishes, and sheet-glass, were recently exhib- 

 ited in London, and experiments made to 

 show wherein this material differs from com- 

 mon glass. Water was boiled in a saucer 

 over a fire, and the saucer quickly removed 

 to a comparatively cold place ; it was un- 

 affected by the sudden change of tempera- 

 ture. One corner of a piece of glass wa.s 

 held by the hand in a gas-flame until the 

 corner became exceedingly hot, but the heat 

 was not communicated to the other portion 

 of the glass, nor was it cracked from un- 

 equal expansion. 



The following experiment was then made 

 to show how this toughened glass compared 

 with common glass in power of resistance 

 to fracture by the impact of a falling weight. 

 The two pieces of glass to be tested were 

 each about six inches square, and placed in 

 frames, the weight being dropped upon the 

 centre. With the ordinary glass, a two-ounce 

 brass weight, falling on it from a height of 

 twelve and eighteen inches respectively, did 

 no damage, but at twenty-four inches the 

 glass was broken into fragments. With a 

 thinner piece of the toughened glass no im- 



pression was made by the same weight fall- 

 ing from heights ranging from two to ten 

 feet, the weight simply rebounding from the 

 glass. An eight-ounce iron weight, tried at 

 two to four feet respectively, gave similar 

 results. The height being increased to six 

 feet, the glass broke. 



Some of the public prints have ascribed- 

 to Bastie's tempered glass properties which 

 the inventor himself has never claimed for 

 it. Thus it has been qualified as " mallea- 

 able " and " unbreakable." But Mr. Thomas 

 Gaffield, of Boston, a perfectly competent 

 judge, who has examined specimens of this 

 tempered glass, thinks that the true value 

 of this invention is by no means determined 

 as yet. He perceives in it sundry qualities 

 which detract from its usefulness. First, 

 as we have stated, it cannot be cut by the 

 diamond. Then, on being subjected to the 

 sand-blast, it flies into small fragments. 

 Many of the specimens seen by Mr. Gaf- 

 field were not transparent, but only trans- 

 lucent. In ordinary window-glass, if a large 

 pane be broken, the fragments may be cut 

 into smaller panes, but with the De la Bas- 

 tie glass such economy is out of the ques- 

 tion. From the fact that this improved 

 glass, though before the public for a whole 

 year, has not yet found a place in com- 

 merce, Mr. Gafiield is inclined to suspect 

 that the invention is for some reason im- 

 practicable. 



Can Birds converse? Dr. Charles C. 

 Abbott cites the following occurrence to 

 show that birds possess some mode of con'- 

 veying ideas to one another. In the spring 

 of 1872 a pair of cat-birds were noticed 

 carrying materials for a nest to a patch of 

 blackberry-briers hard by. To test their 

 ingenuity, Dr. Abbott took a long, narrow 

 strip of muslin, too long for one bird con- 

 veniently to carry, and placed it on the 

 ground in such a position as to be seen by 

 the birds when searching for material. In 

 a few moments, one of the cat-birds spied 

 the strip and endeavored to carry it off; 

 but its length and weight, however he took 

 hold of it and he tried many times im- 

 peded his flight, and, after long worrying 

 over it, the bird flew off for assistance. In 

 a few moments he returned with his mate, 

 and then, standing rear the strip, they ap- 



