POPULAR MISCELLANY. 



33 



Why Wool felts. The cause of the felt- 

 ing properties of wool is generally attrib- 

 uted to serratures on the surface of the 

 fibers, which are supposed, when driven into 

 the closest possible contact, to hook into one 

 another, and so to hold together by what 

 might be called a " beggar's-lice grapple." 

 The validity of this theory was called into 

 question by two gentlemen of Hartford 

 Captain George R. Case, a microscopist, and 

 Mr. Joseph Dawson, a woolen manufacturer. 

 These gentlemen, obtaining samples of wool 

 of different grades, subjected them to vari- 

 ous manipulations, and found: 1. That a 

 single fiber of wool, when manipulated by 

 itself in a lubricant of soap, has no fulling 

 property, but rather a tendency to lengthen 

 the fiber ; 2. That a number of fibers placed 

 side by side, just as they grew on the sheep, 

 and with simply tension enough to take out 

 the kinks, when manipulated with a lubri- 

 cant of soap, have no felting property, 3. 

 That fibers similarly treated, but with the 

 roots and tips alternating, have no fulling 

 or felting property, and no power of adhe- 

 sion ; but, 4. That a number of fibers placed 

 side by side, with the tips all one way or 

 with the roots and tips alternating, without 

 any tension, have fulling properties ; and, 

 5. That fine-carded wool, taken from a sec- 

 ond breaker, with the fibers thoroughly 

 mixed, has great fulling properties when 

 properly manipulated. A sample of negro's 

 hair of suitable length, which was found 

 by microscopical examination comparatively 

 free from serratures but slightly spiral in 

 structure, manipulated in the same manner 

 as the wool had been, was formed into a 

 " well-felted sample of cloth." These and 

 other experiments satisfied the authors that 

 the fulling properties of wool or any other 

 fibers were in proportion to the number of 

 waves, curls, or kinks, and their degree of 

 fineness, and that the serratures, per se, have 

 little to do with the matter, excepting pos- 

 sibly that which may be due to friction. 

 " To the question, What is the cause of the 

 fulling or felting of wool ? the simplest an- 

 swer possible is, it is the looping and in- 

 terlooping, locking and interlocking of the 

 fibers until they become inextricably en- 

 tangled, but by interlooping and interlock- 

 ing, and not upon the beggar's-lice prin- 

 ciple." 



Spade-Foot Toads Dr. Charles C. Ab- 

 bott contributes to the " American Natural- 

 ist " a study of the hermit spade-foot toad 

 {Scaphiophis Holbrooki), a rare animal, whose 

 custom it seems to be to appear unexpect- 

 edly in numbers, and, after a few days, sud- 

 denly to disappear. Its name is derived 

 from its long, horny index-toe, which may 

 well be characterized as a spade, for it digs 

 with it rapidly into the ground ; and its 

 voice, immense for so small an animal, is 

 like a steam-whistle. The spade-foots first 

 visited Dr. Abbott's field of observation in 

 May, 1874, 6tayed a few days, and were 

 gone. Their next visit, ten years having 

 passed without a single specimen being seen 

 or heard, was April 10, 1884, in the same 

 spot, a sink-hole in a dry upland field near 

 Trenton, N. J. They remained till the 15th, 

 when the weather became cooler and they 

 vanished. Again they came, June 26th, 

 after a rain-storm that flooded the sink-hole, 

 and were found sitting on the grass-tufts 

 and swimming in the pond by the hundred, 

 all uttering their shrill, ear-piercing groans, 

 through the day and night; but on the 

 morning of the 28th all were gone. During 

 this brief visit the frogs spawned, and the 

 eggs were found attached to blades of grass 

 and slender twigs. In about a week, those 

 of them which were not destroyed by the 

 retiring of the water were hatched out into 

 tadpoles very much like other tadpoles. As 

 they grew, about five per cent of the num- 

 ber failed to develop as rapidly as the 

 others. These " retarded " tadpoles were 

 voracious cannibals, preying upon their fel- 

 lows, now become " hoppers " and minia- 

 tures of the adult spade-foots, so extensively 

 that it was necessary to protect them to 

 save any. In due time, the water was re- 

 moved from the aquarium, and earth put in 

 its place to about an inch in depth. " Upon 

 this the young spade-foots were placed, and 

 in less than one minute many had com- 

 menced digging little burrows, into which 

 they disappeared as the excavations deep- 

 ened. ... In twenty minutes all but two of 

 forty-four specimens were below the sur- 

 face." A few individuals remained in the 

 sink-holes as the water dried up into pud- 

 dles ; but Dr. Abbott having neglected them, 

 under the supposition that they would bur- 

 row where they were, for ten days, could find 



