POPULAR MISCELLANY. 



573 



dissolves in water, or into delicate, viscous, 

 and somewhat tough superficial lamina?. 

 Without using any Mordant, it produces 

 very fast colors in wool, silk, cotton, and 

 linen goods, varying, according to the appli- 

 cation, from the clearest to the blackest 

 brown. The corovillo affords a deep scarlet 

 color, the preparation and application of 

 which are a secret known only to a few fam- 

 ilies who keep it well. The acid extract 

 from the lapacho lapachic acid appearing 

 in greenish-yellow needle-crystals, affords, 

 according to its treatment, rose-crimson, 

 yellow, clear brown, and dark brown. The 

 tree itself has some remarkable character- 

 istics in the impenetrable density of its in- 

 florescence previous to the appearance of 

 the leaves, the firmness and strength of its 

 wood and its freedom from ash, the resist- 

 ance of the wood to decay, and the intense 

 induration of its wood when soaked for a 

 considerable time in water. 



Speed Of Insects. "Flies," observes a 

 writer in the London Spectator, "frequent 

 the insides of our windows, buzzing slug- 

 gishly in and out of the room. But what 

 different creatures are they when they ac- 

 company your horse on a hot summer's day ! 

 A swarm of these little pests keep perti- 

 naciously on wing about your horse's ears ; 

 quicken the pace up to ten or twelve miles 

 an hour, still they are there ; let a gust of 

 wind arise and carry them backward and 

 behind, the breeze having dropped, their 

 speed is redoubled, and they return to their 

 post of annoyance to the poor horse. But 

 this example gives only a partial proof of 

 the fly's power of flight. The present writer 

 was traveling one day in autumn by rail at 

 about twenty-five miles an hour, when a 

 company of flies put in an appearance at 

 the carriage-window. They never settled, 

 but easily kept pace with the train ; so 

 much so, indeed, that their flight seemed to 

 be almost mechanical, and a thought struck 

 the writer that they had probably been 

 drawn into a kind of vortex, whereby they 

 were drawn onward with little exertion on 

 the part of themselves. But this notion 

 was soon disproved. They sallied forth at 

 right angles from the carriage, flew to a dis- 

 tance of thirty or forty feet, still keeping 

 pace, and then returned with increased 



speed and buoyancy to the window." The 

 same writer estimates that the dragon-fly, 

 which passes and repasses as in instantane- 

 ous jerks, is capable of flying at a speed of 

 from eighty to a hundred miles an hour. 



Ambergris. The word ambergris is 

 French for gray amber, which is a misnomer, 

 for ambergris is a very different substance 

 from amber. The latter is fossilized resin, 

 and is therefore of vegetable origin, while 

 the former is a product of some disease in 

 the sperm whale. Ambergris is sometimes 

 found in the intestines of the whale, but 

 most of the supply is picked up in masses 

 which float on the surface of tropical seas. 

 The best ambergris is soft and waxy, gray 

 in color, and streaked with different shades. 

 It is opaque, inflammable, and remarkably 

 light. It is found in the largest quantities 

 near the Bahamas, but it is a scarce article 

 at best, being quoted in New York at thirty- 

 four dollars an ounce, wholesale. Its use is 

 in perfumery, its great value being due to 

 its powerful odor, which somewhat resembles 

 that of musk, but is much more lasting. It 

 is so peculiar that it has never been success- 

 fully imitated. Ambergris is so costly that 

 it is one of the most adulterated articles 

 known in commerce. It is too costly to use 

 alone, but a small quantity of its solution in 

 alcohol is mixed with other perfumes, the 

 blended odor of which it intensifies. A grain 

 or two rubbed down with sugar is often add- 

 ed to a hogshead of wine, to which it gives a 

 pleasing fragrance. A handkerchief per- 

 fumed with the famous Parisian compound 

 perfume, extrait d'ambre, will retain the odor 

 after several washings. 



Strength of the Earth's Crnst. In esti- 

 mating the strength of the earth's crust, 

 Mr. G. K. Gilbert uses the term crust to in- 

 dicate the outside part of the earth, without 

 reference to the question whether it differs 

 in constitution from the interior. The con- 

 ditions of the problem are illustrated by 

 supposing a large tank of paraffin with level 

 surface. If a hole be dug in this and the 

 material piled up at one side, the perma- 

 nence of the hole or heap will depend on its 

 magnitude. Beyond a certain limit, further 

 excavation and heaping will be compensated 

 by the flow of the material. Substitute for 



