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POPULAR SCIENCE MONTHLY. 



in Ireland, which had long lain undisturbed, 

 when plowed, produced an extraordinary 

 crop of corn poppies. He thought that the 

 physical texture of the soil would probably 

 account for the long period during which the 

 seed must have lain dormant. It seemed 

 that in hard, closely packed soil seeds could 

 remain in the resting state, but that they 

 would assume their vital condition as soon 

 as the soil was loosened. Another gen- 

 tleman said that this power of seeds to 

 genninate after a dormant period threw 

 light on the glacial theory, since the seeds 

 might possibly have remained buried in the 

 quiescent state and then have germinated 

 after the flow of ice had reached farther 

 south. 



Uses of Sawdnst. The most usual and 

 extensive use of sawdust is probably as an 

 absorbent on floors and in spit-boxes, but it 

 has found many other economical applica- 

 tions. Compressed with pitch or with its 

 own intrinsic resin if it be very resinous, it 

 forms excellent kindling blocks ; it may be 

 burned as a fuel in specially prepared fire- 

 places. Fuel blocks are made by compress- 

 ing it with various substances. An artificial 

 hard wood is mentioned as formed in this 

 way. At some factories it is distilled for 

 purposes of lighting and the ammoniacal by- 

 products. Oxalic acid is made from it by 

 the process of Capitaine and Herlings. It 

 forms a valuable litter for stables, and has 

 fertilizing qualities of its own. Eggs are 

 preserved by being carefully packed in it. 

 With albumin, liquid paste, alum, bichro- 

 mate of potash, or molasses it makes excel- 

 lent briquettes ; w ith cement, lime, or gyp- 

 sum, a material for constructions ; and with 

 slaked lime, an excellent mortar. Mixed 

 half and half with sand and clay, a material 

 for partition walls and ceilings is formed. 

 Sawdust is, therefore, a very useful mate- 

 rial. 



First Uses of Gunpowder. The inven- 

 tion of gunpowder is shown by Mr. Oscar 

 Guttmann, in his book on the Manufacture 

 of Explosives, to have been most probably 

 an evolution. The Greek fire of naphtha, 

 mentioned by early European and Arabian 

 writers, ie believed to have been a composi- 



tion containing niter, sulphur, and charcoal. 

 Marcus Grgecus, who wrote in the tenth 

 century, gives a composition for charging 

 rockets and crackers closely approaching 

 that of modem blasting powder. This re- 

 ceipt is quoted by Albertus Magnus, and 

 another one, not so clear, is given by Roger 

 Bacon. None of these writers, however, 

 speak of the use of such substances in any 

 way like the firing of projectiles from guns ; 

 on the contrary, they all describe crackers 

 and bombs or maroons, and say that these 

 were discharged into towns from ballistae or 

 catapults or mangonels for the purpose of 

 setting fire to them. Mr. Guttmann has 

 found, however, in the Wardrobe Accounts 

 of King Edward III of England, an entry 

 between a. d. 1845 and 1349 giving credit 

 to one Thomas of Roldeston for the king's 

 work for his guns, for nine hundred and 

 twelve pounds of saltpeter and eight hun- 

 dred and eighty-six pounds of live sulphur. 

 This seems to confirm the tradition that 

 guns were used by the English at the battle 

 of Crecy in 1346. Mr. Guttmann decides 

 that Berthold Schwartz invented this use of 

 gunpowder about 1313; if so, Schwartz 

 must have been very young at the time, or 

 else have lived to a very great age, for the 

 date of his death is given as 1384. 



French Mnshrooms. Mushroom - grow- 

 ing in France is a matter of ancient history, 

 and the variety of mushrooms is infinite. 

 The industry originated in a peculiar way. 

 When the French began to make beds for 

 their melons they noticed that large numbers 

 of mushrooms would suddenly appear on the 

 little mounds. They proved as profitable as 

 the melons, but a crop could not be depended 

 on. A number of investigators went to work 

 to discover methods by which a fairly certain 

 and regular crop could be obtained. They have 

 partially succeeded, and the result is an in- 

 dustry very profitable to all concerned, and a 

 consumption of mushrooms in France which 

 is now something enormous. The mush- 

 room loves a cool, damp place, and light has 

 a decided effect upon its color, sunlight turn- 

 ing the surface to a reddish brown. It is 

 for these reasons that it is usually cultivated 

 in caves. In the department of the Seine 

 there are over three thousand of these sub- 

 terranean truck gardens, most of them de- 



