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THE POPULAR SCIENCE MONTHLY, 



to be made. The pellet is then laid ob- 

 liquely and pressed down by the fore-feet 

 and head of the insect, so as to cause it to 

 adhere firmly to the surface on which it is 

 building. As it proceeds, it smoothes the 

 inside of the cylinder by working with its 

 jaws and pushing the front of its flat head 

 against the plastic clay. The first section 

 being thus finished to its satisfaction, it flies 

 off to secure small spiders. It seizes a 

 spider with its fore-feet, stings it in just such 

 a way as to paralyze, without destroying its 

 life, and then deposits it in the bottom of 

 the cylinder. 



An egg is then laid beside the spider, 

 and the wasp flies off to secure other spi- 

 ders. This is continued until the cavity, 

 which holds from twelve to fifteen of the 

 smaller kinds, is full. The wasp then 

 covers the open end with a cap of the same 

 material as before, after which it adds other 

 sections to the number of three or four, fill- 

 ing each with spiders and depositing one 

 egg in each. The young larva feeds on 

 these paralyzed spiders, and, as it seems, 

 requires from twelve to fifteen of them to 

 nourish it until it is ready to become a 

 pupa. Unlike some other clay-nest build- 

 ers, this wasp does not nurse its young, but 

 they are securely sealed up id the sections, 

 and feed themselves. When ready to come 

 forth, the wasp gnaws a round hole in the 

 wall of its cell, and issues forth as a perfect 

 insect. 



The Uses of Baryta. — Baryta is an alka- 

 line earth of a gray color, not easily fusible, 

 and poisonous. Its various salts are exten- 

 sively used in the arts, as will be seen from 

 a paper read by Dr. Lewis Feuchtwanger, 

 before the Polytechnic Club, of which we 

 present a synopsis. The sulphate of baryta, 

 66 per cent, of baryta and 34 of sulphuric 

 acid, is the only baryta-salt that is not poi- 

 sonous. It is abundant in England, France, 

 Germany, and the United States, where it 

 usually occurs in connection with beds or 

 veins of metallic ores, as gangue, or vein- 

 stone. Sometimes, however, it forms dis- 

 tinct veins, in company with the secondary 

 limestone, and very often in fine crystals, 

 along with calcite and celestine. Connecti- 

 cut and Missouri have long furnished abun- 

 dant material for the arts. Next come 



Virginia, New York, New Hampshire, Mas- 

 sachusetts, Pennsylvania, Kentucky, and 

 Tennessee. The variety known as " Bologna \ 

 spar " is an ornamental stone, of a brown 

 color, and concentric rings, originally found 

 in a bed of clay near Bologna. The sul- 

 phate of baryta also often occurs associated 

 with lime, and some silica and alum, and is 

 then called calcareobaryte ; when associated 

 with strontia it is called baryto-celestine. 



Witherite is a carbonate of baryta, con- 

 sisting of IS per cent, baryta and 22 car- 

 bonic acid. It is found, in considerable 

 quantities, in England, Silesia, Hungary, 

 Sicily, and Chili, but not much in the United 

 States. It is largely used in plate-glass 

 manufacture in France, as also in the man- 

 ufacture of beet-root sugar, and permanent 

 while. Latterly, it has come into use for 

 paint, in combination with soluble glass and 

 white oxide of zinc. The metallic base of 

 these salts is barium. It is a white, malle- 

 able, and fusible metal, readily oxidizing 

 in air, and decomposing water at common 

 temperature. The pure baryta, oxide of 

 barium, is used for the production of per- 

 oxide of hydrogen, which is much recom- 

 mended as a medicinal reagent, and employed 

 in the arts for bleaching animal tissue, and 

 converting brown into blond hair. The 

 oxide, or caustic baryta, rivals, in caustic 

 properties, potash, soda, and ammonia. 



The chloride of barium is got by fusing 

 the sulphate of baryta with chloride of cal- 

 cium, in a reverberatory furnace, and then 

 extracting with hot water, leaving the sul- 

 phate of lime undissolved. Chlorate of ba- 

 ryta, used in pyrotechny, and which burns 

 with a green flame, is prepared by dissolving 

 artificial carbonate of baryta in chloric acid 

 solution. Nitrate of baryta, likewise used 

 in pyrotechny, may be got by dissolving the 

 native carbonate in nitric acid and evaporat- 

 ing the solution, octahedral crystals being 

 deposited. The native sulphate of baryta 

 is used to adulterate white lead, often to 

 the extent of 25 to 50 per cent. 



The artificial sulphate, permanent white, 

 is much used in the manufacture of a paper 

 of the purest white, for collars, cards, etc. 

 In copper metallurgical operations, the sul- 

 phide of barium has latterly been employed 

 for the purpose of precipitating from an 

 ammoniacal copper solution the copper as a 



