POPULAR MISCELLANY. 



24.7 



eter of the dome is from seven to eight inch- 

 es at the base, and its height is about the 

 same. The inhabitant of this most curious 

 structure is thus described by our author: 

 " The fore-part of the body, cephalothorax, 

 is of a golden-yellow color, bordered and 

 marked with blackish bands. The legs are 

 of a delicate green, having the thighs 

 marked by blackish longitudinal bands, and 

 blackish annuli at the joints. On the back 

 of the abdomen the coloi'S within the black- 

 ish marginal lines are as follows: at the 

 base, next the cephalothorax, a snowy 

 white ; the middle lobes are a light yellow, 

 the lower lobes and the cruciform figure are 

 a golden yellow. The bands and markings 

 on the side of the abdomen are in the fol- 

 lowing order from the top, viz., crimson, 

 white, dark green with light-green edges, 

 blackish to dark green, yellow." But in the 

 mind of the araneologist the special inte- 

 rest of the basilica spider is not its archi- 

 tectural skill, not its beautiful markings, 

 but the fact that it seems to form a link be- 

 tween the orb-weaving and the line-weaving 

 spiders. 



Mannfactnre of Sea-Salt in San Fran- 

 ciscOi — At Rock Island, in the bay of San 

 Francisco, works have lately been estab- 

 lished for reducing salt from sea-water by 

 solar evaporation. The process of evap- 

 orating the salt-water is described as fol- 

 lows in the Engineering and Mining Jour- 

 nal: "■ The water is let into a large reservoir 

 at high tide, and thence passed into a series 

 of other reservoirs, until it has traversed a 

 distance of fifteen to twenty miles, in the 

 mean time steadily increasing in strength and 

 dropping its limy impurities. In the fourth 

 reservoir the specific gravity is 16°, and it 

 leaves the seventh when it is 25°. Pure 

 chloride of sodium begins to form when the 

 brine attains this density, and continues to 

 do so until it has attained 29°. During the 

 strengthening of the sea-water from its nat- 

 ural specific gravity of about 1.03 to 25, the 

 sulphate of lime held in solution crystallizes 

 and settles to the bottom. It is not until a 

 specific gravity of 29 is reached that chlo- 

 ride and sulphate of magnesia, bromide of 

 soda, and chloride of potassium, begin to 

 concrete. These being the principal if not 

 the only impurities, with the exception of a 



little water, the manner of securing pure 

 salt appears very simple. When at 25°, 

 the pickle is run into crystallizing ponds or 

 vats, some of which are simply the earth 

 hollowed for the purpose ; others are board- 

 ed on the bottom, while a third is made 

 wholly of boards. In these the brine is 

 allowed to remain until it is 28|°, when the 

 salt which has formed in the bottom is 

 shoveled into baskets, loaded on cars, and 

 conveyed to another part of the island 

 nearer the wharf, where it is piled up in 

 great pyramidal-shaped mounds. These 

 remain exposed to the sun and weather for 

 a year, which whitens and purifies the crys- 

 tals preparatory to grinding." 



Atmospheric Electricity and Plant - 

 Growth. — Atmospheric electricity is, accord- 

 ing to M. Grandeau, a powerful agent in the 

 process of assimilation in plants. Plants 

 protected from its influence build up fifty 

 to sixty per cent, less of nitrogenous matter 

 than those subject to ordinary conditions ; 

 the proportion of ash is higher and of water 

 lower. In the author's experiments differ- 

 ent species of growing plants were inclosed 

 within an electric screen consisting of four 

 triangles of iron. The plants experimented 

 upon were maize, tobacco, and wheat — two 

 specimens of each — of which the one was 

 screened from atmospheric electricity, the 

 other not. The results of these experiments 

 agree fully with the discovery made some 

 time ago by Berthelot, that free nitrogen 

 unites with organic matter under the action 

 of electric currents not only from ordinary 

 induction-coils, but even from feeble voltaic 

 batteries. The proportion of nitrogen thus 

 fixed in seven months in paper and dextrine 

 was 1.92 thousandths. 



Pnre Teas. — The Chinese minister at 

 Washington, Chin-Lan Pin, was lately vis- 

 ited by a delegation representing a firm of 

 tea-importers in Baltimore, who wished to 

 learn his views regarding the importation 

 into this country of pure teas. The minis- 

 ter in his reply said that the various brands 

 of tea sold in America and Europe are un- 

 known to and not used by the tea-consumer 

 in China. They are specially prepared by 

 the Chinese tea-exporters for the foreign 

 market. They are colored by the use of 



