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THE POPULAR SCIENCE MONTHLY. 



been buried with the vessel for about a 

 thousand years, yet they retained their 

 structure unimpaired, only they had become 

 browned, or turned to brown-coal, and were 

 easily identified as belonging to Hypnum 

 squarrosum, Clirnacium deiidroides, and oth- 

 er common species. No difficulty was met 

 in making a satisfactory microscopical exam- 

 ination of them, and the cell-structure was 

 brought out as plainly as if they had been 

 freshly gathered. These, however, were 

 only some of the more recent among several 

 ancient specimens of peat-mosses that Dr. 

 Miiller reports that he has examined with 

 similar results. The mosses of a tuft sup- 

 posed to be from the lake-dwellings re- 

 tained the individuality of their parts ; and 

 in a tuft taken from the turf under the drift 

 in the Baltic provinces of Prussia, the 

 plants, older by hundreds of thousands of 

 years than the other specimens, were so 

 well preserved that they were easily recog- 

 nized by their form and cell-structure as 

 belonging to a Scandinavian species of al- 

 most exclusively Arctic growth, which must 

 have come down in the glacial period. We 

 are often surprised at the good condition in 

 which the unfossilized bones of prehistoric 

 men and animals arc sometimes found ; but 

 the beautifully preserved condition in which 

 these mosses occur is a far more wonderful 

 phenomenon, because those organisms are 

 among the plants of the slightest structure, 

 and are not subject to fossilization. Still 

 more wonderful is the perfection with which 

 the minute structure of the diatoms is pre- 

 served. 



Soldering by Pressure. It is known 

 that Faraday, in 1850, observed that two 

 pieces of ice brought in contact and sub- 

 jected to pressure would be soldered to- 

 gether, and unite into a homogeneous 

 mass. This soldering, which took place the 

 more readily in proportion as the pieces of 

 ice wore nearer their melting-point, was re- 

 garded by Faraday as due to a special prop- 

 erty of ice. Mr. W. Spring has recently 

 undertaken a methodical series of experi- 

 ments in the compression of a variety of 

 bodies. That their condition of division 

 might be well established, he reduced the 

 substances experimented upon to powder, 

 and subjected them in a mold of steel to a 

 pressure of between two thousand and seven 



thousand atmospheres. Filings of lead 

 were converted at two thousand atmos- 

 pheres into a solid block, showing no granu- 

 lation under the microscope, with a densi- 

 ty slightly above that of ordinary lead. At 

 five thousand atmospheres the lead became 

 like a liquid, and ran into all the interstices 

 of the apparatus. Powders of zinc and bis- 

 muth at five to six thousand atmospheres 

 gave solid blocks, with a crystalline fract- 

 ure. Approaching six thousand atmos- 

 pheres, zinc and tin seemed to liquefy. 

 Powder of prismatic sulphur was converted 

 into a solid block of octahedric sulphur. 

 Slack sulphur and octahedric sulphur passed 

 into the same condition. Bed phosphorus 

 passed into the denser state of black phos- 

 phorus. Thus, simple bodies undergo chem- 

 ical transformations under the simple ac- 

 tion of pressure. The transformation of 

 amorphous powders, like that of zinc, into 

 crystalline masses, is a kind of auto-com- 

 bination. Some of the hard metals never 

 lose their pulverulent structure under any 

 pressure. Powders of the bioxide of man- 

 ganese and the sulphurets of zinc and lead 

 solder under pressure, and present the aspect 

 of natural crystalline pyrolusite, blende, and 

 galena ; while silica and the oxides and sul- 

 phurets of arsenic do not suffer any agglom- 

 eration. Some pulverized salts are solidified 

 by pressure, and become transparent. Hy- 

 drated salts as, for example, sulphate of 

 soda may be completely liquefied at a high 

 pressure. Certain organic substances the 

 fatty acids, moist cotton, and starch change 

 their appearance, lose their texture, and 

 undergo a very evident molecular packing. 



NOTES. 



TriE city of Charleston, South Carolina, 

 according to the annual review of Mayor 

 Courtenay, is paying a much higher relative 

 rate for school purposes than Northern cit- 

 ies which have secured for themselves great- 

 er educational advantages. Compared with 

 Boston, it gives, in proportion, nearly one 

 half as much again for its primary public 

 schools alone as that city for all its schools, 

 and gives, besides, annual appropriations 

 to the High School and Charleston College. 

 The grievous burden has been thrown upon 

 the city by the extraordinary needs of the 

 colored population, and gives it, the city offi- 

 cers believe, a right to call upon the Govern- 

 ment for help. 



