FRAGMENTS OF SCIENCE. 



621 



the composition, and on top of all came 

 the Normans. These elements, none of 

 which Avere extremely discordant with 

 the others, became thoroughly mixed in 

 the course of time, and matured into the 

 English people as it is. The English 

 resemble the Romans in their methods 

 of colonization, political tact, practical 

 sense, persistence, religious tolerance, 

 the magnitude of their works and the 

 boldness of their undertakings, and in 

 their egotism working together with the 

 principle of social solidarity. Both read- 

 ily established themselves in new colo- 

 nies, carrying there the civilization of 

 the mother country and their systems 

 of administration. The great roads and 

 wonderful bridges constructed by the 

 Romans are paralleled by the great 

 Anglo-Saxon railway systems. As the 

 Latin language became almost univer- 

 sal, so the English language is diffusing 

 itself everywhere. But Signor Sergi fails 

 to show why, if the English have taken 

 so much from the Romans, the Italians, 

 their direct descendants, have lost so 

 much of what they once had. He re- 

 serves that question, after raising it, for 

 future consideration. 



Carbonic Acid and Climate. — The 

 great importance of the carbonic acid 

 in the atmosphere as a factor in deter- 

 mining the climate of the earth has 

 been confirmed by the researches of a 

 considerable number of investigators. 

 Its work appears to be that of an ab- 

 sorbent of the sun's radiant heat, retain- 

 ing it and preventing its passing by us 

 and leaving us in the cold temperature 

 of space. Tyndall computes that it has 

 in this capacity a power eighty times 

 that of oxygen or nitrogen, while it is 

 excelled by water vapor with ninety- 

 two times that of those gases. Lecher 

 and Pretner, on the other hand, believe 

 that carbonic acid is the only agent 

 concerned in the service. Mr. Cyrus F. 

 Talman, Jr., in view of the fact that 

 carbonic acid is an important factor 

 among geological agencies, has pub- 

 lished, in the Journal of Geology, a 

 study of the conditions of the content 

 of that gas in the ocean, a study that 

 leads to the consideration of the chem- 

 istry of the ocean. It seems to be clear 

 that with falling temperature the ocean 

 will dissolve carbonic acid from the air. 

 Dr. T. C. Charaberliu has shown that 



the amount of carbonic acid in the at- 

 mosphere at any one time, and therefore 

 the climate of the earth at that time, 

 depends upon the value of the ratio of 

 the supply of the gas to its depletion. 

 Besides the continuous supply that the 

 atmosphere receives from the interior of 

 the earth and from planetary space and 

 the continuous depletion due to the for- 

 mation of carbonates in place of the 

 igneous alkali earth silicates, there are 

 variations in the ratio of supply to de- 

 pletion dependent upon the attitude of 

 the land and the water. A large expos- 

 ure of land surface is correlated with a 

 rapid solution of calcium and magne- 

 sium carbonates, which, becoming bicar- 

 bonates, represent a loss of carbonic 

 acid to the atmosphere. On the other 

 hand, the formation of the normal car- 

 bonate by lime-secreting animals causes 

 a direct liberation of the second equiva- 

 lent of the bicarbonate. Therefore ex- 

 tensive oceans and abundant marine 

 life are correlated with warm climate. 

 After a somewhat more minute discus- 

 sion of the action, Mr. Talman con- 

 cludes that the ocean very greatly in- 

 tensifies the secular variation of the 

 earth's temperature, although acting as 

 a moderating agent in the minor cycles. 



Pearl Mussels. — In his report to 

 the United States Fish Commission on 

 the Pearly Fresh-Water Mussels of the 

 United States, Mr. Charles T. Simpson 

 speaks of the great variety of conditions 

 under which they live. Thej' show 

 great capacity for adaptation. Most of 

 them are found in shallow water, but 

 certain forms live at considerable 

 depths. Some bury themselves among 

 the fibrous roots of trees, some in the 

 muddy, sandy banks just below the sur- 

 face of the water, and some, as in Lake 

 Tiberias (Palestine) and Lake Tangan- 

 yika (Africa), under six hundred or 

 more feet of water. Ordinarily they die 

 in a very short time if taken out of the 

 water — in from twentj^-four to forty- 

 eight hours, as a rule — and they gener- 

 ally die in a few hours when exposed to 

 the sun. But many species, thus ten- 

 der in the open air, will lie buried in 

 dried mud for a long time. In June, 

 1850, a li^^ng pond mussel was sent to 

 London, from Australia, which had been 

 out of water for more than a year. 

 Along a small stream near Braidentown, 



