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THE POPULAR SCIENCE MONTHLY. 



Bay of Fundy, coast of Maine, Boston basin, 

 and the central Carolinas ; while the western 

 belt crosses the Eastern Townships and fol- 

 lows the Blue Rido;e through southern Penn- 

 sylvania, Maryland, Virginia, and North 

 Carolina, to Georgia. Further and fuller 

 Studies of the subject are desired by the 

 author, who remarks that the identification 

 of truly volcanic rocks in highly or partly 

 crystalline terrains possesses far more than 

 a petrographical significance, since, by fixing 

 what was the surface at the time of their 

 formation, they furnish a certain datum for 

 tracing out the sequence of later geographic 

 changes and geological develof)ment. 



A " Copper Ago." An account of the 

 discoveries made at Tel-el-Heji, the site of 

 the ancient city of Lachish, in Palestine, 

 gave rise, in the British Association, to a 

 discussion concerning a proljable copper age. 

 The very high mound contains the ruins of 

 several towns, built each (except the lowest) 

 on the ruined remains of its predecessor 

 The uppermost was an Israelitish town, and 

 was very probably the remains of the La- 

 chish which was besieged and destroyed by 

 Sennacherib in the tmie of Hezekiah. 

 Throughout the mound, from the bottom to 

 the top, were found flint and metallic imple- 

 ments. Among them was a thick chisel 

 made of copper, which had been hardened 

 by mixture ^^ ith red oxide of copper, from 

 which it received a red appearance. Toward 

 the top of the mound were bronze arrow- 

 heads, which probably dated back to between 

 1400 and 1501) years b. c. In the ascent of 

 the mound a change was observed from cop- 

 per to bronze and from ))ronze to iron, 

 which Avas very common in the Israelitish 

 town. Lead was found in the form of a 

 thick wire, very pure. A silver bangle con- 

 tained ninety per cent of silver, considerable 

 copper, and an aijpreciable quantity of gold. 

 Sir John Evans s})oke of the evidences of a 

 copper age preceding a bronze age, seen in 

 North America, Ireland, Hungary, and other 

 countries. Dr. Ilildebrand said that several 

 implements of pure copper had been found in 

 Sweden. Prof. Boyd Dawkins thought the 

 evidence from North America showed that 

 the copper age was practically a side of the 

 neolithic age. Frjt. A. H. Sayce spoke of 

 the absence of words for tin in the Egyptian 



and Assyrian languages, although the metal 

 was known in Egypt as far back as the 

 eighteenth dynasty, and although there are 

 words in both languages for gold, silver, 

 iron, copper, bronze, lead, and possibly me- 

 tallic antimony. The word for iron in Egyp- 

 tian meant metal from heaven, and in Assyr- 

 ian, heavenly metal. This would indicate 

 that their iron was meteoric. 



Feats of Diving Birds. Naval archi- 

 tects are credited with saying that the high- 

 est speed in navigation could be obtained by 

 suljmariue boats. The principle is illus- 

 trated in tlie diving birds, which are capable 

 of shooting through the water with amazing 

 velocity. While these birds live by catch- 

 ing fish in deep water far below the surface, 

 they present many differences in outer ap- 

 pearance. In the collection at the London 

 Zoological Gardens are black-footed pen- 

 guins, guillemots, " darters," a puffin, and a 

 cormorant. The penguin can not fly in the 

 air, can not walk, but hops as if its feet 

 were tied together ; and can not swim ; and 

 can only with any grace fly under water. 

 When the keeper of their quarters appears 

 to feed the birds, they each behave in their 

 characteristic way. The fish thrown into 

 the water, the penguins instantly plunge be- 

 neath, when an astonishing change takes 

 place, thus described by a writer in the 

 Spectator : " The slow, ungainly bird is 

 transformed into a swift and beautiful crea- 

 ture, beaded with globules of quicksilver, 

 where the air clings to the close feathers, and 

 fl/ing through the clear and waveless depths 

 with arrowy speed and powers of turning 

 far greater than in any known form of 

 aerial flight. The rapid and steady'strokes 

 of the wings are exactly similar to those of 

 the air birds, while the feet float straight 

 out, level with its body, unused for propul- 

 sion, or even as rudders, and as little need- 

 ed in its progress as tliose of a wild duck 

 when on the wing. The twists and turns 

 necessary to follow the active little fish are 

 made wholly by the strokes of one wing and 

 the cessation of movement in the other ; and 

 the fish are chased, caught, and swallowed 

 without the slightest relaxation of speed, in a 

 submarine flight which is quite as rapid as 

 that of most birds which take their prey in 

 midair." The head and shoulders mav be 



