220 



SCIENCE. 



[Vol. VII., No. 161 



poem?, romances, or general reading-matter, — it is 

 the right and duty of congress, under the general 

 urgency clauses of the constitution, to at once enact 

 statutes for the public welfare and relief. 



It has never been denied, I think, that, in times of 

 great dearth or stress or suffering, extraordinary 

 powers can be construed into that clause, for the gen- 

 eral good of the whole people. 



It seems to me, however, that there is no doubt 

 possible but that congress would have power to sim- 

 ply amend its present copyright act by substituting 

 the word ' person ' for the words ' citizen of the 

 United States,' which would at once give a perfect 

 and absolute international copyright, and the best 

 one possible ; since any new and separate act would 

 at once be brought before the courts for construc- 

 tion, whereas the word ' person ' could hardly need 

 judicial interpretation. This was the plan suggested 

 by me in 1875, and I have seen no reason to depart 

 from it since. Appleton Morgan. 



A recent ice-storm. 



In answer to the question of Mr. W. M. Davis, 

 printed, on p. 190 of Science (vii. No. 160), I would 

 suggest the following, deduced, from observations of 

 the effects of many similar storms, though the par- 

 ticular storm referred to, of Feb. 11-13, did not 

 trouble the trees so much in this neighborhood as 

 farther inland and farther north ; for the tempera- 

 ture near Boston was not quite low enough to form 

 much ice at that time. 



Pine-trees make branches nearly at right angles 

 with their trunks, and these branches become more 

 and more pendant in their habit as they grow older. 

 It follows, that, when an old tree is loaded down 

 with ice, the branches can bend downward till they 

 rest part of their weight on those below, and the 

 lowest ones on the ground, without any abrupt bend- 

 ing at any one point. Moreover, pine wood, when 

 alive, is quite tough, and will bear a good deal of 

 distortion without fracture. The same reasons op- 

 erate to protect our other coniferous trees of the 

 spruce and fir tribes. 



The white-oaks, although peculiar in retaining a 

 good deal of th^ir last year's foliage in winter, and 

 carrying thereby a heavy load of ice on such occa- 

 sions, have a prodigiously strong fibre, and, when 

 alive, the branches possess great toughness. Any- 

 one who has tried to break a small limb from a living 

 white-oak tree knows that it is nearly impossible. 

 The white-oaks of Worcester county, Mass., are 

 famed for the hardness and toughness of their wood, 

 which is fully twice as strong to resist fracture while 

 green as that of the white-oaks of the western states, 

 though probably similar to the same kind of oaks 

 growing near the same latitude, and as near the sea 

 in other states. 



On the other hand, the maples, elms, ashes, beeches, 

 and many other deciduous trees which abound in the 

 district referred to by Mr. Davis, make branches 

 that pursue an upward direction, and continue to 

 bifurcate, as they grow upward, at small angles 

 both with one another and with the parent stem 

 or trunk ; while their fibre lacks toughness, i.e., is 

 easily split in most cases. When these upright 

 branches bend downward with the load of ice, the 

 mechanical problem is quite different from that ex- 

 isting in the pines and spruces : for, as the branches 

 of these evergreens become more and more pendant, 



their centres of gravity, after getting below their 

 point of origin, as they soon do, approach the trunk, 

 and therefore exert less and less leverage the more 

 they bend : while in the case of a beech, ash, maple, 

 or elm tree, the centres of gravity of the upright 

 branches depart from the vertical line of the trunk 

 or point of bifurcation, and gain in leverage to effect 

 fracture as they bend down, till they pass the hori- 

 zontal ; and then resistance to splitting is so feeble, 

 that they often split at the fork before getting down 

 as far as a horizontal position. 



Among ornamental trees are some of peculiarly 

 weak fibre which suffer extremely from ice breakage. 

 Such is the Virgilia lutea, of which I have some large 

 specimens thus mutilated, though still very beautiful 

 trees in June. Edwd. S. Philbrick. 



Brookline, Mass., March 1. 



Habits of batrachians. 



I have been unable to obtain information regarding 

 the habits of the Amphiumidaeof the United States, — 

 Cryptobranchus or Menopoma, Amphiuma, Necturus, 

 Siren, etc. (hellbenders, mudpuppies, etc.). Can any 

 of the readers of Science tell where and when they 

 are common, their larval habits, egg-laying habits 

 and seasons, etc. ? George Baur. 



Yale coll. museum, New Haven, Conn. 



A tornado brood in Hampshire county, Mass. 



I find some additional notes, made at the time, 

 from which it appears that the storm resulting in the 

 destruction of Northampton bridge, June 14, 1877, 

 exhibited at first a whirl in the shape of a huge um- 

 brella hanging from the main cloud, the convexity 

 upward : its destructive career may therefore be 

 interpreted as a tornado. I find, also, notes of a 

 tornado at Westfield, July 9 of the same year. This 

 was reported as coming down the gorge of the West- 

 field Eiver, and thus confirms my view of the origin 

 of the tornadoes I described (Science, Feb. 5) as hav- 

 ing their point of departure over the Mill Eiver 

 branch-valley. H. W. P. 



1 Marvels of animal life.' 



In a notice of ' Marvels of animal life,' in Science 

 of Jan. 1, your reviewer says, "It will surprise some 

 readers to see man and the Pteranodon represented 

 on plate 31 as contemporaneous." The human figure 

 was introduced in the cut merely to give young 

 people some idea of the size of the animal, and was 

 intended to have no other significance, the omission 

 of this explanation in the text being an oversight. 



C. F. Holder. 



Pasadena, Cal., Feb. 17. 



The competition of convict labor. 



In reading Mr. Langerfeld's letter in Science of 

 Feb. 19, one point occurs to me. He finds fault with 

 my arithmetic. Now, I made it clear in one of the 

 earlier articles that the competing power of convicts 

 was in this country only about sixty per cent of what 

 their numerical strength would seem to give them. 

 In my letter printed in your issue of Feb. 12, all this 

 was taken for granted, as I was unwilling to cumber 

 your space with a repetition. 



Nicholas Murray Butler. 



New York, Feb. 25. 



