i8o 



SCIENCE. 



[Vol. X. No. 244 



Fremy to the increase in the proportion of the spongy tissue, the 

 thickness of the hard and dense portion of the bones continually 

 diminishing as age advances." 



This has not been my experience. Transverse sections of the 

 entire bone were made in each case, in order to test this very point, 

 by observing the relative size of dense with spongy portion, and I 

 certainly saw nothing to warrant Fremy 's conclusion. 



At the same time, small columns -J- x -J- x f inch were cut from the 

 dense portion of the shaft, and were broken transversely on a test- 

 ing-machine, in order to determine the amount of brittleness. The 

 most brittle specimen I had (No. 48), showed a rather thicker dense 

 portion than usual. 



I find the brittleness to be in the material rather than in the bone 

 as a structure, and, in view of the analytical results, I cannot ex- 

 plain that brittleness, as Von Bibra does, by holding for the gradual 

 increase in mineral salts. 



I append a very imperfect table of the results obtained on the 

 testing-machine. Every bone, as I received it, could not be cut so 

 as to give a column of the size required for breaking. It will be 

 noticed, that, in general, strength of bone diminishes as age ad- 

 vances. 

 Breaking-Weight for Column of Bone i x i x i Inch, 



BROKEN TRANSVERSELY. 



Pounds. 



25 years of age 75 



26 " " 74 



31 " " 50 



38 " " 64 



43 " " 58 



45 " " 60 



61 " " 55 



63 " " 30 



7° " " 54 



Loss of material by the burning of the laboratory affected, in a 

 measure, the completeness of the work. 



William P. Mason. 



K.ensselaer Polvtechnic Institute, 

 Troy, N.Y., July 21. 



Evidence of a Glacier-like Movement amongst Snow Particles. 



It has been conclusively proved that glaciers have a movement 

 corresponding in every way, except in amount, with that of water 

 similarly situated. I wish here to point out that snow particles, 

 under certain corresponding conditions, have the same movement 

 but of greater amount. 



It appears to me that it would be difficult to draw a line with 

 certainty between those solids whose particles are capable of such 

 movements, and those which are not. I will admit that it were 

 easy to point out this limit for solids that would show sensible 

 movement in limited time ; but to do so for solids under unHmited 

 time and large pressure might not be so easy or possible. It 

 seems unlikely that the few solids we have evidence of should be 

 the only ones possessing these movements, particularly when viewed 

 in the light of the fact that so many solids, after being transformed 

 from the molten to their solid condition, exhibit the effects of a 

 movement amongst their particles in longer or shorter periods after 

 their change of condition. It is not, however, with a consideration 

 of this limit that we have to do at present. 



In Hudson Strait we had banked around the foundation of 

 our house-walls with moss and rocks, so as to protect ourselves 

 against the weather. This bank had a slope inwards towards the 

 walls from the base. When snow remained permanently on the 

 ground, we made use of it to build up an outside wall, two feet 

 thick and eight high, over this bank, as a further protection against 

 the weather. 



Snow, it may be necessary for me to explain, exists, in northern 

 climates, under somewhat different conditions from that in which we 

 are accustomed to see it ; so that, very shortly after it has fallen, ex- 

 treme temperatures and high winds so alter it, that, whilst essentially 

 granular snow, it has become so hard that it requires an iron (not 

 a wooden) shovel to cut it, when, with sufficient care, blocks of 

 unlimited size can be hewn out of it and transported. The particles 

 are now arranged in a high degree of tension ; so much so, that, 

 when a block is struck a blow, it gives out a sound such as could 

 be compared with that given out by a brick tile. It was with 



snow in this condition that our protecting walls were built. My 

 attention was first called to a movement of the snow by noticing 

 that the snow walls were leaving the building, as I at first sup- 

 posed, by a ' topping ' movement : I therefore built relatively heavy 

 buttresses of snow to retain them, and then found that buttress 

 and wall had partaken of this movement, which was of course 

 lessened, as the buttresses had been built on comparatively level 

 ground. In addition to this, the arches which we had made over 

 the windows out of blocks of snow, of about a foot square and 

 four to five feet long, had, of their own weight, passed from the 

 arch through the straight line into very pendant inverted arches, 

 having left a space on top of the wall between the snow blocks 

 on either side, and become considerably attenuated on account of 

 the increased distance covered, and at the same time remained 

 cemented to the layer next below in the wall. W. A. Ashe. 



The Observatory, Quebec, Sept. ,26. 



Grindelia glutinosa in Wisconsin. 

 The note in Science of Sept. 23, on Grindelia sqitarrosa, re- 

 minds me of a curious fact concerning another species of Grindelia. 

 Last July I found in the Menomonee valley, near the slaughter- 

 houses west of the city of Milwaukee, a composite plant which I 

 could not find in the list of Wisconsin plants published in the first 

 volume of the ' Geology of Wisconsin.' The plant coincided com- 

 pletely with the description of Grindelia glutinosa Dicna.1 in Gray's 

 'Flora of North America' {GaniopetalcE, p. 119). I found only one 

 specimen, apparently in perfect health, growing on the Chicago, 

 Milwaukee, and St. Paul Railroad track. Gray states that the species 

 ranges along " the shore of California from Humboldt County and 

 San Francisco to Santa Barbara Islands." The seed of this speci- 

 men must have been brought to eastern Wisconsin by one of the 

 many trains which pass through the Menomonee valley to Milwau- 

 kee. It is certainly remarkable that two species of a genus not 

 before represented in Illinois and Wisconsin should have migrated 

 so far to the east of their original habitat, and should have both 

 appeared in the same summer in both States. 



W. M. Wheeler. 



Milwaukee, Sept, 26. 



Sections of Fossils. 



Having lately had occasion to consult a paper published by the 

 Geological and Natural History Survey of Canada, entitled ' Contri- 

 butions to the Micro-Paleontology of the Cambro-Silurian Rocks of 

 Canada,' by Mr. Arthur H. Foord, I wish to call attention to the 

 method there pursued. 



Having devoted considerable time to the monticuliporoid corals 

 of the Cincinnati group, I have come to the conclusion that magnified 

 views of the internal structure of these fossils are of little use in the 

 determination of species. The paper in question deals entirely with 

 these internal features. Several plates are given in illustration of new 

 species, and, out of 67 figures of 1 2 species,23 are of natural size. Many 

 of these are very poor, and would be of little value in the determi- 

 nation of species. And as now more stress is laid upon the figure 

 than the description, it follows that some of the species would be 

 unrecognizable from either the one or the other. Thin sections to 

 show the interior cannot be made without considerable skill, much 

 labor, and time ; and I think I am prepared to show, in a paper now 

 in press, that even when made the features they show under the 

 microscope are of no value whatever as specific characters. 



Joseph F. James. 



Miami University, Oxford, O., Sept. 27. 



American Caves. 



In the October Scribner, Professor Shaler states that the reason 

 caves were not used as much in North America as in Europe, was, 

 " the first peoples of this country had already attained an advance- 

 ment in the arts which enabled them to make shelters," etc. This 

 is not true. The first peoples of America were as rude as any in 

 other continents ; and the typical cave-dwellers of Europe were not 

 any more primitive than Eskimos of recent date. It is much to 

 be regretted that so erroneous an idea of ancient man in America 

 should be set forth in a popular magazine. Chas. C. Abbott. 



Trenton, N.J., Oct. i. 



