572 



SCIENCE. 



[N. S. Vol. XXII. No. 566. 



fall very slowly in the air. Theoretically, a 

 small spherical body should fall at the same 

 rate as a large spherical body of the same 

 composition; but it does not, and this may 

 easily be demonstrated by throwing a shovelful 

 of coal composed of pellets of various sizes — 

 some as fine as diist — into the air at a height 

 of even six or eight feet. The very finest dust 

 floats for some time in the air, and the largest 

 pellets reach the ground first. It is indeed 

 due to this surface attraction that small 

 bodies like pollen grains, fungiis spores and 

 the like, are capable of being transported 

 through the air over such great distances. 



J. B. Dandeno. 

 Agricultural College, Michigan, 

 April 3, 1905. 



THE WEIGHT OF THE BRONTOSAURUS. 



At the request of Professor H. F. Osborn 

 the writer undertook to make an estimate of 

 the probable weight in the flesh of a Bronto- 

 saurus excelsus. The mounted skeleton in the 

 American Museum is 66 feet 7 inches long, 

 and from this a very carefully studied model 

 or restoration was made by Mr. Charles E. 

 Knight, who also made use of Dr. W. D. Mat- 

 thew's studies upon the probable size and ar- 

 rangement of the muscles in this animal. The 

 skeleton was mounted after the prolonged 

 study and discussion of a number of special- 

 ists; its contours are strikingly lifelike, and 

 Mr. linight's long training well qualified him 

 to infer the external contours of an animal 

 from its internal framework. Hence the 

 model should correspond fairly well with the 

 animal itself. 



From the model, a number of plaster casts 

 were made, and one of these was used in the 

 following determination. The model was con- 

 structed as nearly as possible to the exact 

 scale of one. sixteenth natural size, hence the 

 cubic contents of the model multiplied by the 

 cube of 16 (4096) should indicate the probable 

 volume of water which would be displaced by 

 the animal in the flesh. One of the casts was 

 cut into six pieces of convenient size, which 

 were then made water-tight by a double coat- 

 ing of shellac. Professor William Hallock 

 very kindly consented to determine accurately 



the cubic contents of these pieces in one of the 

 physical laboratories at Columbia University. 



The weight of the cast in air minus its 

 weight in water would equal the weight of an 

 equal volume of water. This differential 

 weight was determined in grams. As a 

 gram is the weight of a cubic centimeter 

 of water the weight of the water displaced gave 

 directly the cubic contents of the model. Pro- 

 fessor Hallock found the weight of the water 

 displaced to be 7,595 grams (about .27 cubic 

 feet), or say 7.6 kilograms. Hence the animal 

 itself would displace 7,595 X (16)' = 31,129,- 

 600 c.c. or 31.13 metric tons. Converting this 

 into tons, we have 31.13X2,200-^-2,000 = 

 32.24, or siay 34J tons, as the estimated weight 

 of the water displaced by the. animal. But 

 as the animal was probably slightly heavier 

 than the water displaced, in order to enable it 

 to walk on the bottom along the shore of lakes 

 and rivers, we may add about ten per cent, 

 to 34^- tons, securing as a final estimate 38 

 tons. 



This result accords very well with Mr. F. A. 

 Lucas's careful estimate of the weight of a 

 75-foot sulphur bottom whale, an animal of 

 much greater bulk than the Brontosaurus. 

 This weighed about 63 tons, and- in conversa- 

 tion with the writer Mr. Lucas expressed the 

 opinion that the Brontosaurus did not weigh 

 ' much more than half as much.' This opinion 

 seems justified by the estimate given above. 



W. K. Gregory. 

 American Museum of Natural History, 

 New York, 



September 30, 1905. 



QUOTATIONS. 



college administration. 

 Of the several conferences of the installa- 

 tion week at Champaign-Urbana, the one an- 

 nounced as a conference of trustees to con- 

 sider methods of administration builded larger 

 and possibly better than it knew. It included 

 not alone the problems of the conduct of the 

 business machinery of these great corporations, 

 but raised the fundamental issues in regard to 

 raison d'etre of boards and presidents, and 

 administrative means and measures. And it 

 raised the most pertinent query as to the 



