Cope.] ^4:^ [May 6, 



enemy's lines of circumvallation, or line of battle, with the wind 

 blowing in his direction, the balloon could be sent up with ballast 

 proportioned to the general elevation intended for its soaring over 

 his position. I have said '' general elevation," because change of 

 volume in the balloon, in accordance with the change of tempera- 

 ture, or increased weight on it, from an accession of moisture, pre- 

 clude the possibility of calculating upon obtaining precise prede- 

 termined elevation for the balloon. The weight of the string for 

 the length to be paid out to the contemplated distance would of 

 course enter into the amount of ballast needed to secure an 

 approximately special elevation at a special distance. The distance 

 to the enemy's position being known, and the vertical angle being 

 taken to the balloon from its point of departure, when it is approxi- 

 mately delivered at its destination, the exact remaining length of 

 string, wiih allowance for sagging, necessary to pay out so as to 

 cause the balloon fairly to dominate the enemy's military works or 

 line of battle, would at once be known by a simple computation, 

 or could be taken from a table of angles and distances. This 

 operation being completely performed at several points along the 

 opposing military lines, a series of pictures, at varying distances 

 from front to rear, and from right to left of the enemy's position 

 could be secured by means of the electro-magnetic attachment to 

 the shutters of the photographic cameras, each individual one of 

 which could take a number of pictures without replenishment of 

 plates. It is evident that such a use of the balloon and the photo- 

 graphic camera would have proved greatly advantageous to either 

 side in such modern sieges as those of Sebastopol, Richmond, and 

 Paris. 



0)1 the Skull of the Dinosaurian Lcelaps incrassatus Cope. 



By E. D. Cope. 



{Read before the American Philosophical Society, May 6, 1892.) 



The characters of the skull in the carnivorous Dinosauria are only par- 

 tially known, so the present opportunity is improved to add to our knowl- 

 edge a considerable number of points, if not to exhaust the subject. I 

 have temporarily in my possession two incomplete crania of tlie Lwlaps 

 incrassatuK, from tlie Laramie formation of the Red Deer river, in the 

 Dominion of Canada, which have been submitted to me by the Geological 



