Chemistry and Physics. 408 



pentadactyle Dinoceras are consistently " perissodactyle." The 

 truly remarkable peculiarity of its skull is the tendency of the 

 outer wall of the bones to extend into ridges and bosses ; and this 

 not only in the cranium proper and upper jaw, but also in the 

 lower jaw. If these bosses were legitimately interpretable as 

 "hom-cores," we must give the animal a pair of horns descending 

 from the under and forepart of the mandible to match the pair 

 ascending from the maxilla. But the singular processes descend- 

 ing and diverging, as a pair, from the mandibular rami, show as 

 marked an absence of any indication of their having been sheathed 

 with horn as do the pairs of protuberances from the nasal, maxil- 

 lary, and the frontal bones above. 



SCIENTIFIC INTELLIGEI^ 

 I. Chemist KY and Physics. 

 1. Biplometer. — M. Landolf has invented an 

 measuring the diameter of objects without touching them and in- 

 dependently of their movements. A wedge-shaped piece of glass 

 is cut in two along a plane perpendicular to the edge of the 

 wedge, and joined togetlier again after turning one piece 1 80°. 

 Looking through the line of junction of the prisms, objects will 

 appear double, because the prisms will deviate the rays in oppo- 

 site directions. When the two images appear just in contact the 

 doubling will be just equal to the diameter of the object. Hence 

 knowing the distance we can compute the diameter, or vice versa. 

 The prisms slide over a graduated rod so that the object being 

 placed at one end they are moved until the two images are just in 

 contact, w^hen the distance furnishes a ready means of determin- 

 ing the diameter. In the instrument actually constructed a dis- 



sequently tenths of a millimeter were readUy measured. Evi- 

 dently motions of the object do not affect the measure since both 

 images move together.— Comjo^es Jiendus, Ixxxii, 424. 



[Numerous applications of this instrument will suggest them- 

 selves. In natural history the dimensions of various parts of ani- 

 mals or plants, whether large or small may be found, and in physics 

 objects which cannot be touched, as bubbles, vibrating bodies, &c., 

 may be quickly measured. By setting the prisms as an eye-glass 

 this instrument would form a convenient substitute for a telescope, 

 m measuring distances with a telemeter.] e. c. p. 



2. Specific Meat of Gases.— M. Wiedemax.v has published in 

 full his measurements of the specific heat of gases referred to m a 

 fecent number of this Journal (cviii, 465). His results are given 

 m the following table in which the first column gives the name of 

 the gas, and the second, third and fourth its specific heat under 

 constant pressure at temperatures of 0°, 100° and 200°. The last 



