602 Notices respecting Ne'w Books. 



month was 5" Fahr. This was the coldest January since 1823, 

 the lowest point of which was stated by M. Quetelet to be 11° Fahr. 

 M. Crahay noticed the thermometer at Maestricht on the same day 

 to stand at 9^ degrees below zero. 



A short jiaper was next read from Prof. Wartmann, Geneva, 

 giving an account of an atmospheric bow, which was seen on the 

 12th February 1837, in jierfectly serene weather; it exhibited all 

 the colours of the rainbow in a very distinct manner, but it did not 

 appear in a vertical position like the ordinary rainbow, but inclined 

 to the plane of the earth ; it did not partake in any degree of the 

 nature of a halo. It became visible at 5 minutes past 10 a.m., the 

 sun shining with all its brightness, and lasted till 45 minutes past 

 10 a.m. It was not accompanied by any i)arhelia, nor was there 

 any appearance of cloud till half past 11 a.m., when a few light 

 clouds were seen passing in the superior strata of the atmosphere ; 

 the afternoon was overcast without rain. 



LXXXV. Notices respecting New Books. 



Analytical Geometry : Part First, containing the Theory of the Conic 

 Sections ; Part Second, the Theory of Curves and Surfaces of the 

 Second Order. By J. R. Young, Professor of Mathematics, 

 Royal College, Belfast. 2 vols. 12mo. Souter. 



1'^HE properties of curves and surfaces of the second order, whilst 

 - they are the most interesting of all geometrical speculations, are 

 at the same time the most important in their application to physical 

 inquiry. They did not, however, originate in the wants of the phy- 

 sical inquirer ; nor, indeed, have any great number of them been 

 discovered since the time of Kepler. There are comparatively few 

 properties of these curves now known to geometers, which were not 

 either known to the ancients, or which are not merely easy deduc- 

 tions from such as were known to them. If we except the doctrine 

 of curvature, and the properties derivable from Desargue's theorem 

 upon the " involution of six points," it would be difficult to specify 

 a proposition which is not included under the statement just made. 

 At all events, if a different view should be taken of it, no one will 

 contend that the discovery of these properties, with very rare ex- 

 ceptions, was the consequence of any feeling of a want of them for 

 aiding philosophical inquiries. 



In truth, almost numberless as the properties of the conic sections 

 are, the number which the physical inquirer needs is very few ; 

 and for the most part, these are comparatively elementary and easy 

 of demonstration, either after the manner of the ancients or by the 

 geometry of coordinates. The greater portion of them in the present 

 state of science are mere objects of enlightened curiosity and analy- 

 tical or geometrical exercise. 



Were we, however, to make the wants of natural philosophy the 

 standard of utilit}% we should greatly mistake the objects of mental 

 culture, and in no case more completely than in the one before us. 



