374 



SCIENTIFIC NEWS. 



The difference between the mercurial and spirit thermos 



meters exposed to the sun is nearly the same from 10 in the 



morning till 4 in the afternoon. 



The greatest The maximum of the thermometers within doors does not 



dm Mt™' ha PP en on tlie same days as that of the thermometers with- 



trays on the out. 



vithin. ayS ^ A cIoud P assin S rapidly over the sun suddenly sinks the 

 Clouds affect spirit 2° or 3°, the mercury about 1° only. When the 

 spmt most. c i OU( j nas passed t f, e ]j quid riscs as qu j c }riy-. 



Mercury m ost The motion of the mercury is most uniform. 

 uniform. „,* 



Time of great- 1 he maximum of the thermometers out of doors in the 

 est heat. shade takes place from 2 to 3: that of the thermometers in 



the sun, from 3 to 4: and that of the thermometers within 

 doors, from 6 to 7, in the afternoon. 

 Fluctuation ob- When the heat is the greatest, a kind of fluctuation and 

 agitation is observed in the mercury, and still more in the 

 spirit, which causes them to rise and fall continually. 

 Relation be- Mr. Carnot has published a memoir on the Relation that 



lances o/anv exis * s between the distances of any five points taken in space, 

 five points in followed by an essay on the Theory of Transversals. This 

 space., y ar- f orms aTt interesting appendage to the Geometry of Position 

 of the same author. In it will be found a number of use- 

 ful or at least very curious theorems ; analytical formulae 

 for resolving ail the problems respecting a quadrangular py- 

 ramid, without supposing any knowledge but that of its 

 edges. All these formula? are symmetrical, and possess a 

 degree of elegance, that will much please the geometrician. 

 Some, it is true, may stagger the hardiest calculator, and 

 much shorter solutions might be obtained by the skilful ap- 

 plication of trigonometry ; but each problem would require 

 new considerations, which do not immediately present them- 

 selves to the mind, while here every thing flows in the clear- 

 est manner from a few known principles. This work there- 

 fore is a repository, whence the geometrician may derive 

 expressions, that will facilitate the solution of very compli- 

 cated problems. To give an idea of the calculations of the 

 author, we shall quote the enunciation of one of the last 

 problems, which is as it were the summary of those that 

 precede : (i Often right lines, joining any five points taken 

 in space two by two, nine being given to find the tenth." 



The 



