state of the Atmosphere for the Science of Meteorology . 47 



be able likewise to see from the graphic self-registering instru- 

 ments the state of the weather at every instant at all places 

 where they exist (and this is the main point of agreement of 

 both), but only long after those circumstances are past; from 

 the telegraphs we are acquainted with it instantaneously. It 

 will yet be sometime, we avow it, before we become sufficiently 

 acquainted with the laws of the transit of the states of the 

 weather, to be able to foretell with any certainty even from the 

 known state of the weather at the neighbouring places (particu- 

 larly, also, because to the class of "surrounding places" belong 

 the places above us, and the winds and temperature reigning 

 there) ; but we shall never arrive at this point except by means 

 of exhibition of simultaneous observation. When we draw a 

 series of theoretical deductions from a given distribution of 

 meteorological indications (wind, heat, pressure, &c), and 

 compare them with the subsequent distribution which is really 

 found to follow as an effect of the first, we cannot fail to pe- 

 netrate better the origin and influence of the winds, and more- 

 over the variations of temperature produced by them. 



Therefore it will be of importance to improve our graphic 

 methods of representing simultaneous observations, and either 

 by that means or by numbers to exhibit those states in a 

 tabular form. As to die graphic method, it is to be seen in 

 the articles of Mr. Birt, Report of the Meeting of the British 

 Association, 1844, 1845, &c, that there is a want of a uniform 

 method for noting three or more variations at the same time. 

 A good graphic method would have enabled Mr. Birt to com- 

 municate more in fewer pages, and to put every reader in a 

 state to try his conclusions and to extend them. 



Martins, in his annotations to the translation of Kamtz, has 

 endeavoured to exhibit more than three variations at the same 

 time; but that method, in our opinion, is not very clear. 



Since the investigation of the great November atmospheric 

 wave is probably to be continued, it is perhaps not inconsistent 

 to propose another manner of exhibiting it. We can form a 

 map of all the places where observations are made, and give 

 to each place a sign, for example («), (6), &c. ; then the posi- 

 tion of those signs in the other part of the drawing must ex- 

 press the height of the barometer at those so indicated places 

 in the following manner. Let us draw round that map a circle, 

 which we consider as the section of a vertical cylinder, in the 

 plane of which those places are situated; let us further sup- 

 pose that at the places (a) (b) the barometers are placed with 

 the lower surface of the mercury in the same plane of that 

 circular section; so will the top of the highest standing baro- 

 meter lie in a plane parallel to the first, and give a circular 



