1876,] -^tld [Blasius. 



Laws." It will be seen from this article that I observed the fact as to the 

 motion of cirrus clouds besides otliers of a like nature about a quarter of a 

 century ago, lectured on it publicly and published it. Copies of the 

 article were sent to Prof. Henry and Lieutenant Maury in Washington. 

 This article which was a sketchy summary of my investigations, contains 

 also the laws of the motions of the lower cloudforms, such as cumulus, 

 cumulo-stratus, conus. And it contains not only the laws as to the direc- 

 tion the different cloudforms take, but also an explanation of the causes of 

 their motion, and tlie application to the prediction of storms. I mention 

 these facts to show tlie overpowering influence of recognized autliority in 

 accelerating or retarding the development of a Science. Truth of the 

 greatest importance often remains unnoticed if it does not pass first from 

 the lips of a well-known authority, and errors may be propagated for 

 centuries under the shadow of a great name. Although late, it is gratify- 

 ing, however, to see my observations confirmed as the heavy train of 

 Science moves onward. 



Another reason why ray observations have remained unnoticed so long, 

 may also be found in the circumstance that I have seen and described 

 meteorological phenomena from a difterent standpoint from that generally 

 taken. A circular ring will appear to one as a straight line, to another as 

 an ellipse, and to a third one as that wliat it really is, according to the 

 standpoint from which it is viewed. This is very apparent in looking at 

 phenomena the whole of which we cannot see at once, such as the motions 

 of heavenly bodies or storms ; we then are likely to take things as they 

 appear to be. So men thought for centuries that the sun moves and the 

 earth stands still, and the cyclonists think even now that the wind in a 

 storm moves around in a circle, or in an ellipse, or in a spiral, because it 

 appears so. They see in the "area of low barometer" the whole storm, 

 while I from my standpoint see in it only the effect of the storm. The 

 cyclonists see in the areas of loic and MgJi barometer independent although 

 unexplained phenomena ; to me these phenomena appear to belong to- 

 gether as organic parts of the storm and assume thus a meaning. With 

 me a progressive storm consists in the displacement of one of two opposing 

 air currents by the other, which is of different temperature, and the area of 

 low barometer forms itself during this conflict between them by the rising of 

 the warmer current obliquely over the colder one. The rising air produces 

 lower pressure, but the full weight of each current produces tlie areas of 

 high barometer in front, and in the rear of the area of low barometer. I, 

 therefore, see the storm extend over much larger area than the cyclon- 

 ists do. 



I see in the ferial currents the elements of the storm, the cj^clonists seem 

 to consider them as the consequence of the storm. I, therefore, naturally 

 consider the motion of the difierent cloudforms in reference to the serial 

 currents, and not in reference to barometric pressure, but the facts of their 

 motion are and remain the same. 



The "cirro stratus " of Howard — in fact all cirrus clouds — move with the 



