Blnslus.] -^O-t fpgb. 18, 



Avarni equatorial current, because tliey are originated by it as it ascends 

 into colder regions obliquely over the colder polar current. The "cirro- 

 stratus" I described in the Times article in 1852 as the embodiment of a 

 fully developed north-east storm, because I found it characteristic by my 

 observations of an approaching equatorial, warm current. I, therefore, 

 consider it an elementary form, and proposed the single name "stratus," 

 used by Howard hitherto for ground fog, which I consider of no form. The 

 name "stratus" admirably indicates the stretched-out, straight-line cloud ; 

 it rein-esents with my two other elementary forms — cumulus, conus — 

 geometrical forms and is therefore easily described. The other forms of 

 cirrus, commonly known as mare's tails, cat's tails, etc., are mere modifi- 

 cations of the stratus (cirro-stratus of Howard) forming during the first 

 irregular attempts of the rising warm current before it has assumed its reg- 

 ular lateral motion in which the cirrus forms assume that of the stratus at 

 the top of the regular front waves. We therefore see "the cirrus clouds 

 flow out from areas of low barometer" (the place of the obliquely rising 

 warm current) "and m toward areas of high pressure" (the colder polar 

 current). My article twenty-four years ago, therefore, tells not only the 

 facts about the motion of cirrus cloud which Hildebrandsson, Ley and Abbe 

 have recently observed, but also the cause. Besides this it contains the 

 practical application to predict from the appearance of these clouds above 

 the southern horizon the coming of the equatorial current, or the approach 

 of a north-east storm. While thus from the standpoint of the cyclonists 

 the cause of the empirical fact cannot be explained, it follows as a natural 

 consequence when seen from the standpoint I have taken. 



The article in question contains also the laws of the motion of lower 

 cloudforms, such as the cumulus, cumulo-stratus, and conus, and why they 

 take their respective course, and how the movement and condition of the 

 currents of which they are characteristic, i. e., the storm may be predicted 

 bj' their appearance. The study of cloudforms in connection with arial 

 currents is one of the most important duties ot practical meteorology. 



As to Clement Ley's proposition, "that the vertical axis of a supposed 

 revolving column of air is not exactly vertical, but inclined backwards, " 

 I would call your attention to a third opinion held by some most eminent 

 meteorologists, such as Dove, Reid and Redfield, that the axis is inclined 

 forward. The cyclonists run here again into a fresh contradiction, and 

 create a new puzzle, some saj'ing the axis lies forward, some it lies back- 

 ward, and others it is vertical. It reminds us of Redfield and Espy's dis- 

 cussions, where one maintained that the wind in a tornado moves around 

 in a circle, the other that it blows in straight lines toward the centre. 

 These discrepancies are a consecpu'nce of the mode of investigaticm univer- 

 sally followed in this science, which is to deduce results from a conglomer- 

 ate mass of disconnected data, obtained indiscriminately from storms that 

 may difl!'er as widely in origin and character as a bat and a sparrow. What 

 have we gained towards an individual knowledge of either the bat or the 

 sparrow by eliminating from a number of data the mean velocity and the 



