4 E. Loomis — L'oiitsihntioxx t<» Meteorology. 



ber of rain areas at which the rain-fall since the preceding 

 observation amounted to at least one-half inch ; column thir- 

 teenth shows the velocity (in miles per hour), and also the direc- 

 tion, of the highest wind reported at any of the stations which 

 could be regarded as included within the influence of the low 

 barometer traced in columns sixth and seventh. Occasionally 

 it happened that the same velocity was reported at several dif- 

 ferent stations. In such cases the direction of the wind is 

 given for each of these stations. 



For each of the cases named in this table, the curves of one- 

 half inch rain-fall, and also of one inch rain-fall have been 

 carefully drawn upon the Signal Service maps. These curves 

 show the form and magnitude of the rain-areas and their posi- 

 tion with reference to the center of low pressure. The cen- 

 tral portion of two of these maps is exhibited on Plate II. 

 The character of these results cannot be fully exhibited with- 

 out the publication of the entire series of maps ; but since 

 such a course is i in practicable, I have adopted the following 

 artifice. I took a sheet of transparent paper, and ruled upon 

 it two lines at right angles to each other ; one line representing 

 a meridian and the other a parallel of latitude; the point of 

 intersection of these lines being designed to represent a center 

 of low pressure. Beginning with the first date in the table, I 

 marked upon the Signal Service map the center of low pres- 

 sure for that date, and also the center of low pressure for the 

 last preceding date of observation. The point mid -way be- 

 tween these two centers was regarded as the position of the 

 low center for the middle of the period to which the reported 

 rain-fall corresponded. Placing the certter of the sheet of 

 transparent paper over this point of the Signal Service map, I 

 ked up< H iper i position ot each of the rain cent i - 

 for the given date. The rain area in which the fall was 

 greatest was indicated by a small circle; the other rain-areas 

 for the same date were indicated by a cross. In like manner,, 

 the position of the rain-areas for each of the dates in the tabic. 

 was indicated. The results are given upon a reduced scale on 

 Plate I. For convenience of comparison, four large circles are 

 drawn with radii of 250, 500, 750 and 1000 miles from the low 

 center, and a few of the rain centers have numbers attached to 

 them corresponding to the numbers in the table on page 2. 

 Rain-areas distant more than 1000 miles from the low center 

 are not represented on this plate. 



One of the most noticeable facts connected with tl 

 rain storms is the large number of rain-centers 

 simultaneously, and often quite distinct from each other. 

 Plate II, accompanying my seventh paper, shows c. 



