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O86: SCIENCE. 
forced and diminished by the progression of the 
storm. But on lands in the temperate zone 
these terms have had little application ; for there 
cyclones proper are seldom destructive, and, 
as a general thing, do less harm by their winds 
than they do good by their rains. There will, 
however, soon be need, at least in our western 
and southern states, of a corresponding expres- 
sion, such as the ‘ dangerous octant,’ to denote 
the sector between south and east of the broad 
storm where local tornadoes may be developed ; 
for the surmise that tornadoes were thus defi- 
nitely related to cyclones, suggested by the 
signal-service studies of a year or two ago, is 
rapidly becoming a well-proved fact by the in- 
vestigations of this season. It is the most 
interesting discovery in meteorology that has 
been made of late years, in its theoretical as 
well as in its practical bearings. 
LETTERS TO THE EDITOR. 
x*, Correspondents are requested to be as brief as possible, 
The writer’s name is in all cases required as proof of good faith. 
Radiant heat. 
In his letter to Science of the 15th of February, 
Professor Eddy states, that, in his opinion, the direc- 
tion of the rays entering the region B is immaterial. 
As Iam sure no other American or other scientific 
man agrees with him, I do not think it worth while, 
now that the issue has been reduced to this question, 
for me to continue a correspondence of the kind across 
the Atlantic, especially as Professor Eddy’s mistakes 
have already been pointed out by Professor De Volson 
Wood. 
As I am writing, I may, however, as well point out 
Professor Eddy’s mistake in the arrangement he pro- 
poses as a substitute for mine. I agree that fig. 1 
and fig. 2 represent what would happen; but fig. 5 
does not represent all that would happen, as evidently, 
if heat can go into B in the direction y’z, as in 
fig. 2, there would be an escape of heat from 6 in 
the direction zy’, as well as that in the direction 
zy represented in fig. 3; and so, to the two quanti- 
ties of heat coming into B in fig. 2, there would es- 
cape two equal quantities, which should have both 
been represented on fig. 8; and then, evidently, B is 
no better off than before. 
Professor Eddy, I hope, will recollect that a pencil 
of rays of infinitesimal angle can only contain an in- 
finitesimal quantity of heat. I make the remark be- 
cause an omission to notice this fact is the only 
excuse I can see for the curious remark in the penul- 
timate paragraph of his letter. 
GEO. FRAS. FITZGERALD. 
Trinity college, Dublin. 
Another ‘yellow day’ 
On the afternoon of May 2 a strong wind from 
the south-west brought to our position (seven miles 
due west of West Point) thick clouds of smoke from = 
the forest-fires in Pennsylvania and northern New 
Jersey. At 4.15 p.m. the sun had become completely 
obscured, and occasionally cinders and bits of charred 
leaves were borne past by the wind. ‘The increasing 
density of the smoke was accompanied by a strange 
brassy, yellow light, which grew more vivid as the 
sun disappeared, and was most brilliant from five to 
six o’clock. It pervaded the whole sky with a dif- 
fused brassy glow, which was reflected into interiors 
so that an object placed before a window cast a per- 
ceptible shadow, yet the actual amount of light was 
less than in ordinary foggy or cloudy weather. The 
flame of,a student-lamp had a white, dazzling appear- 
ance, not unlike the electric light. The green color 
of grass and foliage became of a most vivid quality, 
and the various shades of red seemed unusually prom- 
inent. This was attended by a high wind of from 
thirty to forty miles per hour, the highest temperature 
of the season, falling barometer, and a remarkably 
low percentage of relative humidity, as the following 
records show in part :— : 
Hour. Temperature. Relative humidity. 
AIM.) oS rae eee 81.0° 44% 
De ee” SS eae ee eee 82.0 38 
Op) Reid Gh 1g Oe. 81.5 33 
AS 9 a a en ener 81.0 22 
Og Soh Oia peels eee 80.0 15 
CMMs amn Ee: Ber orts yor) 0 67.0 42 
Ties" Lave kate ae 61.0 45 
| 
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The noteworthy feature of the phenomenon was its 
similarity to that of the well-remembered ‘ yellow 
day,’ Sept. 6, 1881, the explanation of which was the 
subject of so much discussion. But, since the cause 
of the later occurrence was so unmistakably the 
presence of smoke in the air, persons who witnessed 
both can have little doubt that the same cause 
operated in the former case. 
WINTHROP E. STONE. 
Houghton Farm, Orange co., N.Y. 
Cretaceous phosphates in Alabama. 
Isend you by mail some specimens of phosphatic 
nodules recently discovered in Perry county, in this 
state. Their true character was first suspected by 
Mr. William Spencer, on whose land they are found 
in abundance. Specimens were sent by him to Dr. 
C. U. Shepard, jun., of Charleston, §.C., and to my- 
self, for examination, with the result of showing 
that they were nearly pure phosphate of lime. The 
geological position of this occurrence is different 
from that of the South-Carolina phosphates, as they 
are found at the base of the cretaceous rotten lime- 
stone; but the mode of occurrence is quite similar, 
as may be seen below. : 
A section (descending) of the strata at Hamburg, 
in Perry county, is about as follows :— 
1. Rotten limestone, only the lowermost beds of 
which are here present. 
2. Greensand beds from one to four or five feet in 
thickness. ‘These beds appear to be impregnated 
with phosphoric acid; analyses of several specimens, 
selected from different spots, showing an average of 
about twenty per cent. 
3. Sandy, calcareous beds about six feet in thick- 
ness. Where these beds outcrop in the fields, the 
surface of the ground is covered with nodules simi- 
lar to the specimens sent herewith. These nodules — 
[Vou. IIL, No. 67. 
