20 
■POPULAR SCIENCE NEWS. 
[FiBRUARY, 1890. 
July, twenty-onfe days during August, and eleven 
days during September. There were three heavy 
rains in June, six in July, six in August, and one in 
September. During the June part of the rainy 
season there was a rainfall of 10.23 inches; in July 
the rainfall was 9 41 inches, in August it was 11.30 
inches, and in September (to the end of the rainy 
season) it was 6 02 inches. The total precipitation 
during the rainy season was 36 96 inches. 
The rains of this season are sometimes produced, 
as rains ordinarily are, from clouds that have slowly 
formed ; but the typical rainy season shower comes 
with little warning from an almost cloudless sky, is 
of short duration, and is followed very soon by a 
clear sky again. During some rainy seasons there 
is a great deal of thunder and lightning, while there 
is very little during others. The season of this year 
was one of many thunder-storms, the accompanying 
lightning being often very vivid and abundant, 
while last year's rainy season had but few thunder- 
storms. 
The cause of this season of abundant rains may 
be learned from a study of the nature and direction 
of the winds that prevail in this region during the 
summer months. The United States (except 
Alaska) extends through two wind zones, the 
variable and the sub-tropical zones, and Florida 
lies in the sub-tropical zone. In this zone the 
easterly trade winds prevail in the western part of 
the United States, but in the eastern part the trades 
are 'frequently interrupted by monsoons from the 
Gulf of Mexico. These monsoons, warmed by the 
Gulf Stream, — on account of which the temperature 
of the western coast of Florida is several degrees 
warmer than that of the eastern coast in the same 
latitude, — and heavily charged with moisture, meet 
the colder trades in this region, and to this occur- 
rence the rains of our rainy season are largely due 
The rainy season, occurring as it does during the 
hottest months of the year, is of immense benefit to 
the climate and vegetation of Florida. If excessive 
exposure to the direct rays of the sun can be 
avoided, a Florida summer, with its almost constant 
breezes, and cool nights, is much more tolerable 
than the summer weather of many regions of the 
North, especially those not in the vicinity of moun- 
tains. Vegetation is very luxuriant during this 
season, — indeed, the rainy season is the great plant- 
growing season of Florida, for two important con- 
ditions of plant growth, heat and moisture, are then 
abundantly supplied. It is during this season that 
citrus trees — and hence, also, their fruit — make their 
most vigorous growth. If our long summers were 
dry, and our winters were wet, living in Florida 
would be far less desirable than it is, — for our win- 
ter climate, as well as that of our summer, would 
siilTer thereby, — and the products of the soil would 
be of far less value than they are. Indeed, if this 
were the case, the citrus fruits might not be success- 
fully produced in Florida. The Florida orange 
would certainly not be the superior fruit that it is. 
An interesting matter connected with heavy rain- 
falls in Florida, is the readiness with which the soil 
in most places receives the water. It might be sup- 
posed that an average of three inches of rain a week 
for twelve successive weeks, — the average during 
our last rainy season, — would iill the soil beyond its 
capacity for holding water, and that much of the 
rain-water would flow off. But this is not the case; 
most of this large amount of water, which, were it 
to fall on clayey soils, would produce damaging 
floods, quietly sinks into the sand, and is lost to 
sight. Only when rain falls rapidly and in large 
quantities, are surface streams formed, and these 
soon disappear. The surface soil of central and 
southern Florida is composed of sand and vegetable 
mould, and this stratum is succeeded by almost 
pure sand, extending to the depth of several feet, 
and underlying this there is usually a stratum of 
clayey sand, called "hard pan." Sand follows this, 
and a second layer of hard pan is usually met before 
selid rock is reached. 
Although winter is called the dry season of Flor- 
ida, it is not to be understood that it is always its 
dryest season, as there is often less rain during the 
spring and autumn months than during the winter. 
The rainfall during March, April, and May of this 
year was i 77, 2.45, and 2 08 inches for the respec- 
tive months, and that for October and November 
was only i 84 inches, while last winter was quite 
wet, the rainfall during January and February alone 
being 15.08 inches. These facts lead to the conclu- 
sion that Florida really has no dry season. It 
would be more correct to classify her seasons, so 
far as precipitation is concerned, as the rainy season, 
and the season of irregular rains. 
Orlando, Fla., Dec. 13, 1889. 
Practical Clioiiiistry aijd tlje yirts. 
NOVELTIES IN PHOTOGRAPHY. 
The applications of instantaneou.s photog- 
raphy are constantly increasing with the 
greater sensitiveness of modern plates, and 
SCIENTIFIC BREVITIES. 
Hot Water Plants. — ^J. Walter Fewkes has an 
interesting paper in the May number of the Ameri- 
ean Naiuralist on the vegetation of hot springs. 
That vegetation can exist in these hot springs — the 
highest temperature on record in which it occurs is 
200° Fahr. — indicates that vegetation may have 
occurred at a much earlier stage of the earth's his- 
tory than has been generally supposed. The pre- 
vailing form of vegetation in these heated waters is 
algae. Diatoms also occur, but sparingly. They 
have been found in Nevada at a temperature at 
which the vegetation of hot springs is most flourish- 
ing, but usually occur in great abundance in the 
cooled waters of hot springs. 
Combined Fresh Water, Brine, and Gas 
Well. — One of the most remarkable things of 
which Pittsburg boasts is the combination well that 
has been struck on Liberty street. It produces at 
one and the s«me time cold water, pure and sweet; 
salt water, and a flow of gas that, when ignited, 
illuminates the entire surroundings. The well was 
drilled some time ago, to get a supply of pure cold 
water for use in a bakery in the summer and during 
flood times, when city water is not desirable. At 
100 feet the fresh water was struck, and at 200 feet 
the salt water and gas were found. Two casings 
were inserted, — one for the salt water and gas, the 
other for the fresh water, — and now, when the 
engine is started and the gas lighted, spectators 
behold the wonderful sight of fresh water, salt 
water, and fire all coming out of one well at the 
same time. 
Twenty Years of Science. — The editors of 
Nature (London), on the occasion of the twentieth 
anniversary of the establishment of the magazine, 
take occasion to review the progress of science dur- 
ing that period of years. In the physical sciences, 
the development of the atomic theory and the estab- 
lishment of a connection between the theories of 
electricity and light, have been the main achieve- 
ments ; in chemistry, the proclamation of the peri- 
odic law of the elements and the development of 
organic chemistry ; in astronomy, the development of 
the spectroscope, the use of photography, und the 
extension of the nebular hypothesis ; in biology, 
the firm establishment of the Darwinian docrine, 
the development ot the study of bacteria, and, later, 
the effort to determine the position of the Lamarck- 
ian principle, have been the main features. In 
botany, the key-note has been the study of proto- 
plasm and cell-life ; in geology, the greatest advance 
has been in the application of the microscope and 
the stxidy of rock structure. 
Fig. 1. 
the more powerful developers which are 
being almost daily discovered. Apparently, 
there is no limit to the brevity of the time in 
which the sensitive gelatine film may receive 
arid retain a luminous impression, and photo- 
graphs have been taken in such a minute 
fraction of a second, (0.000076), that the ele- 
ment of time is not worth cosideration, and 
they may be considered as absolutely " instan- 
taneous" pictures. 
Fig. 1. 
In Fig. I an instantaneous view of an erup- 
tion in the crater of Vesuvius is shown. It is 
necessaril}' somewhat obscured by the clouds 
