104 
AMERICAN AGRICULTURIST. 
[April, 
TOYS 4 (MEW TOWMm 
The Doctor’s Talks. 
Several people, old as well as young, having asked 
about Rain Gauges (instruments for measuring the 
amount of the rainfall), we recently asked any of our 
readers having a simple Rain Gauge to send us a de¬ 
scription. A number have kindly responded. But be¬ 
fore talking about the measuring of rain I must reply to 
a young Jersey friend who goes to the very root of the 
matter by asking: 
“ Where Does the Rain ( ome From?” 
or his several queries may be all summed up in that 
form. I am always glad to have my young friends ask 
about such things, as the rain, snow, ice, the wind, and 
the like, for a knowledge of the simple facts of every¬ 
day life is of far more use than many things that young 
people are taught. This question about rain takes me 
back to the time when I knew much more than I now 
do—or thought I did. Probably a boy is never so wise, 
in his own conceit at least, as when he is near the age of 
18.—When about that age, I was honored by the friend¬ 
ship of one of the most learned men I have ever met, 
one who but for his modesty would now out-rank many 
who are regarded as eminent in science. This gentle¬ 
man wrote a work on 
“ The Mechanics of Nature,” 
one object of which was to show that all forms of 
force, or power on the earth, were to be traced to the 
sun. He kindly gave me a copy of the work, one far in 
advance of its time, and I think I learned more from it 
than any other book I ever read. Still in my youthful 
wisdom, I thought I had an exception to the statement 
that the sun was the sole source of power—and when I 
next met him suggested that 
“ Water Power was not due to the Sun.” 
He pleasantly asked me a few questions: “ What 
moves the water wheel ?"—I answered: “The force or 
fall of the stream.'’—“ What supplies the stream?”— 
Ans. “The rains, of course.”-—“ Where do the rains 
come from?’’ — Ans. "The clouds.”—“What forms the 
clouds ?”— Ans. “ The vapor in the air.”—And what pro¬ 
duces this vapor ?”— Ans. "‘The sun!”—Thus, you see, 
he made me confirm his view, and those questions and 
answers, made—oh, how long ago1—here come up, to 
answer a recent question about rain. To make the mat¬ 
ter plainer, we must recall a few things stated in former 
Talks. You know that if you place a saucer of water 
in the open air, the water will soon disappear. 
What Becomes of the Water? 
Some of you will say that “ it evaporates,” others that 
“ it dries up,” both meaning the same thing. The water 
is taken up by the air, which remains as transparent as 
before ; we can not see the water while it is mixed with 
the air, as it is an invisible vapor. Now I must ask you 
to turn to my Talk in January (page 26) where, in talk¬ 
ing about Frost and Snow, I gave the important facts 
concerning 
“The Moisture in the Air.” 
If you begin at this heading, and read carefully down 
to “Falls in the Form of Snow,”—it will save me re¬ 
peating it here. As there stated, the amount of moist¬ 
ure which the air can contain depends upon the tem¬ 
perature. For example, HiO pounds of air at the freezing 
point can hold only one pound of water as vapor, while 
in summer, when the temperature is 86°, the air can hold 
four times as much vapor, i. e. ICO pounds of air can 
hold four pounds of water or '/ 40 th of its weight. In 
January some simple methods are given to show when 
the air is moist or dry. When you have read a part of 
that “Talk” carefully, you will see that the amount of 
moisture or vapor the air can hold, 
Depends Upon tlie Temperature, 
and will understand that if the air at 86° can hold four 
times as much water as it can at 32°—if the warm air 
be suddenly cooled, it must let go, or deposit a part in 
someform, which maybe as rain. But where does the 
vapor in the air come from ? A glance at the map of the 
world will show you that about three-fourths of the sur¬ 
face of the globe is covered by water; while there are 
large lakes, inland seas and rivers, the most of the water 
is in the great oceans. By the action of the sun, the 
change of water into invisible vapor is constantly going 
on from the ocean, just as from the saucer before men¬ 
tioned, and the air becomes filled with all the vapor it 
can take up. But as shown last month, the air is by 
no means quiet. 
The Sun is Here at Work, 
and air currents and winds are moving from place to 
place, from the ocean to the land and from a warm part 
of the earth to a cooler part. It is a well known fact 
that the higher we go from the surface of the earth, the 
cooler it is. It is not so warm several thousand feet 
nearer the sun, as it is at the earth's surface, and we 
know that mountains a few thousand feet high have 
their tops in perpetual snow. One reason for this 
greater cold in the upper regions, is, that the rays of 
the sun are only partly taken up by the atmosphere, but 
fall upon and heat the earth, which in turn warms the 
air in contact with it. If you think of the matter, you 
will see that the warm and moisture-laden currents of 
air, if they go up, will be cooled; if they go inland 
and strike the high mountains, they will be chilled, 
and in the general motion of the winds these warm and 
moist currents will meet with cold currents. Being 
cooled in these several ways in the warmer air, can no 
longer hold its vapor, which must be dropped as rain. 
But Ruin Comes from Clouds. 
Before the invisible moisture comes down as rain (or 
snow) it first collects in a visible form, as fog, as we call 
it when near the earth, or as 
clouds when above us, but both, 
fog and clouds, are the same 
thing, differing only in position. 
In the formation of both, the in¬ 
visible vapor of the atmosphere 
becomes visible. It is not well 
understood in just what condi¬ 
tion the moisture is, when we 
can see it as fog, mist, or clouds; 
it has been called “ water dust,” 
and it has been supposed that 
the little particles of water are 
hollow’, like soap-bubbles, but 
this is not proved. We onlyknow 
that the moisture in the air is 
in such a state that we can see it. 
Clouds Present a Variety 
oi Form, 
to w’hich different names have 
been given. When no clouds of 
any kind are to be seen, the sky 
is said to be “ clear,” a condition 
which in our climate we are 
often glad to see. You must 
have lived, as I have, in a coun¬ 
try where there are no clouds, 
except for a month or so in 
the year, to know how beautiful they are, and how 
tiresome a constautly clear sky becomes. You know 
that at times the sky is often flecked with light clouds, 
which appear to be very high up and stretch in streaks 
of various forms across the sky. These are called Cirrus 
clouds, a word which means “ curl ” and “ curl cloud ” 
is quite as good a name as “ Mare’s-tails,” as the sailors 
call them. These are the highest of all clouds; while 
on very high mountains, one can see the other kinds of 
clouds below him, these “curl clouds” are still far above. 
It is supposed that they consist of frozen vapor, or 
minute snow flakes. In early morning, and near sunset, 
the clouds are often seen low dow n and in straight lines. 
These are called Stratus clouds (from the Latin word 
meaning “ to spread ”). The most beautiful of all clouds 
is the Summer Day Cloud, the “ Cumulus ,” as it is called 
(the same w’ord in Latin means “ a heap ”). Those great 
billowy clouds are ever changing- in outline, and on a 
summer’s day you like to watch the changes and imagine 
they are like various objects, and from them you build 
“castles in the air.” These are the three 
Principal Forms of Clouds, 
but those who study the subject make several others from 
the combinations of these, but we need not care about 
any other except the “ Rain Cloud,” or Nimbus (the Latin 
A SCENE SHOWING THE DIFFERENT KINDS OF CLOUDS. 
word for “ rain storm ”), a dark low cloud which is often 
made up from two or more of the other forms. You 
know this cloud well, if not by name, and when you see 
it you feel safe in saying: “ it is going to rain.” N 
The engraving, fig. 1, shows those different forms of 
clouds ; at the top the Cirrus , lower down the Stratus 
and Cumulus, and nearest to the earth of all is the Nim¬ 
bus or rain cloud. When the conditions are such as to 
cause the vapor in the air to be deposited, it comes down 
in drops as rain. I can now say but little 
As to the Rain Fall, 
except that it varies greatly from local causes, from some 
districts in South America, where it never rains, to other 
countries on the same continent, where it rains the 
greater part of the year. 
It is said of the Straits of 
Magellan, that “it rains 
six days in the week, and 
is very cloudy on the 
seventh.” The rainfall is 
measured by the depth of 
the water that falls on a 
level surface. If a tub or 
tank be exposed in an 
open place, where trees or 
buildings can not prevent SECT 1° N RAIN gauge. 
any rain from falling into it, and the depth of the water 
thus caught be carefully measured after each rain storm, 
it will show very fairly the amount of rain that has 
fallen, on a level, in that locality. Any contrivance for 
measuring the amount of rain that falls, 
Is Called A Rain Gauge. 
There are many such instruments, of which the tub 
just mentioned is a simple form. Some rain-gauges are 
contrived to show a much closer measurement than the 
one referred to. It will be of little use to describe the 
rain gauges intended for very accurate measurements, as 
they are only used at the government and other observa¬ 
tories, and could not be procured by my young readers. 
Instead of so large a rain-gauge as a tub, any vessel, of 
tin, sheet iron, or copper, with straight sides and a foot 
or so across the top, will allow you to make a sufficiently 
accurate measurement. 
Some Things to be Observed. 
A vessel of this kind is a very simple instrument, but 
like the more complicated ones, its value depends much 
upon the observer. It has already been said that a rain- 
gauge must be placed where it will not be sheltered by 
buildings or trees, but be put where it will receive the 
full quantity of the rain. It should be looked at every 
morning, as there is often a sudden shower in the night. 
Every morning, make sure that the vessel is empty, so 
that the record for the day may be properly kept. In 
measuring the amount of water, it is best to use inches 
and tenths—most rules have the inches divided into 
eighths and sixteenths. You can make a measure from 
a strip of wood and divide each half inch into five parts 
with sufficient accuracy by the eye, if you can get no 
rule divided into lOths to copy from. Mark your rule in 
lead-pencil, as ink will wash out. After a vessel like 
that described, in which the depth of water is measured 
with a rule, the next simplest is 
A Rain Gauge with a Float. 
An instrument of this kind is shown in section from 
adrawing sent us by “M. H. M.,” an engineer at Law¬ 
rence, Mass. The vessel is 12 inches across and the 
same in depth. A short distance below the top is a dishing 
cover which rests upon ledges upon the sides of the ves¬ 
sel and has a 2-inch hole in the middle. A float is used to 
measure the quantity of water; this may be of hollow 
metal, or of some light wood well varnished ; it has a 
stem of sheet brass, half an inch wide, and this stem 
passes through a guide, which is seen over the hole in 
the cover. The brass stem is marked in inches and 
tenths, the reading beginning at and going down the 
stem. The Zero, or starting point on the scale, may be 
brought to the exact place on the guide, by leaving a 
little water in the vessel. Of course, an inch of rain 
fall will raise the float one inch, and this will be shown 
by the figures upon the stem. 
Telegi-ajili Alphabet and 9Sca«ling- 
Amusing Mistake. 
It is singular that with all the improvements since in¬ 
troduced, almost the whole world now uses the simple 
original telegraphic alphabet, devised by Mr. Morse. 
For land lines, sounds or blows are used for dots (_) 
and dashes (-), and these arc combined to represent 
letters. For long sea or submarine lines, movements of 
a delicate mirror are used. The electric current sent 
along the wires is so broken up as to cause a bit of iron 
to strike a quick or sharp blow, or a longer one. If the 
eye sees or the ear hears a quick click it is understood 
as a dot (.). If the iron as it comes down remains the 
smallest bit of time instead of flying up instantly, it is 
