1879.] 
AMERICAN AGRICULTURIST. 
27 
Xlie Doctor'^ Correspondence. 
Chas. L. J., Elgin, H!., wishes to know “ about dates 
which come in coarse bags with long seeds mixed in a 
sort of preserve.'’ I suppose that many boys and girls 
who have eaten dates would like to be told somethiug 
about them,and will be surprised to learn that this sweet¬ 
ish mass which they buy as a curiosity or a treat, and soon 
tire of, forms the almost sole food of many people. But 
first let me describe how it grows. The Date is the fruit 
of a Palm— 
the Date Palm 
— and when¬ 
ever you find 
the Palm 
mentioned in 
the S cr i p- 
tures, it is 
supposed that 
Fig. THE date. this is the one 
referred to. The palms are all unlike any of our trees. 
They have a tall, straight trunk—most of them never 
branch—and at the very top a crown of long fan-like 
leaves. The engraving, fig. 3, will give you the appear¬ 
ance of the 
Date-tree, 
though that 
being taken 
from a young 
tree in Flori¬ 
da. is not so 
tall as the 
full - grown 
ones. If you Fig- 2,-sectiqn of date. 
will imagine a tree like that in figure 3, about 18 
inches through, and rising a straight naked column 
about the same size all the way to 40 and even 60 feet, 
you can form an idea of the appearance of this 
MOST NOBLE AND USEFUL PALM. 
I can not recollect that I ever saw but one full-grown 
Date-tree. That was many years ago, when I was with 
a party travelling towards the City of TJres (pronounced 
Oores ), which was then the capital of the Mexican State 
of Sonora. It was a bright Sunday morning as we left 
our camp and started towards the City. After a while a 
Bpot appeared against the sky; one of our Mexicans 
pointed it out with much glee, saying, Ures! Ures 11— 
After an hour’s travel the spot against the sky grew more 
distinct, and I could make out palm leaves. Bang—bang 
—went distant cannon, and every Mexican’s hat came 
off for a minute, wlien it was replaced with, Ures 1 Ures 11 
again. Every considerable Mexican town is a military 
post, and at a certain point in the services of the church 
the soldiers discharge their guns, or the cannon, if they 
happen to have them. This palm-tree grew more and 
more distinct, at last we crossed a little stream and 
seemed very near it. We are in Ures, said the Mexi¬ 
cans. Surely enough we wore. The one story adobe 
(sun-dried brick) houses, mostly of the same color as the 
ground they stood upon, were so hidden by trees that 
we did not see them. We had not been looking down 
for a city, but up, and this one Date Palm—it must have 
been 50 feet high—was the only conspicuous thing about 
it. We had to stay in that clutter 
of mud houses for several weeks, on 
account of an accident to a member 
of our party, and the one thing that 
made the town to me, was that one 
Date-tree, and I often thought what 
a blessing that tree was to the peo¬ 
ple living there, to always give them 
SOMETHING HIGHER TO LOOK UP TO 1 
But in giving my “ traveler's yarn,” 
I am getting away from the date t tory. 
The Date Palm has its pistillate—or 
fruit-bearing flowers, and its stami- 
nate, or pollen-bearing ones, on dif¬ 
ferent trees. Both kinds of flowers 
are at first—in the bud—enclosed in a 
hard case or sheath, as shown in fig. 4; 
this bursts open and falls away when 
the flowers are ready to bloom ; the 
flowers are small and not showy, but 
in immense numbers; some are 
shown separate in the engraving. 
The cluster of fruit, when ripe, is made 
up of long strands. The dates as 
you find them in the mats give you but 
little idea of their appearance. Figure 
1 shows the fruit, perhaps a third 
less than the real size; when ripened 
on the tree they are very rich and 
pulpy. If to be sent away, they are 
picked somewhat before they are 
quite ripe and dried, and in this un¬ 
pressed condition small quantities are 
imported into New York and other 
cities, but as they are rather expensive, 
I doubt if many are sent to the inland 
towns. These appear like fig. 1, but 
larger, are of an amber-color, and 
when cut open show the seed or Date- 
stone within a cavity, as in figure 2. 
The fruit in this state is very tender, 
and without the cloying sweetness of 
THE DATES IN MATS, 
which are not, as many suppose, pre¬ 
served in sugar. They are simply the 
ripe dates crowded into bags of 
matting, by which they lose their 
shape and are pressed flat. It is in this 
form that they are put up for keeping 
and commerce. The date is abundant all through north¬ 
ern Africa, and has been taken to other countries where 
the climate is sufficiently warm to allow it to perfect its 
fruit. Some wandering tribes of the deserts live almost 
entirely upon dates, and a failure of the date crop—which 
rarely happens—is a great calamity. Nearly every part 
of the tree serves the people, whore it abounds, for some 
use. The trunk supplies timber, the leaves are made 
into baskets and bags, and even the stones or seeds 
serve as food for the camels. Date-stones usually ger¬ 
minate readily, and if you care to plant some in a pot or 
box, you can learn how the Date-tree looks when young. 
... .Thos. S. M., of Lawrence, Kas., wishes me to tell him 
ABOUT COLLODION, 
and why it is used in taking photographs. Collodion— 
from a Greek word, meaning “ to stick”—came about 
very curiously. About 30 years ago, a German chemist 
wiped up some acid with a lock of cotton, and when he 
threw it into the fire, noticed that it burned with a flash, 
and differently from common cotton. He took the hint, 
and made experiments, and found by soaking cotton 
in a mixture of nitric and sulphuric acids, washing and 
drying it, that, while it looked like ordinary cotton, it 
would explode with great force—■with more power than 
gunpowder. This was called gun-cotton, and while it is 
not much used for guns, it is sometimes employed in 
blasting. A medical student in Boston discovered that 
gun-cotton would dissolve in ether, and make a varnish 
which he called collodion; he found it dried upon his fin¬ 
gers, as a film which would not wash off, and was trans¬ 
parent. It occurred to him that this might be used for 
dressing wounds, and it is still employed in some cases, 
and still sold as liquid court plaster and liquid cuticle, to 
cover places where the skin has been knocked off, and 
for such uses. But the greatest use of collodion is in 
photography; it dries very rapidly, and forms a thin, 
transparent film. Some of the. chemical substances used 
in taking photographs are dissolved in collodion ; a little 
of this poured upon a clean plate of glass at once spreads 
evenly over the glass, the ether dries away in a few min. 
utes, and there is a transparent coating of the needed 
kind for the light to act upon, in taking the picture. Of 
course, this is a mere outline, and does not pretend to 
tell all about taking the picture—only the use of collo¬ 
dion, in doing it. See what a great thing baa come from 
a mere trifle—our portraits and views, which are often so 
dear to us, are all due to that sharp-eyed Schonbien, the 
chemist, who would not let such a trifle as the unusual 
burning of a bit of waste cotton pass, without looking 
into the cause, and following it up. At first it was 
thought that gun-cotton would supersede gunpowder, hut 
there are reasons why it is of but little use as a destruc¬ 
tive and life destroying agent, while it has found a 
more peaceful as well as more beneficent work to do. 
HARD TO GUESS—DIFFICULT QUESTIONS. 
Our young friend, “ W. J. E.,” Newark, N. J., found 
some little black things, about the size of a flax-seed, in 
a decayed squash; finding something alive within them 
he put them in a bottle ; afterwards he found a large fly 
in the bottle, and one of his little black bodies empty; 
be asks me to tell “what they were, and all about them ?” 
—It is not always an easy matter to say what an insect 
is, if I have it before me, but to give a name from no 
other description than “a large fly” is impossible. I 
mention this case, because it is of a kind that happens 
frequently, and it will explain why a number of ques¬ 
tions have not been answered. I am desirous of helping 
you learn about such things, but you must do something 
towards it yourself. When you send me an insect or 
other matter that you would know something about, you 
may be sure that I do not give it up without a trial; but 
when you simply say “ a large fly,” I give it up at once. 
Some questions are not answered because they do not 
belong to our paper at all, and especially not to the boys 
and girls part of it. For example, one boy wishes me to 
tell about Hindoo arithmetic, another how to make 
Lager Beer—and another about training trotting horses t 
To tell a Missing Figure.— Here is a little 
trick with figures, that is very puzzling until one knows 
how it is done, and after one knows it, that it should 
be so is not the less puzzling. Ask another to put 
down several figures to make a high number. Suppose 
18273615. Tell him to add these figures, which, in this 
case, will give 36. Then subtract this sum from the 
figure 18273645—36=18273609. All this while you have 
not seen the figures. Tell him to cross out one of these 
