72 
POPULAR SCIENCE HW^S. 
[May, 1891. 
industry aside from the illuminating product for 
wliich it was first undertaken. 
In addition to the four hundred or more hrilliant 
aniline, alizarine, and naphthaline colors, we also 
derive from benzol, carbolic, benzoic and salicylic 
acids, anfifebrin, antipyrin, saccharin and thymol, 
all important medicinal agents ; artificial oil of 
almonds and oil of wintergreen, the powerfully 
explosive picrates, the invaluable photographic 
developers, hydrochinone and eikonogen, besides a 
host of other substances interesting to the chemist 
only from a theoretical point of view. Quinine 
and morphine also belong to this series, but have 
not yet been artificially produced, while indigo, 
also a derivative of benzol, has already been 
prepared in the laboratory, although at a cost far 
exceeding that of the natural product. Finally 
the pasty mass left after the distillation of the 
coal tar and known as asphalt forms a most excel- 
lent material for pavements and sidewalks. 
Curiously enough the petroleum oils of America 
do not contain any of the aromatic series of hydro- 
carbons; their constituents belong to another 
series known as the parafHnes, which do not con- 
tain the benzol ring. It is said that the East 
Indian petroleums do contain the aromatic hydro- 
carbons, but the supply is very small and uncei'- 
tain, and until some chemist succeeds in artificially 
chaining the atoms of carbon together into the 
wonderful benzol ring, we must depend upon the 
by-products of the gas works for many of our most 
important and valuable medicines and chemicals. 
<♦> 
" IMPRESSIONISM"' IN PHOTOGRAPHY. 
Truthfulness to nature is abpve everything 
else a characteristic of the pictures made by the 
photographic process. A painter can suppress 
objectionable features in a landscape, or can 
"idealize" his portraits to correspond with the 
wishes of his sitters, but, aside from the limited 
aid afforded by retouching, everything within the 
range of the camera is depicted on the plate with 
uncompromising accuracy- — whether it be the 
crooked nose or strabismic eye of the sitter for a 
portrait, or the omnipresent telegraph wires and 
poles in a landscape. 
With a proper discrimination in the selection of 
subjects and the point of view, it is not difficult to 
avoid the introduction of undesirable objects, and 
the almost microscopical accuracy of a good photo- 
graph then becomes one of its chiefest charms. A 
photograph of a tree, for instance, will show the 
form of every l)ranch, twig and leaf, with a fidelity 
and wealth of detail which no artist could ever 
hope to reproduce with his brush. A fraction of 
a second suffices to imprint on the sensitive plate 
a picture which would require the work of months 
to reproduce by hand. 
Under these circumstances it is exasperating to 
note the rise of a class of so-called "impressionist" 
photographers who claim that an absolutely sharp 
focus and rectilinear lines are objectionable in a 
truly "artistic" photograph. One of these cranks 
recently published an article in a photographic 
journal, claiming that a lens should not be too 
perfect, but was all the better for a certain 
amount of astigmatism and imperfect definition, 
on account of its imitating the natural imperfec- 
tions of the human eye, and producing a picture 
"just as one sees it." To take the illustration of 
the tree again, these deluded persons claim that 
when we look at a tree we do not see every leaf 
with perfect distinctness, and therefore the pic- 
ture of that tree should l)e made a little fuzzy, or 
"soft," as their term is, to correspond. Xotlung 
could be more erroneous. When we look at a tree 
as a whole we do not see every leaf distinctly at 
the same time, because in an immobile ej'e the 
field of distinct vision is extremely limited ; but 
the eye is not immobile, but in constant motion, 
and as we look successively at every part of the 
tree, every part of it is seen with perfect distinct- 
ness, and every leaf and twig impresses itself 
upon the retina in its natural form. The case of 
the photograph is identical — as the eye passes over 
the different parts of the picture it should see all 
the details as distinctly as in looking at the ob- 
ject itself, and a blurred, distorted " f uzzytype " 
is not a correct representation of anything on 
earth as seen by the human eye, unless, indeed, 
said eye is in urgent need of a pair of spectacles 
or a surgical operation. 
When we see an oil or water color painting, ap- 
parently executed w ith a whitewash brush, a steam 
atomizer, and a squirt gun, described as a wonder- 
ful work of art denoting extraordinary genius on 
the part of the artist, we are willing to allow the 
critics all the pleasure they can obtain from it, but 
we, nevertheless, hold to a private opinion that it 
simply denotes mere affectation or, more likely, 
lack of ability on the part of the artist to produce 
anything better; and when we see a distorted, 
badly focussed photograph \ipheld as an example 
of the " impressionist " school of art, a very strong 
suspicion arises that the admired result is really 
due to the combination of a five dollar outfit, and 
an inability on the part of the alleged photo- 
grapher to properly focus his pictures. If anyone 
desires an astigmatic lens they can easily be pur- 
chased at extremely moderate prices, but our ad- 
vice to the amateur photographer would be to 
prociire the best lens that he can afibrd, focus 
down to the greatest possible sharpness, and then 
in addition use the Smallest stop that the circum- 
stance will admit of. There are no " hard " lines 
in nature, and it is useless and presumptuous to 
attempt to improve upon them by intentional dis- 
tortion, or by a blurred and indistinct image which 
no normal human eye has ever yet formed upon 
its retina. 
[Original In Popiilaii Science News.] 
EARTH-STARS. 
BY FRED'K LEROY SARGENT. 
Among the many odd plants which have become 
adapted to live under the trying conditions im- 
posed by arid and sandy localities, few are more 
curious than certain species of the genus Geaster, 
which are common in dry places throughout the 
greater part of North America, Europe, and Asia. 
The name of the genus is derived from the Greek 
gc, earth, and asti'r, a star, and is thus a transla- 
tion of the popular name, " earth-star," which 
was applied to these plants from their form when 
expanded on the earth, as shown in Fig. 2. 
Since the earth-stars are leafless and destitute 
of chlorophyl (the green coloring matter of foli- 
age), they belong to the great group of Fungi, 
which includes mushrooms, puff'-balls, moulds, 
and innumerable microscopic sorts. We know 
that all plants from which chlorophyl is absent 
nuist depend for their nutriment upon a supply of 
organic material, and it is therefore something of 
a puzzle at first sight to know how the sand- 
loving earth-stars can obtain such food in the 
localities they frequent. What we see above 
ground, however, is not the whole of the plant, 
but only the fruit, which is developed from a mass 
of delicate subterranean fibers constituting the 
planfs vegetative apparatus. By carefully scrap- 
ing away the earth at the base of a young Geaster, 
these fine white threads, or hyphai, may be discov- 
ered ramifying in all directions. A few species 
of Geaster grow in rich, moist woods, and with 
these it is easy to understand how the hypha) can 
obtain an abundance of organic food from the 
surrounding leaf-mould or decaying wood. In the 
case of the sand-loving forms we must assume 
that decaying pieces of roots from neighl)oring 
grass plants and shrubs, along with the remains 
of dead leaves and animal debris which become 
bm-ied in the sand, supply all the food necessary. 
It takes a considerable time, however, for the sub- 
terranean hyphae to obtain a sufficient store of 
nutriment to build the elaborate fruit; and, al- 
though the hyphai are at work all the spring and 
summer, or perhaps even longer, it is August or 
later before anything is seen of them at the sur- 
face of the ground. 
Fig. 1. 
The first sign of the fruit is an egg-shaped 
nodule of compacted hypha;. In a comparatively 
short time this enlarges to the size of a robin's 
egg or larger, and then is developed a thick outer 
wall enclosing rather soft contents. In the sub- 
sequent process of ripening, the pulpy interior 
becomes almost entirely transformed into an im- 
mense number of exceedingly minute liodies, 
known as spores, each of which — under proper 
conditions — may give rise to a new plant like the 
parent. An average size earth-star is estimated 
to contain about 10,000,000,000 of these spores, 
which are, of course, so excessively tiny that a 
powerful microscope is necessary to see a single 
one of them by itself. When viewed in the mass 
they appear as a brown impalpable powder which 
a breath of air will blow away. In the way their 
spores arise within a closed cavity, the earth-stars 
are quite like their nearest allies, the puff-balls, 
and differ from the mushrooms, whose spores arc 
developed on the surface of external gill-likc 
membranes, or projections. Such internal spore 
formation places the earth-stars in the order 
Gasteromycetes (Greek gaster, belly, and myketos, a 
mushroom), which includes besides the puff-balls 
the repulsive "stink-horns," the "btrd's-nest 
fungi," and a number of others less commonly 
known. 
.*»^_ 
' j'^'' 
Fig. 2. 
The essential difference between the earth-stars 
and the true puff-balls is in regard to the wall, or 
rind, of the ripe fruit. In the puff-balls this riud 
is comparatively thiu, and consists of an outer 
and an inner layer, which remain permanently 
united. The rind of the earth-stars comprises 
likewise an outer and an inner division, but the 
former — which is comparatively thick — splits into 
segments, and these ultimately separate from tlie 
delicate inner rind, exposing what looks like a 
little puff-ball. At the top of this may now be 
seen a small opening through which the spores 
escape. The spreading apart of the segments is 
