Vol. XXrV. No. S.] 
POPULAR SCIENCE NEWS. 
]23 
this vast wastage. The valleys bordering on the 
principal water-courses are, as a rule, sufficiently 
watered to render irrigation unnecessary. This is a 
very considerable amount of land, embracing an 
area as large as the four Middle States combined, 
and Maryland thrown in. There are thousands 
of acres of other land, of the utmost fertility when 
watered, where irrigation is an absolute necessity. 
Science and absolute certainty in agriculture is 
much more nearly secured by the process of irriga- 
tion than by any other method. There is no wait- 
ing for the uncertain rain. Capital and labor are 
not risked on uncertainties. The farmer can order 
his work with the same degree of precision as does 
the mechanic or the tradesman. Working in the 
great laboratory prepared by glacial cold and lava 
heat, the sutnmcr's sun and winter's storm, he stirs 
the soil containing valuable mineral ingredients, — 
potash, ammonia, etc., — and, being wrought upon 
by the sunlight, is fed the necessary moisture in 
regular and proper proportions, so long as the crop 
demands it, from the irrigating canal. Success is 
sure and certain, and the yield is prodigious. 
The wide range of vegetable productions where 
the land is arable, — the iVuits and vegetables rang- 
ing from tropical and semi-tropical to the hardy 
varieties of the far north, — shows to how wiile 
a field in the industrial world the extending the 
amount of arable land tends. With such a network 
of flowing streams of water, irrigation should be 
made available, and that on the most economical 
plans and best known methods. Systems of dams 
and storage reservoirs to save tiie surplus in the 
wet season, and waU;rconduits of iron to avoid 
soakage, wastage, and evaporation, should be intro- 
duced. Forests would follow as a matter of course, 
and the parched, arid air would become moistened 
and made more fit for human consumption. 
The water-power of the streams must, in time, 
become utilized. The valuable minerals found in 
p.iving (|uantities in the mountain ranges will be 
reduced and refined where lound, and the manufac- 
tures of various mechanical and econoinical produc- 
tions will follow the demands of the market. 
[Original in Popular Science Kews.] 
PREMONITIONS OF AUTUMN. 
BY PROF. W. WH1T.M.\N Il.MLEY. 
In the first days of August we begin to have fore- 
bodings of prophecies of the year's decline. It is 
still full summer, and the flowers are gorgeous; 
indeed, the most splendid of the year: but they are 
the offspring of the mature season, and have a 
thoughtful, introspective look. A few golden rods 
have already put in an appearance. They are 
specimens of Snlidaao jiintca and argula. With 
them is a conspicuous species, not yet in bloom, and 
much rarer, the Solidago rigida, Linn. We have 
not yet seen any of the true asters, but the nearly 
related white-topped aster, or Sericocarpus, is 
abundant. 
The copses are beginning to be brilliant with the 
crimson pompons of the sumac. They are as at- 
tractive here as the red-berried clusters of elder 
in the White Mountain region. We are often struck 
with the regular intervals with which these masses 
of berries appear above the pinnate foliage. The 
sumacs present another indication of autumn in the 
occasional reddening of one whole leaf, a coloration 
which puts even the cardinal flower to shame. 
Other trees also show some few branches with 
the hues of September. The red maple may exhibit 
a whole branch of ruddy foliage; the elm a bough 
of gold ; the chestnut its amber tints, and the beech 
its delicate salmon color. But fruits, after all, give 
us the most intense feeling of perfected work. We 
nolo the "cool emerald" globes of the wild grape 
hanging here and there. On the hickories the great 
nuts are swelling and growing odorous. Acorns are 
assuming their varied and beautiful shapes. When 
we stroll through the corn fields, we find here and 
there between the stately shafts, a great squash or 
pumpkin waiting for the sun's transmuting Midas- 
touch. Pretty frilled caskets in the bushes contain 
the ripening nuts of the hazel. Here, too, are the 
berries of the "black alder" (Ilex), green now, but at 
Christmas-tide, scarlet, for one glad celebration. 
Lilies and irises show great pods, which are to burst 
ere long, and resow the meadows with beauty. 
Many grasses are already dry and withered. The 
cat-tails are perfected and ready for the :eslhetic. 
But it is not alone in vegetable life that we see or 
feel this advent of the autumn. The birds do not 
sing so much in their sunny homes as they did a 
month ago; some of them are only heard in the 
early morning or at twilight. It is a sad thought 
that they are ever to leave us, but 
" 'Tis always morninjj; somewhere, 
And above the awakening continents from shore to shore, 
Somewhere the birds are singing evermore." 
Often, now as we look at the sky at sunset, (and 
there is no day when we do not gaze at this ever 
novel display, which is yet as old as time), we notice 
a green tint near the horison. It is the cold, clear, 
infallible sign-manual of September. Let the sun 
glow as he tnay, he can no longer warm that color. 
Why is it we are so sad at the sign of the inevi- 
table.' Perhaps for the very reason that we cannot 
escape them. Why does the most wretched man 
cling to life.' We all love the full splendor of sum- 
mer, when we northern people have a taste— -often 
an ugly one — of the lazy existence of the tropics. 
It is not pleasant to think again so soon of anthra- 
cite, double windows, the smell of gas, the shovel- 
ling of snow, and all the hundred annoyances 
of winter. But l>ehind all these considerations 
of time, there is the deeper feeling of instability. 
Kach autumn checks off another year, and brings to 
mind more vividly even than natal anniversaries, 
that certainty which no man can escape. 
[Special Correspondence oi Popular Science yeic8.\ 
PARIS LETTER. 
The vacations are not %'ery far oft", and the scien- 
tific world — mostly composed of professors and 
lecturers — is busily engaged in the performance 
of the last duties of the season. The examinations 
for most government schools are beginning, as well 
as the competitions for many diplomas, and some 
of the last are to continue till September. We pity 
the unfortunates who are obliged to spend a warm 
summer in the labor and anxieties of competitions, 
which will provide them with a living, or oblige 
them«to work one year more and submit again to 
the trying ordeal. Examinations for admittance to 
the Kcole Kormale, to the Ecote Votytechnique, to 
the t'coU de Saint-Cyr, and to many others are 
beginning soon, and eaeh -year the number of can- 
didates grows larger, the number of the "elect" 
remaining always the $ame. In the Medical School 
and in the Paris hospitals, candidates are always 
most numerous ; recently, for two appointments 
of hospital physfcians, there were eighty candidates, 
and all of them able and highly-educated men. 
The situation of physician to a hospital is much 
sought after, not on account of the money, — they 
are paid $300 a year, — but on account of the title, 
which is useful in securing a large practice. But 
the number of applicants for the competition — a 
very difficult one, of course — is so great that many 
men do not succeed before forty years of age, and 
now when a' inan is phy&ician to a hospital and a 
fellow oC the Medical School at forty, he is among 
the lucky ones. This is a very unfortunate fact 
from one point of view, because the man who has 
begun studying medicine at nineteen or twenty, and 
who till forty has spent his life learning what others 
have done and cramming his memory with any 
amoimt of facts and theories, studied in view of a 
given examination or competition, is certainly ren- 
dered unable to think and work by himself He ii 
tired and worn out when he succeeds, and all he 
does is to perform his duties in the school or 
hospital ; he has no gusto for original work. The 
medical profession is overrun with competitors. 
The same is observed in zoology. For some eight 
or ten years many students have followed this line 
of work, but, as the professorships are limited, many 
of them can secure no appointment, and it is quiie 
a common thing for a man who is a Sc. D. and 
M. D. at the same time to be content, at the age 
of thirty or thirty-five, with an a.ssistantship of $200 
or $300 per annum. Twenty years ago, assistants 
were young men of twenty or twenty-five, who were 
studying and had obtained no diplomas yet. This 
situation is certainly very much opposed to the 
benefit of science and of scientists, because men 
of capabilities are confined too long in inferior 
situations, where they have to work in soirte unin- 
teresting manner and spend the best time of their 
mental life in unprofitable taisks. When they, in 
turn, become professors, they are tired and have no 
relish for original work^the sole manner of advanc- 
ing science. 
Before scientific men run off to the country anil 
seashore, I am sure many will secure M. Berthclols 
recent volume on La /terulution Chimiqiie : l.aroisitr. 
Some three years ago, M. Grimaux, an able chemist, 
professor in the licole rolyiechnique, published a 
very interesting book on the history of Lavoisier'?, 
life, based on numerous documents hitherto un- 
known, among which were letters and various 
writs of the "father of chemistry." But M. 
Grimaux had in view only the life-history of his 
hero, and did not study the influence exerted by the 
scientist. This is what M. Berthelot has done, and 
none was better qualified than he for the task he has 
undertaken. He is one of the masters of modern 
chemistry, and his summary of the state of chemis- 
try before Lavoisier, and of the new roads opened 
by the great discoverer, is excellent. A very inter- 
esting part of his book is that in which M. Berthe- 
lot gives an abstract of the registers in whith 
Lavoisier day by day wrote down his experiments 
and the results thereof These registers, large man- 
uscript books, are thirteen in number, and cover 
the period from 1772 to 1788. Tfaey show how 
Lavoisier performed all his experiments and Ibl- 
lowed his ideas, and are written partly by him- 
self, partly by his wife,— who was a very devoted 
assistant in his laboratory, ^and also by some other 
persons who wrote under Lavoisier's dictation. 
There are seventeen other small registers, older 
than the thirteen large ones; they are of less 
import, although they yield valuable information 
concerning the method and manner in which La- 
voisier achieved his discoveries. This work will 
certainly be translated, and many of our readers 
will be much interested in it. Lavoisier, it is well 
known, was beheaded by the French revolution the 
8th of May, 1794, in his fifty-first jear. He was one 
of the fermiersgeneraux who were so unpopular, 
although there was no hatred against him person- 
ally. As Lagrange, the great mathematician, said 
the next day, "one moment has been enough to 
cut down that head, and a hundred years will, per- 
haps, not suffice to furnish another one of the same 
worth." However, France and science have not 
lost all in Lavoisier : Wurtz, Dumas, Pasteur, — to 
