hd, 
276 
becomes by this discovery the oldest living type of 
vertebrata. CoPE. 
Philadelphia, Feb. 28. 
Artificial production of rain. 
I give below an instance which came under my 
own observation, of the artificial production of rain, 
which may be interesting, read in connection with 
the article in Science, No. 55. 
Many years ago, during my residence in Virginia, 
the whole of the eastern portion of that state had been 
suffering one summer from a long-continued drought. 
For several months not enough rain had fallen at any 
one time to moisten the ground to the depth of half 
aninch. The atmosphere was gray, and full of-dust. 
The sun, even at noonday, was ‘ shorn of his beams,’ 
and could be looked at directly without paining the 
eyes. ‘The temperature was not unusually high; but 
the weather was very oppressive, being what is called 
in the country, ‘muggy.’ One of my neighbors had 
several months before cut down, and left lying where 
it fell, a young forest of scrub pines from a field 
of about forty acres in extent. These pines had, of 
course, become, during the long drought, completely 
dry. One August morning, the meteorological con- 
ditions remaining exactly as they had been for months 
before, my neighbor caused fire to be set to this clear- 
ing at several points on the circumference at the 
same time. The fire ran over the whole tract with 
wonderful rapidity. An immense column of inky 
smoke rose perpendicularly (there was no wind) to a 
great height. Upon reaching a stratum of air of its 
own density, the black column spread out horizon- 
tally into the form of a gigantic mushroom, rapidly 
changed color from jet black to gray, and soon thun- 
der was heard in the top of the ascending and spread- 
ingcolumn. The fuel was gradually consumed, and 
the smoke ceased; but the cloud continued to spread, 
and rain began to fall in a little more than an hour 
from the time the clearing was fired. 
The thunder gradually ceased; but rain continued 
to fall until sunset, when the sky cleared. For the 
remainder of the season, showers and rain-storms 
occurred with ordinary frequency, as if the conditions 
favorable to the continuance of the drought had been 
permanently broken up. Observations of temper- 
ature, the dew-point, and of the barometer, would 
have been valuable; but I had unfortunately no in- 
struments at hand for obtaining them. 
While the artificial production of rain can have no 
economical importance, — depending, as it necessarily 
must, upon many meteorological conditions, which, to 
be effectual, must be synchronous, — yet an example 
of a rainfall of several hours’ duration, which was 
undoubtedly produced by an ascending column of 
ee air artificially supplied, seems worthy of rec- 
ord. 
Annual growth of the ‘Tree of heaven.’ 
I have in the cabinet of Cumberland university two 
remarkable shoots of Ailanthus glandulosus, Desf., a 
description of which may be of interest to botanists. 
They grew in a lot near one of the university build- 
ings during the summer of 1883. They sprang from 
small stumps, and are entirely the growth of one sea- 
son. They give the following measurements: — 
No. 1. — Length, 10 feet 6 inches; circumference 
at base, 5.1 inches; circumference at middle, 4.13 
inches. 
No. 2. — Length, 11 feet 1.5 inches; circumference at 
base, 4.1 inches; circumference at middle, 3 inches. 
J. 1. D. HInDs. 
Lebanon, Tenn. 
SCIENCE. 
’ an active and intelligent boy. 
[Von. IIL, No. 57. 
GOUVERNEUR KEMBLE WARREN. 
In the death of Gen. Gouverneur Kemble 
Warren of the Corps of engineers, U.S. Army, 
the country has lost not only one of the ablest 
military leaders developed by the civil war, 
but also a scientific man of high attainments, — 
whose life was devoted to profound investi- 
gations connected with several of the most 
important works of internal improvement un- 
dertaken by the general government. 
He was born on Jan. “8, 1830, at the little 
village of Cold Spring, upon the Hudson, where 
his surroundings were all calculated to excite 
a love for the military service in the mind of 
West Point lay 
in plain sight from his home. The old field- 
works of the revolution, grass grown and 
crumbling, were associated with his earliest 
recollections; and the charm thrown by 
Washington Irving over this classic ground of 
American history entered into and stimulated 
his youthful imagination to ideas above the 
_ prosaic monotony of every-day life in the nine- 
teenth century. The Mexican war added fuel 
to the flame ; and at the early age of sixteen 
he sought and obtained an appointment as 
cadet at the Militar y academy. He was grad- 
uated in 1850 with very high class rank, and 
was at once assigned to the corps of topo- 
graphical engineers. 
The great problem then beginning to attract 
attention was the Pacific railroad. The recent 
discovery of gold in California, and the con- 
sequent rush of immigration to the west, de- 
manded increased facilities for transit across 
the continent; but a broad belt of wilderness, 
intersected by lofty ranges of mountains, and 
almost unknown, barred the way. It was in 
this field that the young officer did his first im- 
portant scientific work. 
Congress made large appropriations for ex- 
ploring several routes between the Mississippi 
River and the Pacific Ocean; and the work, 
under the direction of Gen.- (then Capt.) 
Wumphreys, was performed by officers of U.S. 
engineers. As usual in such cases, the results 
were expected at once; and Lieut. Warren, 
who had already shown his ability on the sur- 
veys of the Mississippi delta, was detailed as 
principal assistant in the general office at 
Washington. 
His duties were twofold. He assisted Capt. 
Humphreys, then laboring under great pressure, 
in digesting the preliminary reports, in inves- — 
tigating the various problems connected with — 
railroad transportation, in making the com- 
parative estimates of cost, and in preparing 
