526 
A process which has been the means of throwing much 
light on problems in vegetable physiology and agricultural 
chemistry, namely, a comparison of the analyses of a 
plant and of its separate members in different stages of 
growth, has been applied to fifteen familiar species of 
grasses, and the results are tabulated and briefly dis- 
cussed. 
Many useful suggestions, some of them of the highest 
practical importance, are to be met with in these pages. 
Here is one by Prof. Asa Gray which refers to the 
Teosinte, or Guatemala grass, Luchlena lurxurians, a 
native of Mexico and Central America, and has the true 
ring of progress about it :— 
“To make the 7vosimf¢e a most useful plant in Texas 
and along our whole south-western border the one thing 
needful is to develop early-flowering varieties, so as to get 
seed before frost. And this could be done without doubt 
if some one in Texas or Florida would set about it. 
‘What it has taken ages to do in the case of Indian corn, 
in an unconscious way, might be mainly done in a 
human lifetime by rightly directed care and vigorous 
selection.” 
This volume is highly creditable to its authors, and it 
adds one more to the many useful publications which 
have emanated from the United States Department of 
Agriculture. W. FREAM 
THE DEVELOPMENT OF THE CCILIANS 
tes a letter recently published in the Avbetten aus den 
zoologisch-sootomischen Institut in Wurzburg, 
Messrs. P. B. and C. F. Sarasin give a preliminary 
account of the development of Zficrium glutinosum as 
observed at Peraderinia in Ceylon, where these naturalists 
have taken up their quarters near the celebrated Botanical 
Gardens. Since the original discovery by Johannes 
Miiller of the larval form of the Czcilians, almost the 
only information obtained on this important subject is a 
short account of the gilled larve of Cectlia compressi- 
cauda by Peters, founded on specimens procured by 
Jelski in Cayenne. 
The brothers Sarasin show that Epzcréum is not vivi- 
parous, as is Cecilia, but oviparous. In the most 
advanced stage before hatching the embryo is provided 
with very long blood-red external gill-filaments, and has 
also a distinct tail with_a strong fin. The gill-filaments 
are shed previous to the hatching, after which the young 
Ceecilians make their way to the neighbouring stream, 
and live in the water, breathing by means of gill-slits. 
After they leave the water their gill-slits close up, and 
they breathe by lungs. The brothers Sarasin compare 
these Czcilians to Urodeles, in that they pass through 
the perennibranchiate stage in the egg. As larvae they 
are derotrematous, and in the adult stage become true 
land-animals like Salamanders. Our authors also show 
that the spermatozoon has a spiral filament, and that 
there is a fourth gill-arch, from which the pulmonary 
artery is given off. Both these facts tend to show that 
the Czecilians are more nearly allied to the Urodeles 
than to the Anurous Amphibians. 
THE BRITISH ASSOCIATION 
REPORTS 
Fifth Report of the Committee, consisting of Mr. R Etheridse, 
Mr, Thomas Gray, and Prof. ohn Milne (Secretary), appoint:d 
for the purpose of investigating the Earthquake Phenomena of 
Fapan,. (Drawn up by the Secre'ary).—On account of an 
excursion which I have ‘the intention of making during the 
coming summer to Australia and New Zealand, I am compelled 
to draw up this report a month earlier than usual. As the only 
time when the work of attending to observations and experi- 
ments repays itself is during the winter months, I may safely say 
that fmy intention of shortening the time usually devoted to 
NATURE 
4 ' ’ r a 
earthquake observations is not likely to involve any serious loss. ~ 
The number of earthquakes felt during corresponding periods in 
two previous years and this last year were respectively twenty-six, 
thirty-nine, and eighty, and not only have the earthquakes been 
numerous, but some of them have been pretty stiff, as is testified 
by the fact that on several occasions chimneys fell and walls 
were cracked. The work done during the last year is briefly as 
follows :— 
Seisnac Experiments.—Seismic experiments were commenced 
in conjunction with Mr. T. Gray in 1880. The movements 
then recorded were produced by allowing a heavy ball, 1710 lbs. 
in weight, to fall from various heights up to thirty-five feet. 
Subsequently many experiments were made by exploding 
charges of dynamite and gunpowder placed in bore-holes. 
During the last year, whilst working up the long series of 
records which accumulated, several laboratory experiments were 
made to investigate the methods to be employed when analysing 
the diagrams of earth motion. The first of these experiments 
consisted in projecting a small ball from the top of a tall flat 
vertically-placed spring, and at the same time causing the spring 
to draw a diagram of its motion. From the distance the ball 
was thrown its initial velocity could be calculated. From the 
diagram, either by calculation on the assumption of simple 
harmonic motion or by direct measurement, the maximum 
velocity of movement could be obtained. These three quantities 
practically agreed. The most important result obtained by 
these experiments was that they indicated an important element 
to be calculated in earthquake or dynamite diagrams, and, 
further, that in these diagrams the first sudden movement, which 
invariably has the appearance of a quarter-oscillation, ought 
apparently to be considered as a semi-oscillation. The second 
set of experiments consisted in determining the quantity to be 
calculated from an earthquake diagram which would give a 
measure of the overturning or shattering power of a disturbance. 
For this purpose a light strip of wood was caused by means of a 
strong spiral spring and a heavy weight to move horizontally back 
and forth with the period of the spring. On this strip small 
columns of wood were stood on end, and it was determined how 
far the spring had to be deflected and then suddenly released to 
cause overturning. ‘The more important results of all these 
experiments are :— 
I. Effect of Ground on Vibration.—(1) Hills have but little 
effect in stopping vibrations. (2) Excavations exert consider- 
able influence in stopping vibrations. (3) In soft damp ground 
it is easy to produce vibrations of large amplitude and consider- 
able duration. (4) In loose dry ground an explosion of 
dynamite yields a disturbance of large amplitude but of short 
duration. (5) In soft rock it is difficult to produce a disturbance 
the amplitude of which is sufficiently great to be recorded on an 
ordinary seismograph. 
Il. General Character of Motion.—(1) The pointerof a seismo- 
graph with a single index first moves in a normal direction, after 
which it is suddenly deflected, and the resulting diagram yields a 
figure partially dependent on the relative phases of the normal and 
transverse motion. These phases are in turn dependent upon 
the distance of the seismograph from the origin. (2) A bracket 
seismograph indicating normal motion at a given station com- 
mences its indications before a similar seismograph arranged to 
write transverse motion. (3) If the diagrams yielded by two 
such seismographs be compounded, they yield figures containing 
loops and other irregularities not unlike the figures yielded by 
the seismograph with the single index. (4) Near to an origin, 
the first movement will be in a straight line outwards from the 
origin ; subsequently the motion may be elliptical, like a figure 8, 
and irregular. The general direction of motion, is, however, 
normal. (5) Two points of ground only a few feet apart may 
not synchronise in their motions. (6) Earthquake motion is 
probably not a simple harmonic motion. 
Ill. Normal Motion.—(t) Near to an origin the first motion is 
outwards. Ata distance from an origin the first motion may 
be inwards. (2) At stations near the origin the motion inwards 
is great2r than the motion outwards. At a distance the inwards 
and outwards motion are practically equal. (3) At a station 
near the origin, the second or third wave is usually the largest, 
after which the motion dies down very rapidly in its amplitude, 
the motion inwards decreasing more rapidly than the motion 
outwards. (4) Roughly speaking the amplitude of normal 
motion is inversely as the distance from the origin. (5) Ata 
station near an origin the period of the waves is at first short. 
It becomes longer as the disturbance dies out. (6) The semi- 
[ Oct. 1, 1885 | 
