178 
POPULAR SCIENCE NEWS. 
[DECEMnEu, 1S90. 
bubble and prevent it from rising to the sur- 
face. This phenomenon is due to the peculiar 
and complex principle of surface tension, by 
which the thin film at the surface of a liquid 
acts, in a certain sense, like a solid covering. 
By an application of the same principle, a 
cylinder of wire gauze, or even a fine sieve, 
may be filled with water, and needles, or a 
steel pen, be made to float, if carefully placed 
upon its surface. Those insects which walk 
so easily over the surface of ponds and 
streams are indebted to this same principle 
for their support, and not to the inherent 
buoyancy of their bodies. 
The accompanying illustrations are repro- 
duced from La Nature. 
AN ANCIENT GALLO- ROMAN 
SEPULCHRE. 
An interesting archaeological discovery was 
made last July in the Capuchin cemetery 
of Beauvais, near Paris, of a sarcophagus 
and coffin, dating, probably, from the Gallo- 
Roman period of history. While digging a 
modern grave, the workmen came upon a 
heavy stone block, which proved to be the 
top of the sarcophagus, and which, from its 
great weight, was removed with considerable 
difficulty. 
square base was lefl, evidently as a support 
for a monument, of which no trace was 
found. 
One of the most interesting finds in con- 
nection with this discovery was the articles 
of glass, represented in Fig. 2, which were 
placed in the lead coffin at the head and feet 
of the body. Four of the pieces were perfectly 
unbroken, and the glass had the peculiar iri- 
descence which is only formed when it has 
long been buried or exposed to the action 
Fig. 1. 
Inside the stone sarcophagus was found a 
coffin made from sheet lead about one-quarter 
of an inch thick, and this enclosed the body 
of the ancient Roman or Gaul, little of which 
remained except two teeth and the fragments 
of a few bones. The size of these relics 
indicated that the remains were those of a 
man, and their position that, contrary to the 
usual custom, the corpse had been placed 
with its head to the east. The stone sar- 
cophagus was seven feet long, three feet 
wide, and two feet deep, and was estimated 
to weigh over eight thousand pounds. The 
top was bevelled (Fig. i ) , but in the center a 
Fig. 1. 
of the elements. The two large pitchers still 
contained a brownish liquid of faint odor — 
doubtless some ancient perfume left with the 
dead. This substance is to be submitted to 
a' chemical examination. The sarcophagus, 
coffin, and their contents have been carefully 
preserved, and will doubtless find a place in 
one of the many museums of Paris. 
The fact that the locality has been so long 
in use as a cemetery is an interesting one, and 
indicates a greater uniformity in the life of the 
people than one would believe possible in a 
country troubled by so many wars as France ; 
but we think that such is always the case to a 
greater degree than is generally supposed. 
Armies may be raised, battles fought, and 
dynasties change, but the great mass of the 
people must always live out their lives as 
usual, notwithstanding the struggles of con- 
tending forces ; and the many wars and polit- 
ical changes are more important from a his- 
torical point of view than in their actual 
eflect upon the progress towards civilization 
of the people themselves. Curiously enough, 
two modern burials have already been made 
directly over this ancient sarcophagus, — after 
the cheerful French custom of temporary 
sepulture, — and it is not improbable that for 
hundreds of years to come the cemetery 
of Beauvais may remain the last resting place 
of many future generations of the inhabitants 
of the locality. 
The illustrations are reproduced from La 
Nature. 
*•> 
A SINGLE sunflower will produce from 4,000 to 
12,000 seeds in one summer ; the poppy will produce 
32,000. 
[Original in Popular Science Xews.] 
SPECTROSCOPIC MEASURES OF STELLAR 
MOTIONS. 
BY PROF. C. A. YOUNG. 
Everyone knows that the so-called "fixed stars" 
are not really fixed at all, but are moving very 
swiftly. So remote, however, are even the nearest 
of them that it takes centuries to make their drift 
perceptible, and for all but a very few the displace- 
ment in an entire century is so slight that it can be 
detected only by the most careful observations. 
Obviously, too, if a star happens to be moving 
"head on," so to speak, — t. e., either directly 
towards or from us, — it will not change its appar- 
ent place in the sky, and its motion cannot be 
ascertained by any comparison of ancient observa- 
tions with modern. One might, perhaps, think 
that such a motion could be detected by the change 
in the star's apparent brightness; but a very short 
calculation will show that even our nearest neighbor 
(Alpha Centauri), if it were rushing towards us at 
the rate of one hundred miles a second, would 
increase its brightness only about two and a half 
per cent, in a century, and in the case of remoter 
stars the change would be correspondingly less; so 
that the method is practically useless. 
But there is a way in which such a motion can 
not only be detected, but even measured with some 
approach to accuracy ; a method which is not 
affected by the distance of the object observed, 
except in so far as remoteness dims its light. The 
instrument used is the spectroscope, and the princi- 
ple involved is that when the distance between us 
and a star is changing with any considerable 
rapidity, all the lines and markings in its spectrum 
are shifted in position as compared with the spec- 
trum of a similar body at rest. The reason is that 
light consists of pulsations, or waves, coming to us 
at regular intervals of time, and regularly spaced in 
distance, each colored ray having its own place in 
the spectrum according to its wave-length, or 
"pitch," so to speak. Now if a star is comirkg 
nearer, then the waves due, say to the hydrogen in 
the spectrum of its atmosphere, are encountered with 
greater frequency than if it were at rest, and so are 
virtually raised in pitch, and shifted towards the 
violet end of the spectrum, where the waves are 
shortest; and vice versa, of course, if the star is 
receding. 
A good illustration is what would happen if we 
were in a boat anchored in a stream flowing steadily 
at the rate of, say ten feet a second, while another 
person is in a second boat a little way up stream, 
throwing a cork into the water each second. So 
long as both boats are at rest, the corks will pass us 
one a second, at equal intervals of ten feet; but 
if the cork-thiower has his boat rowed up-stream at 
the rate of two feet a second, his corks will strike 
the water twelve feet apart instead of ten, and will 
reach us with twelve feet spaces between them, and 
at intervals of one and one-fifth seconds. If, on 
the other hand, he lets his boat drop slowly down 
stream at the same rate, the spaces between the 
corks will be reduced to eight feet, and the time 
interval to four-fifths of a second. If our own boat 
is put in motion, it is easy to see that the effect will 
be similar. 
Speaking generally, we may say that whenever 
the distance between the observer and any source 
of regularly produced pulses is diminishing their 
interval will be lessened, and rice versa if the dis- 
tance is increasing. All that is necessary, then, in 
order to ascertain the speed with which a star is 
approaching or receding, is to form its spectrum, 
and then to confront it with the spectrum of a 
so-called " Geissler tube," giving the bright lines 
