Cije ^0})ttlar Science 0tMiS 
AND 
BOSTON JOURNAL OF CHEMISTRY. 
Volume XXIV. 
BOSTON, FEBRUARY, 1890. 
Number 2. 
CONTENTS. 
Familiar Science. — The Standard of Length 17 
The Proto- Helvetes. or Lake -Dwellers of 
Switzerland 17 
The Chigger 19 
The Rainy Season of Florida 19 
Scientific Brevities 20 
Practical Che.mistry and the Arts. — Nov- 
elties in Photography _ . 20 
The Scientific Knowledge of the Ancient 
Greeks and Romans 
Zinc 
In Ye Olden Time 
Industrial Memoranda 
The Out-Door World. — Prof Guttenberg"s 
Course in Mineralogy 
New York City Assembly of the A. A. . . 
Reports from Chapters 
Original Observations 
Mole Crickets "... 
Editorial. — Old Proverbs from a Scientific 
Standpoint 
A Double Statue 
Paris Letter 
Interesting Results of Defoliation of Plants in 
the Azores by a Cyclone 
Meteorology for December. 1889, with Review 
of the Year 
Astronomical Phenomena for February, 1890 
Qiiestions and Answers 
Literary Notes 
Medicine and Pharmacy. — Warts .... 
A Simple Water Still 
Chloride of Ammonium in Winter Cough 
Monthly Summary of Medical Progress . 
A Unique Prescription 
Medical Miscellanv 
21 
22 
22 
22 
22 
23 
23 
24 
24 
25 
26 
26 
27 
27 
28 
29 
29 
29 
30 
30 
31 
32 
■32 
Publishers' Column 32 
Fanjiliar Science. 
THE STANDARD OF LENGTH. 
In the United State.s and England the 
standard of length is the yard, and the ques- 
tion ari.ses, How long is a yard .' It may be 
said in answer that a yard is simply an arbi- i 
trary standard which tradition says is based 
upon the length of the arm of Henry VIII. ', 
At present the yard is the distance between i 
two marks upon a certain bar, kept in the 
Tower of London, and if it' should be de- 
I 
stroyed, the exact standard could never be' 
replaced. ! 
To avoid this uncertainty, and obtain a 
fixed and unvarying standard, the French, in 
the last century, made an accurate measure- 
ment of a quadrant of the earth's circumfer- 
ence, and, taking the ten-millionth part of 
this distance, gave it the name of »/e/rr, and 
adopted it as the standard of length. This, 
length, which is equal to about 39.37 inches, ! 
is now in universal use on the continent of 
Europe, and is authorized as a legal .standard 
in nearly all civilized countries. Consider-^ 
able discussion has arisen as to whether the 
original measurement \\ Jis perfectly accurate, ! 
and it seems probable that there was a small 
error, so that if the standard metre now kept 
in Paris should be destroyed, a re-measure- 
ment of the quadrant of the earth would not 
give us exactly the same metre. However, 
the error in any case is a very minute one, 
and the chances are very small that the origi- 
nal standard will ever be destroyed, to say 
nothing of the fact that the numerous copies 
distributed among the various nations of the 
world do not appreciably difter from it. 
The accompanying engraving shows the 
form of these standards, which have been 
copied with most scrupulous care from the 
original metre at Paris. It is probable that 
they do not differ from the standard over 
two ten-thousandths of a millimetre, or one 
five-millionth part of the entire length. 
These standard bars (i) are cast from an 
alloy of platinum with ten per cent, of 
iridium, forming a metal almost as hard as 
steel, practically infusible, and not acted 
upon by chemical reagents. The measure- 
ments are marked upon the surface A, (i), 
and the peculiar shape of the bar is especially 
calculated to endure a strain without bending ; 
and, in fact, a slight deflection — as shown, 
much exaggerated^ in 2 — will not materially 
alter the length of the face on which the 
scale is engraved. It has been proved that a 
weight of eighty pounds may be placed on 
one of these bars, while supported at the 
ends enly, without permanently altering its 
shape. 
The standard of weight is the gramme, 
which is the weight of a cubic centimetre of 
water at 4° C. — its point of maximum density. 
Practically, the standard at Paris is a block 
of the platinum-iridium alloy weighing one 
thousand grammes, or one kilogramme. 
Copies of this- standard of weight have also 
been made for the several nations comprising 
the International Metric Conference, and it 
is believed that they do not vary more than 
one hundred-millionth from the original — a 
dimension which is utterly imappreciablc. 
A meeting of the International Conference 
was held at Paris last September, when the 
work of the committee who prepared the 
various standarids was ratified, and the stand- 
ards accepted for the respective nations. The 
successful completion of this work, which 
has been in progress for about fifteen years, 
marks an epoch in scientific progress, and 
denotes an amount of care, skill, and accuracy 
on the part of those having the work in 
charge, which cannot be realized by anyone 
except those directly concerned in it. The 
simultaneous destruction of these widely scat- 
tered standards of measure and weight is 
almost impossible, but even in such a remote 
contingency, another measurement of the 
earth's circumference would practically give 
us back our metre, with no important change 
from its original length. 
A^ 
[Original in Popular Setaice Xewt.] 
THE PROTO-HELVETES, OR LAKE- 
DWELLERS OF SWITZERLAND. 
BY ADA M. TROTTER. 
The little town of Morges is picturesquely situated 
on a bay formed by the waters of Lake Leman. It 
boasts, among other attractions, a beautiful view of 
Mont Blanc. The castle (now used as an arsenal), 
the church, the quaint houses, with the castle of 
Wufflens on the heights, are very ancient — supposed 
to date back to the Roman occupation of the coun- 
try. The ancient city, however, which attracts the 
attention of scientists to this charming spot, is not 
the Morges visible to the eye. Those stone imple- 
ments and the rude pottery which the Museum of 
Antiquities at Lausanne displays as from the 
"ancient city of Morges," belong to pre-historic 
times, dating back to ages before the Romans set 
foot in Helvetia. 
But if the Lacustres, or lake-dwellers, were a 
pre-historic race, how are we to learn anything 
about them .' The archneologists, to whom we look 
for the solution of this problem, do not fail us; one 
by one they have wrested the objects in the 
museums from the bottom of the lake, and from 
them have evolved a history of the habits and cus- 
toms of this interesting people. The lakes of 
Switzerland kept jealous guard of the secrets com- 
mitted to their charge. A mere accident revealed 
the pre-historic occupation of the country. A bone 
implement, rudely fashioned, was found bv a scien- 
tist in a marsh. A small thing this; still, falling 
into the right hand*, enough to open out a new 
field of archaeological research. 
But, before we follow the labors of the patient 
men of science, it will be well for us to take advan- 
tage of the oppol-tunity this visit to Morges affords 
us, to see for ourselves the site of one of the cities 
of the Lacustres. We must take a boat, for the 
palafittes* of this primitive people were built on 
*Term universally used to express " Ikke-dwellin^,*' from Ihe 
IUIi»a Pala rUte. 
