Rodolfo Amedeo Lanciani.

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sonian observers ; and it is to be hoped that the Secretary of that
Institution will furnish us with such a summary for each year since
the Smithsonian system of meteorological observations was com-
menced.

The following summary of the auroral observations made for
five years at DepauviUe, N. Y. (lat. 44° 1' N. long. 76° 3' W.) has
been famished by Mr. Henry Haas.

Jan. Feb. March. ApiH. May. Jane. Jnij. Ang. Sept. Oct. Kov. Deo. Year.



1865


2


3


3


6


1


6


6


5


4


6


2


2


42


1866


1


1


4


8


7


2


3


4


6


6


4


2


42


1867


2


1


4


3


6


2


3


6


10


6


2


1


44


1868


3


3


10


4


6


4


3


3


2


1





1


40


1869


4


1


4


6


6


2


4


4


8


1


2


3


44



The number of auroras reported for the different years is re-
markably uniform, and similar results have been found at other
stations where the annual number of auroras rises as high as fifty
or upwards; but in lower latitudes where auroral displays are
less frequent, the indications of periodicity are unmistakable.

V. MISCELLAKEOUS SCIENTIFIC INTELLIGENCE.

1. Varioitions in the Eccentricity of the EartKs Orbit. — ^In voL
xlvi of this Journal (1868), Prof J. N. Stockwell has a paper, with
a chart, illustrating the variations in the eccentricity of the Earth's
orbit for the past one million of years, starting from a point 175,000
years back of the present time ; and in an earlier memoir " On the
Secular Equation of the Moon's mean motion " published at Cam-
bridge in 1867, he has given a similar chart for the million of years
following. His calculations were made for intervals of 10,000
years, and hence they are much more exact than the earlier chart



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148 MiscdUmeoua IntdUgenee.

of Croll, whose intervals were, for the major part of it, 50,000
years. The main point put forward by rtot Stockwell in his
Cambridge memoir nas not been accepted by astronomers, but this
does not affect his calculations of the eccentricity. According to
his results for past time, a low maximum occurred about 100,000
years back ; a nigher, 200,000 years ; a lower, 800,000 ; a rather
low minimum 4^0,000; a low maximum, 475,000 ; a very low mini-
mum, 520,000; a maximum, 670,000; two maxima, the second
750,000; a very low minimum 800,000; an extreme maximum,
850,000 ; another very low minimum, 900,000 ; a high maximum,
950,000 ; etc. — In future time, there will be a very low minimum,
24,000 years on ; a low maximum, 160,000 years ; another low max-
imum, 250,000 ; a very low minimum, 300,000 ; a low maximum,
400,000; a very high maximum, 515,000; a minimum, 560,000 ; an
extreme maximum, 610,000 years ; and so on. Some of the minor
undulations, and most of the minima, are not here noted.

2. Note on an Electrification of an Idand; by F. Jekkin. —
A curious discovery has been made by Mr. Gott, the superinten-
dent of the French company's telegraph station at the little island
of St. Pierre Miquelon. lliere are two telegraph stations on the
island. One, woiied in connection with the Anglo-American com-
pany's lines by an American company, receives messages from
Newfoundland and sends them on to Sydney, using for uie latter
purpose a powerful battery and the ordinary Morse signals.

The second station is worked by the French Trans-atlantic Com-
pany, and is famished with exceedingly delicate receiving instru-
ments, the invention of Sir William Thomson, and used to receive
mbssages from Brest and Duxbury. These very sensitive instru-
ments were found to be seriously affected by earth-currents ; Le.,
currents depending on some rapid changes in the electrical condi-
tion of the island ; these numerous changes caused currents to flow
in and out of the French company's cames, interfering very much
with ttfe currents indicating true signals. This phenomenon is not
an uncommon one, and the inconvenience was removed by laying
an insulated wire al>out three miles long back from the station to
the sea, in which a large metal plate was immersed ; this plate is
used in practice as the earth of the St. Pierre station, the changes
in the electrical condition or potential of the sea beins small and
slow, in comparison with those of the dry rocky soil of St. Pierra
After this had been done, it was found that part of the so-called
earth-currents had been due to the signals sent by the American
company into their own lines, for when the delicate receiving in-
strument was placed between the earth at the French station and
the earth at the sea, so as to be in circuit with the three miles of
insulated wire, the messages sent by the rival company were
clearly indicated, so clearly indeed, that they have been automati-
cally recorded by Sir William Hiomson's syphon recorder. An-
nexed is a facsimile of a small part of the message concerning the
loss of the steamship Oneida, stolen in this manner [here omitted.]

It must be clearly understood that the American lines come no-
where into contact, or even into the neighborhood of the French



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MiseeUanecms InkUigence. . 149

line. The two Btations are Beveral hundred yards apart, and yet
messages sent at one station are distinctly read at the other sta-
tion; the only connection between the two being through the
earth; and it is quite clear that they would be so received and
read at fifty stations in the neighborhood all at once. The expla-
nation is oDTious enough: the p9tential of the ground in the
neighborhood of the stations is alternately raised and lowered by
the powerM battery used to send the American signals. The po-
tential of the sea at the other end of the short insulated line remams
almost if not wholly unaffected by these, and thus the island acts
like a sort of great Leyden jar, continually charged by the Ameri-
can battery, and discharged in part through the short insulated
French line. Each time the American operator depresses his send-
ing key, he not only sends a current through his hues, but electri-
fies the whole isUmd, and this electrification is detected and
recorded by the rival company's instruments. ♦ ♦ ♦

All owners of important isolated stations should use earth-plates
at sea, and at sea only. This plan was devised by Mr. C. Variey
many years ago to eliminate what we may term natural earth-
currents, and now it should be used to avoid the production of
artificial earth-currents which may be improperly made use of. —
Nature^ May 6th, 1870.

3. Baron von Richthofen^B Explor(xtion8 in China, — ^The Baron
V. RiCHTHOFBN, formerly of the Geolorical Survey of Austria,
accompanied Mr. J. Ross Brown to China two years ago, and
since then has occupied his time in making geological explora-
tions in China. His investigations have been encouraged by the
generous subscription of 16,000 dollars, made by the American
merchants of Chma to aid him in prosecuting such exploration.
An interesting feature of this subcription is that he is at liberty to '
use it as he deems best for the interests of science, without regard
to immediate commercial or economic results, and in addition to
his geological work, he purposes to institute meteorological obser^
vations at several points.

Already many important additions have been made to the knowl-
edge of the geology of Northern China and Manchuria. Some of his
observations made between Shanghai, and Han-kau were published
in the Proceedings of the American Academy of Boston, vol. viiL
Since these were written other letters have been received by Prol
J. D. Whitney, from which we hope to make extracts for a future
number of this JoumaL

4. Thermal UhiU. — Prof T. Mtjib proposes in ** Nature" of April
14th, the introduction of the word therm for a thermal unit, mak-
ing that unit the quantity of heat necessary to raise the temperatu/re
of 1 gram of waiter from O*' C. to 1° C. Therm^ hectothe^, hilo-
therm would be consequently the expressions for respectively
1,100, 1000 therms, suggestively corresponding to gram, hecto-
gram, kilogram in name as well as in nature.''

6. Astronomer at the Cape of Good Hope. — ^Mr. E. J. Stone, P.
R.S., of the Greenwich Observatory, has received an appointment
to this position. — Nature^ June 28.



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150 Miscellaneous Bibliography.

6. American Association, — ^The American Association for the
Advancement of Science will hold its next meeting in Troy, com-
mencing on the first Wednesday in August. Pro£ vTilliam Chau-
venet is the President for the year.

7. British Association, — The next meeting of the British Asso-
ciation will be held at Liverpool on Wednesday, the 14th of Sep-
tember, under the Presidency of Prof Huxley.

8. Admiral Russell Henbt Manitebs, President of the Astro-
nomical Society of London, died recently, aged 70 years.

rV. MISCELLANEOUS BIBLIOGRAPHY.

1. A concise analytical and logical Development of the Atmos-
pheric System as God made it ; and the Elements of prognosticor
tion by which the toeather may be forecasted; designed as a
Weather-book for the practical mind of the Country ; by Thoicas

B. Butler. Hartforc^ 1870. 404 pp. 8vo. — ^This work on Meteor-
ology will be read with profit by all interested in the subject. It
presents a large number of facts of the Author's own observations,
together with others from various sources, and is illustrated with
many woodcuts. The title is calculated to excite a prejudice in
scientific minds aeainst the volume, and many would at once sub-
stitute for " The Atmospheric System as God made it," " Hie At-
mospheric System as Thomas B. Butler makes it." The subject is
too large a one to be discussed in a book notice ; and we refer,
therefore, to the volume for the views, which, according to the
motto on the title pa^e, is, in the author's opinion, " the truth
[that] is mighty and will prevail"

2. /Synopsis of the Extinct BaJbrachia and Reptilia of North
America : Part 2d. By Edward D. Cope. — This second part of
Prof Cope's important work on the Extinct Batrachia and Rep-
tilia of North America includes the synopsis of the remainder of
the Dinosauria, the Testudinata, the Pterosauria, the IVthonomor-
pha, and the Ophidia. The Testudinata are divided into two
groups : the Cryptodira, represented bv thirty-four species which
are referred to tourteen genera, and the Pleurodira, represented
by ten species of four genera. Bhabdofelix longispinis Cope is
the only known North American representative of the Pterosauria.
Of the Pythonomorpha, the author mentions twenty-seven species.
Three S{>ecies of the Ophidia are given. Several additional Keptil-
ian speoies are remarked upon in the Appendix, and one new genus
of the Cheloniidffi is defined. Prol Cope, through his labors, is
throwing great light on the ancient vertebrate life of this continent.

8. Mrst Principles of Chemical Philosophy : by Josiah P.
CooKE, Jr., Erving Professor of Chemistry and Mineralogy in
Harvard College. 634 pp. text and 22 tables and index, 12mo. —
The first part of Prof. Cooke's Chemical Philosophy was noticed
in a former volume of this JoumaL That portion of the work, it
will be remembered, was devoted to the development of the fun-
damental principles of chemical science. In the second part of his
treatise, the author gives a succinct, but very comprehensive, sum-
mary of the more important elements and compounds, exhioiting



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Miscellaneous Bibliography. 151

their constitution and relation by means of formnlae and reactions,
illustrated by problems calculated to direct the attention of the
student to the more important facts and principles of the science.

By his method of developing the subiect, rrof. Cooke succeeds
in giving to chemistry a high degree of logical sequence and math-
ematical exactness, and his work, taken in connection with a good
book of laboratory practice, will be found a most efficient aid to
both teacher and pupil in the study of chemistry.

4. Neue Untersuchungen Uber den elektrisirten Sauerstoff: von
Dr. G. Meissnbb. Mit zwei lithographirten tafeln. GOttmgen,
1869. 4to, pp. 110, — This brochure, re-published from the Transac-
tions of the Royal Academy of Sciences in Gdttingen, contains the
experiments made by the author, with the aid of his previous ex-
perience, in support of his opinion that the so-called atmizone or
antozone fog consists only of electrified oxvgen and water; an
opinion stated in his previous research published in 1863. An ab-
stract of this supplementary memoir of Meissner will appear in
our next number.

5. Greait Outline of Geography: a TeaOrBook to accompany
the Universal Atlas; by Theodobb S. Fay. 238 pp. 12mo. New
York, 1869. (G. P. Futnam & Son). — ^Mr. Fay has made an impor-
tant contribution to our means of instruction in geography in the
Atlas and its accompanying text, lately published by Futnam &
Son. The work has been long in preparation, the map having
been prepared by Hassenstein of Berlin, during the author's long
residence as American Minister at European courts. A fac-simile
of a letter received by the author from Humboldt expressing his
approval of it, is given in the volume. The number of plates con-
stituting the atlas is eight, the most of them double and all well
executed. They give, as far as the limited space allows, the chief
astronomical, pohtical and historical features of geography, to-
gether with some of the physical, and are presented in a clear
and striking manner. The text consists partly of brief explana-
tions of terms and principles, and of historical, geoeraphictu and
otiiier observations, out mainlj of lists of places to be looked out
on the maps. The plan of mstruction proposed in the work is
for the teacher to read the lesson from the book while the pupil
before him " follows every word upon the plates," looking for me
cities, rivers, <&c., as the names are mentioned ; and this exercise,
which is not to exceed, at any one time, an hour, is study enough.
The pupil who goes through with the work under the guidance of
a patient teacher cannot fail to become well acquainted with the
suDJect.

6. Geology and Bevelation ; or the ancient history of t?ie earth
considered in the light of Geological facts and revealed religion^
with Illustrations ; by die Rev. Gbbald Molloy, D.D., Professor
of Theology in the Royal College of St. Patrick Meynooth. 418
pp. 12mo. London, 1870, (Longmans,*Green, Reader and^Dyer^.
— ^No book on this subject has appeared from the theological side
that is more worthy of respect than this by Dr. Molloy. The
author's dbcussion oi the prmoiples of geology, with reference to



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162 MiaceUaneoua Bibliography,

their bearing on the Mosaic histoiy of Creation evinces great
flEuniliarity with the science and the necessities of the unscientific
reader, and thorough knowledge of the sacred record. In treating
of the antiquity of the earth he enforces his argument by copious
quotations horn the Christian Fathers, showing that lone before
geology had any existence as a science, and of course, when the
discussions and doubts it has excited were unknown, the essential
points respecting time and the order of Creation had received
careful attention from devout thinkers, and that the conclusions, at
which they arrived on purely theological grounds, were in most
cases mucn the same as those which the best writers of our time
deduce from geological evidence. Dr. Molloy closes his argu-
ments as follows : — •" We have then two distinct systems of inters
pretation according to which the vast antiquity of the earth
asserted by geology may be fairly brought into harmony with the
history of creation recorded in Scripture. One allows an interval
of incalculable duration between the Creation of the Heavens and
the Earth, and the work of the six days ; the other supposes each
one of the six days to have been itself an indefinite period of
time.'' The questions touching the antiquity of the human race
the author proposes to discuss separately at a future time.

We understand that this work will soon be issued from the pub-
lishing house of Q. P. Putnam & Son of New York.

7. MdiquioB AquUcmicWy being contributions to the ArchcBology
and Palceontology of PMgord and the acfpining Provinces cf
Southern France; by E Labtbt and Henby Christy, edited by
Thomas Rupebt Jones, Pro£ G^eoL, etc.^ Roy. MiL College, Sana-
hurst. Part X, for February, 1870, carries the work to pages 140
and 132 in its two parts, the plates to A xzzn, and B xvm.

Report of the Ck>mmi88ioner of Agriculture for the year 1868. 671 pp. Wash-
ingtoiif 1869.

Annual Report of the Trustees of the Museum of Oomparatiye Zoology, at
Haryard College. 42 pp. 8yo. Boston. 18*70.

First Annual Report of the American Mui^eum of Natural History. pCoaeom in
the New Yoric Park.] 30 pp. 8vo. Jan. 1870.

TransactionB of the Edinburgh (Geological Society, Vol I, Parts I, n, m, 372 pp.
8vo. with many plates. 1868-1869. Edinburgh.

Tables for the determination of Minerals; by Thomas Egleston, Jr., Prof. lOn.
and Met, in the School of Mines of Columbia College. 26 pp. Sva New Yoik,
1870.

A Treatise on Elementary Geometry, with appendices oontaimng a CoUeotlon of
Exerdses for students and an introductioD to Modem Geometry; by WiDiam
Chauyenet, L.L.D. Prof, of Math, and Astr. in Washhigton Uniy. 368 pp. Sva
Philadelphia, 1870. (J. B. Lippinoott)

On Eozoon Canadense, by Professors William King and T. H. Rowoey. of Queen's
Uniy., Ireland. 48 pp. 8yo.. with 4 colored plates. From the Proc. R. Irish Acad..
July, 1869. [Facts and arguments against the animal nature of the Eozoon, (hm
which we may dte at another time].

Report of the British Association for 1869. cv, 434 and 260 pp. London, 1870.

GnmdK&ge einer allgemeinen Theorie der OberflSohen in syi^etisoher Behaod-
hmg, yon D. Ludwig ^mona, l^f. Berlin. 1870.

Annali di Mathematica pura ed applicata, diretta da F. Briosdiie L. Cr^nona,
8er. n, Milana

The American Colleges and the American Pubho; by Noah Porter, D.D., Pro>
feasor in Yale College. 282 pp. 12ma NewHayen, Conn., 1870. (C. C. Ghatfleld
&Co.)



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THE

AMERICAN

JOURNAL OP SCIENCE AND ARTS.

[SECOND SERIES.1



Art. XVL — Oomparison of the mean daily range of the Magnetic
Declination^ with the nurnber of Auroras observed each year, and
the extent ofiheblack Spots on the suTface of the Sun; by Elias
Looios, Aofessor of Natural Philosophy in Yale CoUega

In 1820, M. Schwabe of Dessau in Germany commenced a
series of observations of the solar spots which he has continued
to the present time. For each year he has kept a record of the
number of days of observation, the number of groups of spots
observed, and the days on which the sun was §ee from spots.
These observations decidedly indicate a periodicity in the nilm-
ber of the solar spots, a maximum recurring at an interval of
from 7 to 18 years. In 1849, Dr. Rudolf Wolf, of Zurich,
Switzerland, commenced a series of observations for the same
object as those of Schwabe, but upon a plan somewhat more
precise and thorougL For each day of observation he recorded
two numbers; the first showed how many groups or isolated
spots were seen with a four-feet Fraunhofer telescope and a
magnifying power of 64 ; the second showed the total number
of visible spots for that day. In order to deduce from these
observations a series of numbers which shall be proportional
to the amount of spotted surface of the sun, he multiplies
the number of groups for each day by ten, and adds to this

Eroduct the total number of spots. Thus, if on a certain day
e counts 9 ^ups and 81 single spots, he obtains 121
(9 X 10+81) which he calls the relative number. The mean of all
the numbers thus obtained for a month, is the relative number
for that month ; and the mean of the number thus obtained for
Am. Jour. Sol - 8boond Ssbibs, Tol. L, Na 149.— Sm., 1870.
10



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154 E, Loomis en Solar SpotSy Magnetic Declination, etc

a year is the relative number for that year. Dr. Wolf has con-
tinued these observations to the present time, and they show
clearly a minimum in 1856 and another in 1867, the interval
being 11 years.

Dr. Wolf has made a most thorough examination of the
records of Astronomical observers, since the invention of the
telescope in 1608, and has aimed to deduce a similar series of
numbers which shaD be proportional to the amount of spotted
surfece of the sun for a penod of 260 vears. In this attempt
he has been remarkably successful, and he claims to have cie-
termined the date of eveiy maximum and every minimum of
the solar spots since 1608. He has also published a table of
relative numbers for each year since 1700, in which, however,
we find 86 years marked with an interrogation point, indicating
that the numbers for those years are specially unreliable, or
were derived by interpolation. Since 1749 only 12 years are
thus marked with an interrogation point These years are 1774,
1792, 1798, 1801 to 1807, and 1814-^. From 1749 to 1825,
the numbers for 87 years are claimed to be specially reliable.

The following is a list of all the important observations since
1700 from which these numbers are derived. All the refer-
ences are to " Vierteljahrschrift der Naturforschenden Gesell-
schaft, in ZuricL"

Obfl. from 1700-1748 by Kirch, voL 12, Obs. from 1794-1830 by Fkragerguee,



p. 142.
1706-1726 by Plantade, vol 6,

p. 258.
1718-1726 by Boat and Alls-

ches, YoL 6, p. 261.
1742-1751 by Hagen, toL 4,

p. 250.
1749-1799 by Staudaoher, vol.

2, p. 277.
1764-1760 byZuoooni, toL 2,

p. 285. .
1769 by Horrebow, voL 10, p.

281.
1773-1777 by MaUet, toL 3, p.

394.



vol 6, p. 433.
1800-1818 by Heinrich, toL

4, p. 86.
1813-1836 by Stark, roL 3,

p. 373.
1816-1826 by Tevel, voL 4, p.

239.
1819-1823 by Adama, toL 6,

p. 449.
1826-1868 by Schwabe, toI. 1,

p. 266 ; vol 6, p. 1, eta
1849-1868 by Wolf, vols. 1, to

14.
1864-1860 by CarriDgton, toL

9, p. 248.



I have no reason to doubt that the relative numbers which
Dr. Wolf has derived from these observations are generally as
accurate as can be deduced from the materials employed, but I
ttink his numbers need some correction for the years 1798 and
1794 and probably also for 1795. His numl>ers from 1787
to 1795 are



1787 92-8*

1788 90-6*

1789 854



1790 75-2

1791 46-1

1792 52-7?



1798 20-7?

1794 28-9

1795 16-5



I propose to examine into the accuracy of these numbers for
1798 and 1794



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K Loomis on Solar S^pots, Magnetic Decimation^ etc 155

The relative numbers fix)in 1787 to 1798 depend almost en-
tirely upon the observations of Staudacher. On p. 288, voL 2,
WoIj^ by comparing the average number of spots on each day
of ol^ervation, deduces the following niimbers :



1787.


1788.


1789.


1790.


1791.


1792.


1793.


46-4


45-8


89-4


87-6


22-8


21-7


17-0





Avenge d^DT No. ot




Dwfc


GroniM. Bpoti.


BeiattTeNo.


85


117 4-28


15-9


51


1-22 2-20


14-4



The relative numbers which he gives for 1787 and 1788 are
obtained by doubling the corresponding numbers here given
for those years ; and applying the sapie rule to 1798 we obtain
84 as the relative numoer for that year. K we combine with
Staudacher's observations, the six observations made by Huber,
Hahn, and Bode we shall obtain almost exactly the same residi
I, therefore, adopt 84 as the most probable relative number for
1798.

The relative number for 1794 depends chiefljr upon the ob-
servations of Flaugergues, and I will compare his observations
for 1794 with those for 1816, for which year Wolf considers
the relative number as well determined ; and I will also include
15 dajrs (Sept 12 to 27, 1794) as being without spots. The
following is a summary of the results :

Groups. Spots.

1794, 41 148

1816, 62 112

The relative number which Wolf adopts for 1816 is 45 '5.
The above result for 1794, reduced to the same scale, becomes
50'2. If we combine with the observations of Flaugergues,
observations on 15 days made by Ende, Herschel, Bode and
Staudacher, this relative number will be somewhat increased.
I therefore adopt 50 as a number not too great for the relative
number of 1794, in place of 28*9 given by Wolf. A similar
analysis applied to the observations of 1795 would g^ve 85 as
the correct relative number instead of 16*5. The maximum for
1804, Dr. Wolf estimates at 70 ; but this number is altogether



Online LibraryRodolfo Amedeo LancianiThe American journal of science and arts → online text (page 70 of 109)