Rodolfo Amedeo Lanciani.

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trench on its simplicity. One or two of these modifications are
now in daily^ use in mj laboratory, for which there is no claim
to any special originality, nor are they intended to supplant the
ordinary form.

As simple an instrument as the Bunsen burner appears to be,
its principles and effects are well worthy of being carefully
studied.

As the gas passes from the small orifices* in the lower part
of the burner, and mixes witii the air drawn in at the lower
opening, and passes out at the open end of the tube, it usually
contains not auite enough oxygen for its complete combustion,
and requires nree access of air to the outer portion of the flame

* The outlet for gas may be in the form of croBsed slits or two small holes of
(1-32 inch diameter each) for the smaU size burner, the length of tube being about
4 to 4i^ inches \on^; the next larger has four openings (about 1-26 indi diamet^
eadi) and the tube about 6 inches long.



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J, L. Smith on flame heat in the Chemical Laloratory. 848



to complete the combustion ; yet even with this, the flame is
hollow in its lower portion, having a cool center, its most in-
tense heat being at about three or four inches above the end of
the tube in the smaller Bunsen-bumers, and eight or ten inches.
in the largest size. If a proper access of air is not allowed toe
the flame, as sometimes happens in some of the furnace con-
nections occasionally used with Bunsen*s burner, acetylene is
formed from the imperfect combustion, which is recognized by
its disagreeable odor, or by collecting some of the gas formed
during the combustion ; the presence of acetylene may be ren-
dered evident by a small amount of a solution of ammoniacal
cuprous chlorid.

The best heating effects of the gas used in the ordinary round
Bunsen burner, when employed in the heating of crucibles and
other vessels, are not obtained ; yet in the great majority of
cases the small loss of gas is not worth considering, especially
as to obtain better results in most cases, would only complicate
this beautifully simple instrument

To get the best effects of heat, we must imitate the principle
appli^ in the Argand burner, namdy to flatten down the exit
of the mixed gases. It was by following out this principle that
Mr. Gore was enabled to make a bomer having a number of
radial flat orifices as repre-
sented in the figure (1), the
air from without having firee
access to the flame along the
entire length of the slit open-
ings, the number of slits used
are more numerous than those
represented in the figure.
With the flame from this
burner introduced into a cer-
tain form of refractory cylin-
ders, cast iron can be melted
in a crucible, without the aid
of a blast, as has already been
stated ; the little chimney to
the furnace being two inches
in diameter, and four feet
long. This burner and its furnace is of but limited applica-
tion, and the amount of gas consumed considerable.

The principle, however, of the above burner is introduced in
constructing a more simple form, and the flattened orifice is
now used in the construction of what I conceive to be the best
form of fiimace for heating glass tubes for or^nic analyses and
other purposes ; such furnaces are made by W eisnig of Paris,
and Desaga of Heidelberg.




The opeBlDgi ftt the exit of Oore*t burner.



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f



844 J. L. Smith on flame heat in the Chemical Laboratory.

The use of the flattened burner is not fully appreciated ; its
advantages are, that there is no cold point in the name, and the
burner can be brought much nearer to the object to be heated,
within 20 to 25 miUinieters for the small sized burners. In
this burner as usually made, the opening is too broad, experi-
ence having convinced me that a slit 2 millimeters across and
about 40 millimeters in length is the most effective one for a
small size burner, consuming about 6 J cubic feet per hour;
this burner is represented in fig. 1, which can, be usea with the
ordinary tube, by detaching the tube with the flattened orifice.
By taking a burner of this description and putting two pieces
on each side of the center, as represented in fig. 2, a very effi-
2 3 cient burner is made for heat-

ing platinum crucibles in sil-
ica fusions, &c., and with such
a burner, consuming 5^ to 6
) cubic feet of gas per hour, I
conduct most effectually all
silica fusions in one hour or
less, taking care to protect
the crucible fix)m the current
of the air by a properly con-
structed short conical chim-
ney, which chimney can be
made of soap stone, sheet
iron, or any other convenient material.

As was stated in the commencement of this article, it was
not intended to describe the more complicated methods of burn-
ing gas in furnaces and by means of a blast, but to confine the
remarks to the simpler forms in every day use, which can be
made to accomplish all the requirements of the usual laboratory
operations, and when a higher heat is required, the furnace
must be our recourse, whether burning gas, charcoal or coka
The burner represented in figure 2 is tne one I now employ in
heating the crucible in my method of alkali determination with
carbonate of lime and sal ammoniac, which method, with its
more recent modifications, will be published in a very short
time. The description of it, with all the minute details of
manipulation, being ready for the presa






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C Albe on Terrestrial Temperature and Solar J^ts, 845



Art. XXXV. — On the connection between Terrestrial Temperaiure
and Solar Spots ; by Cleveland Abbe, Director of the Cin-
cinnati Observatory.

We are indebted to Sir Wm. Herschel for the suggestion that
probably the presence of numerous spots on the surfiace of the
sun is indicative of increased chemical activity, and is accom-
panied by increased radiation of heat The investigations and
theories of the past ten years however would lead us to an
opposite conclusion fiom that bi Herschel.

immediately on the receipt of the Astronomische Nachrichten
containing Wolfs tabular view of the relative frequency of the
solar spots for the past three centuries, I made an extended
comparison of the numbers therein given with such meteoro-
logical tables as were then accessible to ma After much labor
I was forced to conclude that the variations of solar heat are so
slight that they are masked in the local climatic peculiarites.

On further reflection, however, it seemed certain that the
heat radiated from a dark spot should be of low intensity, and
would therefore be largely absorbed by the aqueous vapor of
our own atmosphere as well as by that of the sun. I have
therefore been latelv led to make a special study of the series
of observations maae on the Hohenpeissenberg, and published
in the supplementary volume L of the Annals of the Munich
Observatory.* This series specially deserves attention because
of the remarkable uniformity of the circumstances under which
the observations were madte; it extends from 1792 to 1850,
omitting the years 1798, 1799, 1811, 1812 and 1817.

Assuming that the number of visible solar spots or gwmps
are an index of the existing solar radation of heat, we have but
to compare the number {s) expressing the relative spot frequency
as given by Wolf with the mean annual temperature, (^) as
given by Lamont The solution of the equation ^=^+^ gives
us ^ and t, which latter is the coefficient of solar spot influence
on the radiation of heat

The accompanying table exhibits for each year the value of
s and ^, — ^tiie latter expressed in degrees of Reaumur.

The arithmetical mean of the annual temperatures gives

Mi=+5^178d=0^-061
prob. error of one annual mean =±0*449
The residuals are given in the column <i— wij.

Introducing the term ^ we find by the melhod of least squares
(<j)=+5^-450(d=0^-086)~5X0*'-00789(db0^-00204)
p. e. of one annual mean =d:0°*480.

4> Volume Vn, oantainmg the oontinuatioii of thia series hM not jet been
reoeived.
Ax. JouB. Sol— SxcoHi) Sbbixs, Vol. L, No. 150.— Nov., ISTO*
93



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846 C. Abbe on Terrestrial Temperature and Solar JS^ts.
The residuals are given in the colmnn ^— (^).



Year.


8.


ti


<,-m,


<!-(*.)


it


U—nh


«.-(«






o


o


o


o


o


o


1792,


63


5*38


+ 0-20


+ 0-38


+ 7-11


+ 0-28


+ 43


94


24


616


+ 0-98


+ 0-90


7-77


+ 0*94


+ 0-85


95


16


566


+ 0-48


+ 0-34


7-32


+ 0-49


+ 0*34


96


9


5-36


+ 0-18


-002


6-90


+ 0-07


-014


97


6


606


+ 0-88


+ 0-66


7-77


+ 0-94


+ 0-71


98,


3


5-30


+ 012


-013


7-61


+ 0-78


+ 0-63


1800


10


6-24


+ 1-06


+ 0-87


8-68


+ 186


+ 1-66


01


31


5-56


+ 0-38


+ 0-36


7-23


+ 0-40


+ 0-37


02


38


4-64


-0-64


-0-61


7-50


+ 0-67


+ 0-70


03


60


4-84


-034


-0-22


6-56


-0-27


-015


04


70


6-31


+ 013


+ 0-41


6-87


+ 0-04


+ 32


06


60


409


-109


-0-97


6-67


-116


-1-04


06


30


6-24


+ 106


+ 1-03


7-64


+ 0-71


+ 0-67


07


10


6 87


+ 0-69


+ 0-60


7-44


+ 0-61


+ 0-41


08


2


4*90


-0-28


—0-63


6-47


-0-36


-0-62


09


1


6*09


+ 0-91


+ 0-65


6-80


-0-03


-0-30


io»





6-56


+ 1-88


+ 111


8-20


+ 1-37


+ 1-09


13


14


4 39


-0-79


-0-95


6-07


-0-76


-0-93


14


20


4-34


-0-84


-0-95


616


-0-67


-0*79


16


36


4 05


-113


-112


615


-0-68


-0-68


!«♦


46


3-66


-1-52


-1-43


5-31


-1-62


-1-43


18


34


6-57


+ 0-39


+ 0-39


7-30


+ 0-47


+ 0-46


19


22


6'58


+ 0-40


+ 0-30


7-30


+ 0-47


+ 0-27


20


9


4-38


-0-80


-100


6-21


-0-62


-0-83


21


4


6-42


+ 0-24


0-00


707


+ 0-24


—001


22


3


6-37


-119


+ 0-94


809


+ 1-26


+ 1-01


23


1


4-82


-0-86


-0-62


6-67


-016


-0-43


24


7


6-83


+ 015


-0-06


6-86


+ 0-02


-0-20


26


17


5-27


+ 009


-0-06


700


+ 017


+ 0-03


26


29


516


-0-03


-007


6-80


—0-03


-0-08


27


40


506


-012


-0-07


616


-0-68


—0-63


28


62


6-46


+ 0-28


+ 0-42


7-04


+ 0-21


+ 0-35


29


64


3-99


-119


-.103


5-06


-1-77


-1-63


30


59


5-00


-018


f002


6-30


-0-63


-0-34


31


39


5-39


+ 0-21


+ 0-25


6-87


+ 004


+ 0-07


32


22


4-96


-0-22


-0-32


6-70


-013


-0-23


33


8


617


-001


-022


6-07


-0-66


— 0-97


34


11


6-99


+ 0-81


+ 0-63


7-88


+ 105


+ 86


35


46


4-69


-0-49


-0-40


6-26


-0-57


-0-48


86


97


4-98


-0-20


+ 0-30


6-61


-0-32


-018


37


111


4-23


-0-96


-0-34


5-74


-109


—0-48


38


83


4-20


-0-98


-0*60


6-76


-107


-0-68


39


68


610


-0-08


+ 0-20


6-82


- 01


+ 0-26


40


52


4-38


-0-80


-0-66


6-96


- -87


-0-73


41


30


6-60


+ 0-42


+ 39


7-37


+ -64


+ 0-50


42


20


609


-009


-0-20


6-80


- -3


-015


43


9


524


+ 006


-014


6-79


- -4


—0-25


44


13


4-67


-0-51


-0-68


6-32


- -61


-0-«8


46


33


4-87


—0-31


-0 32


6-58


- -26


— 0-J6


46


47


624


+ 1-06


+ 116


7-87


+ 1-04


+ 114


47


79


5-06


-013


+ 0-22


6-76


- -7


+ 0*28


48


100


6-62


+ 0-44


+ 0-96


7-36


+ -63


+ 1-06


49


96


6-27


+ 009


+ 0-68


703


+ -20


+ 0-69


1860


64


4-76


-0-42


-019


6-46


- -88


-0-16



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(7. Ahbe on Terrestrial Temperature andJSolar Spots. 847

That the probable errors are on the whole very little dimin-
ished, is owing to the presence of a few large discordances ; on
the other hand, the small probable error of the coefficient of s
would indicate that it has a real existence^

As the daily 2 P. M. observation may be supposed to show
with specid clearness the direct heating power of the sun, I
have sought for a confirmation of the preceding results by
applying the same formula to the annual means of the tem-
peratures observed at this hour.

The annual mean temperature at 2 P. M. is given for each
year in the column /^ of tne accompanying table.

The arithmetical mean gives

M,= +6°-830zh0°-067
p. e. of one annual mean =db0°'489
The solution for the co-efficient of s gives

(^)=+7^-108(db0°100)-5X0°-O0801(dz0°-00221)
p. a of one annual mean =±0*465.

This result therefore corroborates the former in indicating a
decrease in the amount of heat received fi^om the sun during
the prevalence of spots — a result clearly in harmony with the
recent investigations into the nature of the solar photosphere.

The reality of the existence of the above coefficient of s will
be rendered more striking to the eye if the mean of several
years' observations is taken at the period of maximum and
minimum spot frequency.

It would be interesting to seek in the above residuals for
evidence of other temperature periods than that dependent on
the eleven year spot period. There are indeed plain indications
of such a period of about fifty or fifty -five years duration —
probablv iaentical with Wolfs fifty -six year period — but our
series of observations is not extended enough to justify any
exact conclusion.

If we acknowledge the probability of a connection between
planetary configurations and solar spots, then we are at once
led to make a direct connection between the former and the tem-
perature variations. Such an investigation I have begun and
the indications are that positive results will be attained, and
such as will demonstrate that the solar spots are but an imper-
fect index to the periodic changes in the solar radiation ; these
periodic changes being apparently more intimately and directly
connected wiSi the tides in the cool atmosphere surrounding
the solar photosphere. The results of this investigation will be
made known so soon as the recent observations on the Hohen-
peissenberg can be incorporated into the work.

Oindniiati, July 20, 1870.



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848 C, A. Toung on a method of determining the Levd-errcr.



Abt. XXXVL — On a new meAod of dekrmining the Level-error
of the axis ofameridtcm instrument; by C. A. YouNG, PkD.,
rrofessor, of Natural Philosophy and Astronomy in Dart-
mouth College.

[Read at the Troy meetiug of the Am. Association for the Advanoement of Sdeiioe ]

The inclination of the axis of a meridian instrument to a
horizontal plane has hitherto been measured by three diflFereni
methods : by the use of the spyit level ; by examining with a
collimating eye-piece the image of the wires as in namr-point
observations, the coUimation having been previously determined
either by reversal of the instrument or by collimators; and
lastlv by observing the transits of stars by reflection fix>m an
artincial horizon.

The first of these methods is by &r the most used, and with
portable instruments is sufficiently convenient Still it requires
a good deal of time, and, in the case of a lar^e instrument, of
hard work; and if there are sensible irre^larities upon the
pivots of the instrument it is a very troublesome operation to
ascertain and applv the necessary corrections.

The second and third methods are still more laborious : the
second gives the level error corresponding to but one single
position of the telescope, L e., with the telescope pointing down-
ward, and is therefore liable to a constant error depending
upon any malformation of the pivots which affects the instru-
ment in this particular position : the third method can be used
only when the air is perfectly stilL

The method I have to propose, allows the determination of
this error without any further labor than two readings of a
microscope, in any j>osition of the telescope^ and without that
uncomfortable climbing which is involvea m the use of tiie
striding level or nadir observations.

The annexed diagram illustrates the arrangement of the
apparatus, in which, however, no regard is paid to the relative
proportion of parts; the prism and mercurial horizon being
grossly exaggerated in size for the sake of distinctness.

The axis of the instrument is to be fitted up as a collimator
in the same manner already practised by Challis, Airy and
others. In place of cross-wires, however, ,the extremity A
should be provided with a plate of thin glass having a mmute
dot or circle engraved upon it, the plate being adjustable so
that this dot can be brought into the geometrical axis of rev-
olution and into the focus of the small object-glass which is
situated in the other pivot, O. A reading microscone, M, is
attached to the pier and provided with an ordinary collimating



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C A. Young on a method of determining the Levd-erroT. 840

eye-piece N, by wliich light can be thrown upon the dot through
the tube of the microecopa This enables us to measure the




vertical distance between the dot and its image formed by re-
flection in the manner to be described.

Opposite O is fixed a prism shaped like that of a camera
luciaa, which by two total reflections bends the light through a
right angle. Immediately below it is placed a mercurial horizon.
If an ordinary right angled prism were employed, producing
the bend by a single reflection, then any custurbance of the
prism would disturb twice as much the relation between the ray
passing from A to and that returning; but with a prism of
the form proposed this relation is independent of any small
changes in the position of the prism. Distortion of the prism,
which is hardly to be feared, could alone do any hann.

A prism of this form and mercurial horizon, Itvus comhinedj
form in effect a vertical plane rnvrror, whose verticaliiy is indepen-
dent of any small instability of the pier upon which it is mounted.

It is then easy to see that if the dot be accurately centered
and if the axis is level the image of the dot will exactly coincide
with the dot itself, provided that the reflecting angle of the
prism be exactly 186^. I^ however, the angle vary slightly
from this the image of the dot will fall above or below the dot
itself by a small amount, which will be constant, and can be
determined once for all by any one of several different methods.
Any deviation of the axis from horizontality will immedi-
ately be indicated by a change in this distance twice as laige
as the deviation itself, and may be accurateljr measured by the
microscope. Anjr inaccuracy in the centering of the dot is
immediately eliminated by taking two measurements in opposite
positions of the telescope.

The mercurial horizon employed should of course be so de-
vised as to be free from tremors as far as possibla The form
recently described by J. Hi Lane, of the U. S. Coast Survey, ap-
pears to leave little to be desired in this respect

There is no difficulty in arranging the apparatus so that the
ordinary illumination of the wires at the eye-piece of the teles-



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860 Kohlrauseh and Loomis — Influence of Temperattire

cope shall be eflFected by the light transmitted through the body
of the microscopa So arranged, the apparatus remains in con-
stant readiness for use, and, as before remarked, requires only
the labor of taking two microscope readings for each determin-
ation of level error, without involving any disturbance of the
setting of the instrument

I may add in closing, that this virtual mirror of constant incli-
nation to the horizon may easily find other applications, — as for
instance in determining the horizontal points of a vertical circle
where the object glass ol the instrument is not so large as to
require a too unwieldy and expensive prism.

Hanover, N. H. Aug. 1, 1870.



Art. XXXVn. — Influence of TempercUure on the modulus of
Elasticity of certain Metals ; by F. KoHLBAUSCH, Ph.D., and
Francis E. Loomis, Ph.D.

[Communioated in extracts to the Academy of Sciences, Gdttingen, Maj 7, 1870.]

The results obtained by Wertheim,* in his investigations re-
specting the influence of temperature on elasticity, have thus
fer generally served as a basis for calculation. It will be ob-
served in comparing these data, that for certain substances, espe-
cially for iron, the singular phenomenon manifests itself tnat
for aifferent temperatures the variations of the modulus under-
go a change of sign. From 0° C. to 100° the modulus increases,
and then from 1(X)° to 200° decreases. This increase is certain-
ly altogether contrary to what would naturally have been ex-
pected. Such a maximum, however, is still more remarkabla
In view, therefore, of the uncertaintv of the results of investi-
gations thus far made known, and the importance of an accu-
rate knowledge of the variations of the modulus of elasticity
for different temperatures in many of the finer measurements,
the present investigations were undertaken with a view if pos-
sible of obtaining more reliable results for some of the metals
of greatest practical utility. For practical purposes it would
suffice to determine the variations of elasticity within the lim-
its of the more ordinarily occurring temperatures. This was
partially accomplished by Kupffer, whose investigations we shall
refer to hereafter. Nevertheless in consequence of the results
obtained by Wertheim, it appeared of especial interest to deter-
mine again the variations in regard to their uniformity, as well
as in regard to a change of sign. The observations were ex-
tended therefore to high temperatures, in general from 90^ to
20° C, and in one case very nearly to 0°. Within these limits

* Pogg. Ann. Erg.. Band 2, a 61 ; Ann. de Chimie, 3<°« S., T. 12, p. 443.



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an the Elasticity of certain Metals. 851

the variations in the elasticity can b# determined from the ob-
servations with great accuracy. Since they show a remarkable
uniformit;jr, there can be no hesitation in assuming the result-
ing empirical formula as very nearly accurate, considerably be-
yond these limits.

It is scarcely necessary to observe that the investigations of
Wertheim have afforded the most valuable material for a knowl-
edge of the coefficient of elasticity. His method of observa-
tion, however, is little adapted to aSford a solution of the ques-
tion here under consideration. For Wertheim determined the
absolute moduli of elasticity by means of the dilatation of bars
and wires at different temperatures. The difficulties besetting
an absolute determination of the variations of quantities
amounting in all to only about l^"*™ are obvious. Tney were
especially serious for the hig her temperatures, since the imper-
fect heating apparatus of Wertheim could not be kept at a con-
stant temperature for any considerable period of time, and, in
consequence, the variations in length due to the fluctuations of
temperature, inevitablj^ exercised a serious influence on those
arising jfrom a change in elasticity. Wertheim himself desig-
nated these investigations as not rigorously accurate.* It would
unquestionably have been more rational to confine the absolute
determinations to ordinary temperatures, and to determine the
influence of the temperature by means of other methods which
here as in other cases, where it is a question merely of varia-
tions, are capable of a much greater sensibility. The influence
of the fluctuations of the temperature on the length of the ob-
ject will always occasion serious inconvenience in investigations
on dilatation.

All these difficulties disappear, however, and at the same
time the most accurate method of observation is obtained, by
employing for investigation the torsion elasticity, whose choice
is mrtner to be recommended from the fact that torsion is so
generally employed in measurements. If a wire is loaded with
a weight, ana set in vibration about its vertical axis, the recip-
rocal value of the square of the time of vibration affords a di-
rect measure for the coefficient of the torsion of the wire.
Since observations of the period of vibration are among the
most accurate known in physics, the variations of elasticity
may be thus determined with all the rigor desirable.

1. Apparatus and mode of cbservatum, — The following disposi-
tions were adopted for the practical application of this method.
(See fig. in about jV natural size). The vibrating body consisted



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