Natural-Historical Collections. 305° 
white ground are those of the golden oriole, (Oriolus galbula), the long-tailed: 
titmouse, (Parus caudatus), the nut-hatch, (Sitta), the creeper, (Certhia), of 
the chimney swallow, (Hirundo rustica), &c. The most part of these eggs with 
white grounds are hidden in well-covered nests. The mixed-coloured eggs, 
whose ground is not white, at least not a pure white, are those of the lark, 
(Alauda), the pipit, (Anthus), some wagtails, (Motacilla), and buntings, (#m- 
beriza) ; then the crows, (Corvus), shrikes, (Lanius), quails, (Perdia), and most 
of the singing birds, the colour of the interior of whose nests is in harmony with 
that of the eggs.—Werhandlungen der Gesellschaft naturforschender Freunde 
in Berlin, cah. 6. 1829. 

NATURAL-PHILOSOPHICAL COLLECTIONS. 
Extract from the Analysis of the Labours of the Imperial Academy of Sci- 
ences of Petersburg, for the years 1823-1826 ; by M. Fuss, perpetual Secretary. 
—THE academician, Zakharof, has read a memoir on the different degrees of 
heat and cold, in which he shows that the comparative table of different thermo- 
meters, published by the academy, contains some imperfections which he is en- 
abled to correct from the comparison of a number of observations on the degrees 
of temperature in different places, and of the results of experiments which he has 
made on many degrees of heat, such as it is customary to use in the Russion 
baths. This memoir goes further to prove that we cannot depend on the data 
furnished by different travellers on the winters of Siberia, and that it will be neces- 
sary to repeat the experiments with good spirit-of-wine thermometers. The same 
gentleman has occupied himself with bringing to a high degree of perfection two 
instruments of his own invention, which he communicated to the academy some 
years since, and which are, ananemometer and an apparatus for the ceration of sub- 
stances, which are with great difficulty fusible, by means of a certain mixture of 
hydrogen and oxygen gas. The construction of the anemometer is founded on 
the simple principle of forcing a solid intoa liquid ; and one may, with the assist- 
ance of this instrument, measure exactly the force of the wind acting on any sur- 
face. This foree is equal to the weight of the column of mercury which a cylin- 
drical or parallelopipedical body, plunged into this liquid, would cause to escape. 
By his second invention, M. Zakharof has sought to prevent the accidents which 
the mixture of the two gases often occasions, from its extreme inflammability. 
For this purpose, he has applied to his apparatus two valves, one of which shuts 
itself by its own weight, and the other by the pressure of the water, so that any 
communication between the condensed gas and the external air becomes impossi- 
ble. This same apparatus would also serve for the preparation of chemical ex- 
tracts, either in the large or small way, without any necessity on that account to 
change the scale of the apparatus. 
* M. Wisniewsky having observed and calculated, during his astronomical voy- 
age, some oocultations of the stars by the moon, has been able to furnish a more 
precise determination than we previously possessed of the geographical longitude 
of Moscow, Kasan, and Vologda. This labour was the subject of three of his 
memoirs—a fourth contained a proposal of a particular way of observing co- 
mets with the thread micrometer; this method, which permits of more exact 
observations, will be useful for the more precise determination of the orbits of 
comets. A fifth memoir, by our astronomer, was occupied by a new method of 
calculating the reduction of distance of the moon from the sun and the stars; a 
method which, requiring only theo perations of simple arithmetic, will essentially 
facilitate and abridge the calculation. 
M. Tarkhanoff has presented eight memoirs, in which he details his practical 
Jabours, as well in the observatory of the academy, as during his voyage. He 
VOL. I, 2Q | 
