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Astronomy and Meteorology. 135 
3. On the Algebraical and numerical theory of errors of observations 
and the combination of observations. By Grorce Bippew. Ary, M.A., 
Astronomer Royal of Great Britain. London, 1861. 12mo, 120 pages. 
se 
The result of Mr, Airy’s investigation is that the observations should be 
combined by multiplying each measure by a number which is called the 
“combination weight ;” that we should add together these products of 
Measures by Spel ERROR and divide the sum by the sum of com- 
bination weights. With respect to that combination-weight which is most 
advantageous, Mr. Airy concludes that that combination is best which 
gives a result whose probable error is the smallest possible. It is then ne- 
cessary to determine the value of the probable error in each of the obser- 
vations, Frequently this cannot be done by any simple rule, because the 
observations are not all alike. The determination of the value of this 
probable error must rest very much with the judgment of the observer, 
t. Airy adds “the reader must not be startled at our referring these 
decisions to his judgment, without material assistance from the calculus, 
The calculus is, after all, a mere tool by which the decisions of the mind 
are worked out with accuracy, but which must be directed by the mind.” 
METEoroLocy-— 
[We present herewith abstracts of several important papers by Prof. 
Haidinger of Vienna on the subject of meteoric falls in which will be 
cund many new and important views both physical and mineralogical 
Ser., vol. xv, page 15). W ; 
Imp. Acad. of Vienna of April 14th, 1859, ee the Latin document _ 
n 
Cabinet of minerals at Vienna. At the meeting of Febr. 3d, 1860, he 
Presented a third document, which had been discovered in the arch- 
¢p'scopal library at Agram, describing the phenomenon as pg tee vtid 
peca near Warasdin, 174 miles north, a little towards East of ina. 
* Der Meteoreisenfall von Hraschina bet Agram am 26 Mai, 1751, von W 
Hatwinerr, Wien, 1859, mit 1 chromolithogr. Taj. 
