Iviii 



at the time: afterwards Plana resumed it alone, developed it more 

 completely, and published it in 1832, under the title " Theorie du 

 Mouvement de la Lune," in three volumes quarto, a work which 

 forms an epoch in the history of astronomy. In 1820 they published 

 a joint memoir in reply to some objections to their theory raised by 

 Laplace and another on the lunar equation, having for its argument 

 twice the difference between the longitude of the node and that of 

 the perigee. Carlini next undertook the construction of lunar 

 tables. These have been used up to the present time in computing 

 the places of the moon for the Effemeridi di Milano. He afterwards 

 investigated various points of the lunar theory, especially the 

 remarkable inequality of the moon's mean motion, indicated by a 

 comparison of ancient and modern observations, and produced, as 

 Hansen proved in 1847, by the disturbing action of Venus. Of his 

 " Algoritmo del calcolo delle perturbazioni lunari," intended as the 

 commencement of a complete lunar theory, only the first chapter ap- 

 peared in the 5th volume of the memoirs of the Istituto Lombardo. 



Carlini' s principal contributions to practical astronomy are: 

 "Tables of astronomical refraction" (1807); "Computation of 

 occultation of stars by the moon" (1808) ; " Tables for the reduc- 

 tion of circummeridian altitudes," (1809) ; "Tables for calculating 

 the coefficient of the square of the time in the precession of stars " 

 (1819). He invented a method of finding the time and latitude by 

 means of a telescope provided with a level and a micrometer, and 

 applied it in Spain, where he went by order of the Government to 

 observe the eclipse of the sun on the 18th of July, 1860. 



Between 1821 and 1827 Carlini assisted in the measurement of 

 the Italian portion of an arc of longitude extending from Bordeaux 

 to the Adriatic. He made the requisite astronomical observations 

 on the summit of Mont Colombier ; determined the length of the 

 seconds' pendulum on Mont Cenis ; observed from Parma the gun- 

 powder signals fired on Monte Cimone, and from Milan those fired 

 on the summit of Monte Baldo. He also determined anew, with 

 the aid of better instruments and improved methods of calculation, 

 the latitudes of Mondovi and Andrate, the extremities of the arc 

 measured by Beccaria. He found the sum of the deviations of the 

 plumb-line to be about 48", and thus confirmed the accuracy of 

 Beccaria' s observations. 



