392 Miscellanies. 



goes on in geometrical progression, and being very slow exerts no 

 sensible influence on the duration of each oscillation. But the pres- 

 sure of the air, which does not alter the amplitude of the oscillations, 

 influences their duration, both because it is not the same in the sev- 

 eral horizontal sections, and because it changes in different parts of 

 the surface, in proportion to the condensation and dilatations which 

 accompany the motions of the air. M. Poisson obtains also, by an- 

 alytic theory, a result which accords in a satisfactory manner with 

 the direct experiments made on this subject by Captain Sabine. It 

 results from this that the correction relative to the reduction to a 

 vacuum ought to be increased one half, which gives rise to an aug- 

 mentation of To/o « 0^ i" the length of the single pendulum which 

 beats seconds. This length, estimated in parts of the metre, thus be- 

 comes for Paris, according to the experiments of Borda, 0™. 993856. 

 The expression of the gravity at the surface of the earth (measured 

 by double the space which it causes a body to pass through in a va- 

 cuum during the first second of its fall,) is then 9™.80897 ; and the 

 mass of the earth, as La Place determines it, must be also increased 

 about To/oo o» which rises it to as^Voe °f that of the sun. — Bib. 

 Univ. Avril, 1832. 



AGRICULTURE AND DOMESTIC ECONOMY. 



1 . On the CAiltivaiion of Beets and the mamifaciory of Sugar ; by M. 

 GiRARDiN. — In the year 1829—30, nearly two hundred sugar manu- 

 factories in France produced fromnine to ten millions of kilogrammes 

 of beet sugar, and it is believed that in 1830 — 1831, two hundred 

 and eighteen manufactories were in active operation. This business 

 has now become accessory to farming labor, and may be usefully 

 combined with the work of a farm of moderate size, on which from 

 seventy five to one hundred thousand kilogrammes of root can be 

 raised. It is advisable that neighboring farmers unite in the establish- 

 ment of a common manufactory, dividing the sugar and the remains of 

 the beet in proportion to the quantity of roots respectively furnished. 



The identity of the pure sugar of beet and of cane is now chem- 

 ically demonstrated. There remains however, in all sugars, a slight 

 mixture of foreign matters, and this furnishes the means of detecting 

 their origin. M. Dubrunfaut points out two means of testing: 1st, 

 Heat nitric acid at 25° on sugar until the red vapors cease, if the 

 liquor then presents a white precipitate, which settles at the bottom 



