Miscellanies. 195 



With respect to the days of the first and last quarter, the changes 

 on these were 96, which bring them nearly to the condition of com- 

 mon days. 



It is thus shewn from the tables, that the chance of a change at 

 new and full moon, compared with the chance on ordinary days is 

 as 125 to 117, and that the chance on the day following these two 

 phases, compared with the common days is as 154 to 117. 



Upon the whole therefore, this examination lends some support to 

 the vulgar opinion of the influence of new and full moon, but none 

 whatever to any especial influence of the first and third quarters. 



With respect to barometical pressure, it is ascertained that out of 

 the 1458 changes of weather there were in 1073 cases a corres- 

 ponding rise or fall of the barometer, according as the change was 

 from rain to fair, or the contrary. This is nearly as 3 to 4. Of the 

 385 false indications of the barometer 1S2 were on a change from 

 rain to clear, and 203 on a change from clear to rain. Finally, of 

 the 385 anomalies of the barometer, 17 were at full moon, and 10 

 only at new moon. — Bib. Univ. Fev. 1834. 



25 Artificial ultra-marine. — M. Guimet in a letter to Gay Lussac 

 dated Lyons, May 31, 1831, informs him that he had been for two 

 years directing his attention to the improvement of the fabrication of 

 this article, with a view especially of rendering it cheaper, — that ex- 

 perience had proved, that it might supersede with advantage and 

 economy, not only the blue of cobalt in painting, but also the azure 

 or colored glass (smalt ?) used in such enormous quantities in blueing 

 paper, linen, calico, muslin, he. and with which Germany supplies al- 

 most all Europe. As to painting he never had any doubt of the re- 

 sult; but with respect to paper painting, &c. he had despaired on 

 account of the low price of cobalt, the best quality of which sells 

 for 2 yVo francs or 3 francs per pound, while the best quality of the 

 ultra-marine, that which is refined for the use of painters is 60 francs, 

 and that of the second quality is 20 francs per pound. 



A trial however, of the ultra-marine having been made in paper 

 staining, and found to answer extremely well, IM. Guimet distributed 

 200 pounds of his article among the paper makers in the vicinity of 

 Lyons at 20 francs a pound, it was proved that one pound of the ul- 

 tra-marine, on account of its intensity and extreme division, went as 

 far in coloring as ten pounds of the finest and most beautiful cobalt. 

 In consequence of this remarkable success, the demand for the arti- 



