270 Magnetism of Violet Light. 
netizante del lembo estremo del raggio violetto,”’ &c. &c. not 
published. The red ray of the spectrum does not magnetize, 
nor the light of combustible bodies, inflamed. The violet light 
of the lunar beam has given in twelve hours magnetic properties 
more decisive than the solar red in seven hours anda half. The 
duration of the experiments in December 1812, and February, 
March and April 1813, with violet light, varied from 23 to 120 
minutes, nor seemed to have any relation to the range of the ba- 
rometer, thermometer, or hygrometer; for on lst of March 1813, 
when the duration was only 23’, Reaumur’s thermometer was7*25, 
barometer 282,20, and the hygrometer of Retz 41:65; and on 
Ath of April 1813, when 120’ were required to produce the mag- 
netic effect, the thermometer was 11°70, barometer 28-0,50, 
and hygrometer of Retz 28-90, but this last was in a cloudy sky 
and moist at intervals; though on 23d of March while the ther-- 
mometer was 10°15, barometer 28-2,15, and hygrometer of R. 
31°25, the duration of the experiment was 39’, and the mag- 
netism most intense. Tor the three preceding days the sky had 
been very variable. 
Experiments were made on the chemical rays of the spec- 
trum on the 15th, 16th, and 18th of April 1813. On the 15th, 
with a cloudy sky, and hygrometer of R. at 32°25, weak’ mag- 
netic signs were manifested in 30’. On the 16th of April, a cloudy 
sky, hygrometer 28-85, the magnetism was intense in 70 mi- 
nutes, and on the 18th, hygrometer 29:10, also intense, in 60’. 
On the 27th, 28th and 29th of March and Ist of April 1843, ex- 
periments were made on the red light of the spectrum, but no 
magnetic signs were exhibited. On the 2d of April a feeble and 
equivocal repulsion was shown. None were manifested with two 
experiments on green light: in one however slight signs were 
given, but the magnetism was feeble and incomplete. On the 
14th of April with undecomposed light a little magnetism was 
acquired in 120’. In the first experiment with lunar violet light 
no magnetic effect was produced; in the second, there was an 
indecisive tendency to the magnetic meridian: the same was 
shown in the third, fourth and fifth experiments which succeeded ; 
and in the two last a superior attraction. On the 15th, 16th, 
and 19th of April, with the red ray there was no effect produced 
in 60 minutes; but with red light on the 21st of April and 16th 
and 20th of May, an indecisive tendency to the magnetic plane 
was discovered in 90’, 30’, and 90’. Experiments made on the 
10th, 11th and 12th of May with the violet light of the flame of 
olive oil gave no magnetic signs in 240’, 120’, and 120’.—Dr. M. 
told me he did not use a reflector for the lamp in this experiment. 
We cannot therefore withhold what the Professor claims as 
confirmed, page 31, “ le nuove sperienze che ho avuto l’onore di’ 
esporvi 
