396 Intelligence and Miscellaneous Articles. 



4. 1830, 1833, and 1836. The maximum seems to have occurred 

 in 1833, when as many as ten meteors were seen simultaneously. 

 " Dans la nuit du 11 au 12 decembre, on vit, a Parme une grande 

 quantite d'etoiles filantes de differentes grandeurs, qui se dirigeaient 

 presque toutes avec une grande vitesse vers le S.S.E. A 10 heures 

 et ■£, entre les seules constellations du Belier et du Taureau, on en 

 compta environ une dizaine." 



5. (Doubtful) 1861, 1862, and 1863. Maximum probably in 

 1862. The meteors at this return were far from being compa- 

 rable in numbers with the ancient displays. The shower, how- 

 ever, was distinctly observed. R. P. Greg, Esq., of Manchester, 

 England, says the period for December 10th-12th was, in 1862, 

 " exceedingly well defined " *. 



These dates indicate a period of about 29J years. Thus : 



901 to 930 1 period of 29-000 years. 



930 to 1571 22 periods of 29-136 years. 



1571 to 1833 9 periods of 29'1 1 1 years. 



1833 to 1862 1 period of 29000 years. 



III. The Meteors of October I5th-2lst. 

 The showers of the following years (see Quetelet's Catalogue) 

 belong to this epoch ; — 



1. 288. "Apparition en Chine." 



2. 1436 and 1439. In each year a remarkable apparition was 

 observed in China. 



3. 1743. (Quoted from Herrick, in Silliman's Journal for April 

 1841.) "A clear night, great shooting of stars between 9 and 10 

 o'clock, all shot from S.W. to N.E. [Qu. N.E. to S.W. ?] One like 

 a comet in the meridian very large, and like fire with a long broad 

 train after it which lasted several minutes ; after that was a train like 

 a row of thick small stars for twenty minutes together, which dipt N." 



4. 1798. "Brandes marque, a Goettingue, un grand nombre 

 d'etoiles filantes dans les observations simultanees qu'il fait avec 

 Benzenberg." 



These dates indicate a period of about 27 \ years : — 



288 to 1439 42 periods of 27*405 years each. 



1439 to 1743 11 „ 27-636 



1743 to 1798 2 „ 27*500 



If these periods are correct, it is a remarkable coincidence that the 

 aphelion distances of the meteoric rings of April 18th to 20th, 

 October 15th to 21st, November 14th, and December 11th to 13th, 

 as well as those of the comets 18661 and 18671 are all nearly 

 equal to the mean distance of Uranus. 



ON THE DIATHERMANCY OF A SERIES OF SUBSTANCES FOR 

 OBSCURE HEAT. BY DR. SCHULTZ-SELLACK. 



For the heat radiated by lampblack at 100° most substances are 

 entirely opaque, even in layers less than 1 millim. in thickness. But 

 a few substances are known which even in thicker layers transmit a 

 greater proportion of this heat — namely, rock-salt, fluor-spar, sul- 

 phur, sulphate of carbon, iodine in solution, sylvine. Some of these 

 * Silliman's Journal for May 1863, p. 461. 



