LIGHT OF THE SUN.—­A photometric experiment of Huygens, resumed by Wollaston, a short time before his death, teaches us that 20,000 stars the same size as Sirius, the most brilliant in the firmament, would need to be agglomerated to shed upon our globe a light equal to that of the sun.

Land Cultivation in Japan.—­The entire arable land of the Japanese empire is officially put at only 11,215,000 acres; but it is so fertile and thoroughly cultivated that it feeds a population of 37,000,000, about that of France.  Rice is one of the principal crops, and of this some 200,000,000 bushels are raised annually.

Old London Bridge.—­As early as the year 978 there was a wooden bridge where London bridge now stands.  This was replaced by another in 1014, and another in 1209.  The present London bridge was erected in 1831, and may be considered the oldest existing bridge over the river.

The Shortest Method of Removing Silver from Plated Ware Before Replating.—­Dip the article in nitric acid; this will remove the silver.

A Formula for White Metal.—­Copper, 69.8 parts; nickel, 19.8 parts; zinc, 5.5 parts; cadmium, 4.7 parts.  It takes a fine polish.

Curiosities of Metal Working.—­At a recent meeting of scientific men, a speaker produced an anklet worn by East Indian women.  This is a flat curb chain about one inch broad, with the links very close, and weighing about ten or twelve ounces.  It is composed of a species of brass composed of copper and lead, without any trace of silver, zinc, or tin.  Such anklets are sold for a few pence, and they are cast all at once, complete as an endless chain.  The links show no sign of having been united in any way.  How it was possible to produce such a casting as this passed his comprehension, and he hoped that some one who had seen them made would explain the nature of the process.  From the East much that was curious in metallurgical art came.  Cast-iron was, he believed, first made purposely in China.  It was, however, frequently produced unintentionally, when wrought-iron was made direct from the ore in little furnaces about as big as a chimney-pot.  It was found among the cinders and ash of the [Transcriber’s Note:  The original text reads ‘coarcoal’] charcoal-fire in grains or globules, which were not only like shot, but were actually used as shot by the natives.  He showed what he believed was the only specimen in England of this cast-iron, in a bottle.  He next referred to the celebrated Damascene blades of Indian swords, and explained that these blades were an intimate mixture of wrought-iron and hard steel, which must have required great skill, time and patience for its production.  One [Transcriber’s Note:  The original text reads ‘patern’] pattern, in particular, known as “Mary’s Ladder,” showed wonderful finish and accuracy.  Concerning the tempering of these blades little was known; but it was stated that it was affected by a long-continued hammering, or rather tapping, of the blade while cold.