by Barkham Burroughs
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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.
How Many Tons of Coal a Large Steamship Consumes in a Day.--"Ocean steamers are large consumers of coal. The Orient line, with their fleet of ships running to Australia every two weeks, may be mentioned. The steamship Austral went from London to Sydney in thirty-five days, and consumed on the voyage 3,641 tons of coal; Her coal bunkers hold 2,750 tons. The steamship Oregon consumes over 330 tons per day on her passage from Liverpool to New York; her bunkers will hold nearly 4,000 tons. The Stirling Castle last year brought home in one cargo 2,200 tons of tea, and consumed 2,800 tons of coal in doing so. Immense stocks of coal are kept at various coaling stations. St. Vincent, Madeira, Port Said, Singapore and others; the reserve at the latter place is about 20,000 tons. It is remarkable with what rapidity these steamers are coaled; for instance, the Orient steamship last year took in over 1,100 tons at Port Said in five hours."
What a Man Eats.--A French statistician has just ascertained that a human being of either sex who is a moderate eater and who lives to be 70 years old consumes during his life a quantity of food which would fill twenty ordinary railway baggage cars. A "good eater," however, may require as many as thirty.
An Australian Railway Viaduct.--The Werribee Viaduct, in the colony of Victoria, is the longest work of the kind in Australia. The structure consists of lattice-girder work. It is 1,290 feet in length, and runs to a height of 125 feet above the level of the Werribee river. The viaduct has fifteen spans each of 60 feet, and thirteen spans of 30 feet. The total cost of the bridge was £600,000.
The Sharpening of Tools.--Instead of oil, which thickens and smears the stone, a mixture of glycerine and spirit is recommended. The proportions of the composition vary according to the class of tool to be sharpened. One with a relatively large surface is best sharpened with a clear fluid, three parts of glycerine being mixed with
