Popular Science Monthly
��267
��Applying Hot Road Material
TO be impervious to water and to re- sist wear to the greatest possible degree, roadways must be impregnated with hot tar or some similar material. This condition demands vehicles which combine the necessary distributing ap- paratus with a plant for heating the road material.
The truck illustrated herewith is of five tons capacity and is one of three re- cently installed in Baltimore, Md. The truck has a four cylinder gasoline motor, and this also operates a powerful air compressor with which the hot liquid is forced out on the roadway.
��With the Forty-Niners
THE historically important discovery of gold in California was made in January, 1848, at John Sutter's mill on South Fork of American River near Co- loma. a point only ten or fifteen miles southeast of the town of Auburn. From 1850 to 1853 the greatest yield was de- rived from the gravels, and the largest annual output for this period was more than sixty-five million dollars in 1852. There was some reaction in 1854, due to previous wild speculation, but a produc- tion of about fifty million dollars a year, chiefly from placer mines, was main- tained up to the year 1861.
���To obtain the best results, the tar to be used in making roads must be sprayed while hot.
A great tank truck has been built, which has a small boiler on the rear of the chassis to
keep the material at the desired temperature
��The material within the tank is main- tained in a liquid state with the aid of a small flash-steam boiler, which is mounted at the back of the chassis and which may be fired with either kerosene or gasoline. From this generator, super- heated steam is led through the material in a continuous flow by means of pipe- coils.
THE most remarkable gold and silver beetles are to be found in Central America. Some have the appearance of burnished gold while the others are like silver. They are worth $35 apiece.
��At first the gold was won chiefly from the gravels along the present streams. Those who first got possession of the rich bars on American. Yuba, Feather, and Stanislaus rivers and some of the smaller streams in the heart of the gold region, made at times from one thousand to five thousand dollars a day. In 1848 five hundred to seven lumdrcd and fifty dollars a day was not unusual luck ; but, on the other hand, the income of the great majority of miners was far less than that of men who seriously de- voted themselves to trade or even to common labor.
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