European Asphalt.

The asphalts from Europe from which pavements are made are found in France, Germany, Switzerland, and in the island of Sicily. (In a pamphlet issued by a Greek professor in 1721 he says he discovered ten years before a mine of asphalt in the Val de Travers Canton, Neuchatel, Switzerland, similar to that existing in the valley of Siddim near Babylon.) Although somewhat widely separated, these asphalts are practically of the same nature, differing somewhat in amount of bitumen contained.

They are all bituminous limestones.

They occur in strata

of varying depths, from 6 to 23 feet in thickness, separated by impermeable beds of stone.

The theory of the formation is that at an early geological period bitumen must have been vaporized by extreme heat, that certain strata of the limestone were softer than others, and that this bituminous vapor was forced through and along the soft strata, as subterranean water follows any previous stratum confined by beds of clay or rock, and that fissures in the overlying

strata have allowed the vapor to pass to other strata above. In passing, the vapor impregnated the particles of the soft limestone to a greater or less extent, and the geological changes in the subsequent years produced the rock asphalt as it exists to-day. Fig. 1 illustrates this formation.

Its composition is almost entirely carbonate of lime and bitumen. To make a good pavement, the rock should contain from 9 to 11 per cent bitumen. While this amount may not be found in just the required proportions in nature, it can be obtained by mixing a rock that is rich in bitumen with one containing less, so that the compound shall contain the percentage desired.

Published analyses of the same mine differ considerably, perhaps on account of the solvents or methods used by the examining chemists, or possibly from an actual variation in samples from the same deposit.

The following are some analyses collected from various authorities, the bitumen and calcium carbonate only being considered:

In the State of Vera Cruz, Mexico, there are fifteen separate deposits of asphalt; that is, there are fifteen places where asphalt is found at the surface.

Analyses of samples from the different localities show the material to be identical, and it is supposed that they are all connected underground, and supplied from the same source.

These deposits as found vary in width from 150 to 200 feet, and in length from 400 to 600 feet. The overflow from them is very great. In several instances it forms a bed between 50 and 60 feet wide and one or two miles long.

The largest deposit is known as Lake Chapapota, or in the language of the natives, Laguna Chapapota ("Lake of Asphalt "). This lake is of irregular shape and of unknown depth. Its sides are nearly perpendicular, as no bottom has been found by sounding three or four feet from the edge.

Large quantities of the material have overflowed in every direction, and whatever amount has yet been taken from the lake, the overflow still continues uninterruptedly. It has been estimated that 1000 tons per month could be taken continually from the lake without in the least lowering its surface. The amount in sight has been calculated at about 300,000 tons.

Pipes have been sunk to a depth of 500 feet near these deposits which have passed through vast beds of asphalt. From these pipes asphaltic oil is constantly flowing.

An analysis of nine different samples of this asphalt in a crude state gave results as follows:

Bitumen.....

Wood, insects, shells,

TABLE NO. 11.

84.04 82.74 86.34 83.70 87.94 86.11 90.14 87.54

and leaves.... 4.86 4.76 2.96 1.96 2.36 3.12 2.36 2.56 Matter volatile at 450° 11.10 12.50 10.70 14.70 9.70 10.77 7.50 9.90

The refined product analyzed:

Bitumen

Silt and lime.

Per cent.
99.47
.53

100.00

The above analyses were made by Julius C. Schubert of New

York, who recommended for a paving mixture:

An examination of another sample was made by Marriner & Hoskins of Chicago. The asphalt was heated until all the water was expelled, and then the temperature was gradually raised till the thermometer indicated 400° F. and maintained there for nine hours. The fluid was then poured from the sediment, of which there was but little, and analyzed:

at 60° it was tough, compressible, and flexible;

at 75° it was softer and more flexible;

at 100° it had the consistency of putty; beginning to flow;

at 300° there was no flash.

It is claimed for this asphalt that it requires the addition of no flux whatever to prepare the asphaltic cement, and that on this account, and because of its greater purity, it will resist successfully the action of air and water. Also it is said that a kettle of this material was heated to 625° F. for ten hours without its being damaged in the least. This last fact would avoid the liability to injury on account of overheated sand, which often occurs in using the asphalts at present in general use.

Bermudez Asphalt.

In the State of Bermudez in the northern part of Venezuela and about one hundred miles from the island of Trinidad is another large deposit of asphalt. It was discovered by the early explorers of this region, but no attempt was made to develop it or put it on the market until within the last few years. It is generally called a lake, and is situated near the San Juan River, about 18 miles from where it empties into the Gulf of Paria.

The river is navigable for vessels drawing 18 feet of water to this point, at which is situated the shipping station of the New York and Bermudez Company, which owns and controls the property.

The lake is about 5 miles from the point of shipment. It includes an area of some 1200 or 1500 acres and is covered with quite a heavy growth of grass and bushes. Its depth has never been determined, as in sounding it has never been possible to find bottom, and the supply seems to be inexhaustible. In hardness it varies from the material that is in a soft fluid condition to the hard brittle glance pitch, but the greater part is of a medium grade suitable for commerce.

Through the lake runs a so-called stream of soft material, varying in width from 100 to 400 feet, seemingly in a state of continued motion.

Over all the surface except this stream one can walk with safety at all times of the day, but on the stream itself it is not safe to venture after the sun is a few hours high, as the heat soon renders it so soft that a man will sink into it to quite a considerable distance.

It is said that a workman dug day after day for two years in a hole about 6 feet in diameter, and the amount removed in the daytime would be replaced at night, so that the hole was no larger at the end of two years than at the beginning.

A narrow-gauge railroad, operated by steam, connects the lake with the shipping-point. The surface of the asphalt not being firm enough to sustain the weight of the steam-cars, a portable track is laid out on the lake upon which cars are operated by hand. The pitch is dumped from these hand-cars into those on the main line, which in turn are drawn down to and out upon the dock, when they are unloaded into vessels lying alongside.

The first pavement laid with this material was on Woodward Avenue, Detroit, in 1892. Since then, however, it has come into general use in the different cities of the country. The crude material is refined at South Amboy, N. J.

When refined, the asphalt contains of bitumen 97.22 per cent, mineral matter 1.50, and organic matter 1.28. The bitumen is