constantly permeated by water, which dissolves all the sulphate. This water is then evaporated, and the copperas crystalized out.

Sulphur may be formed by roasting the ore. It is not so economical a method of preparing sulphur as the obtaining it from volcanic regions; but sometimes it becomes a matter of necessity to manufacture it from pyrites, as it is now in the Southern States. In case we should be at war with Great Britain, our supplies from abroad might be cut off and we be obliged to manufacture it from pyrites. In such a case, Maine will afford an abundance of material for the manufacture of sulphur. The chemist, in his report, will speak further upon this subject; also upon the manufacture of saltpetre.

Alum is formed partly from the pyrites and partly from the rock. The sulphur of the pyrites becoming sulphuric acid unites with the alumina and potassa of the slate, forming a double sulphate. It is only occasionally that all these substances are present, but very easily performed experiments will decide the question. The opportunities for the manufacture of alum in the State are very great.

The carbonate of soda can be formed by the combined action of the decomposition of pyrites with carbonate of lime and sea water. First produce the copperas; then mix it with sea water, when sulphate of soda or Glauber salt will be formed. This may be crystalized out and then decomposed by carbonate of lime, with the aid of heat, when carbonate of soda will be the result. Gypsum will also be formed, but it is not of sufficient value to be preserved. Carbonate of soda is used in the manufacture of glass and soap.

Engineering and Architecture.

We can easily, under this head, treat of the materials used for both engineering and architecture. The engineer must locate railroads, turnpikes, canals, excavate tunnels, construct embankments, quays and bridges. The architect must select the sites for dwellings; and both must choose suitable materials for their works. Both must consider the locations of their works, and the materials to be used in construction. Geology can assist both.

In the construction of all kinds of roads, attention must be paid mostly to the character of the loose materials, whether the road shall run over clay, sand or gravel. A little knowledge of geology, particularly of theoretical geology, may show the engineer a great superiority of one route over another. For example, he may con

struct a road along an alluvial valley lined with terraces. One terrace is uniformly composed of sand or loam; another of clay, and the third of gravel. In fact, this is generally the character of the three lowest terraces as has already been stated. Now if the engineer could only know this before the road is built, it would be of great service to him. The same principle will apply to the selection of sites for dwellings. Many buildings are ruined by want of discretion in the choice of the site. In this case, the character of the underlying rocks must often be known.

In cutting through rocks, a little practical knowledge of them will often save immense labor; for example, in the construction of a tunnel. Rocks excavate very easily, when the cut is made through the broad face of the strata. To cut through the edges of strata, requires double the labor. A geologist, too, can judge of the nature of the rock in the interior of the hill or mountain tunneled. If for any reason the rock in the interior is a trap rock of a certain character, the engineer must calculate upon a task as difficult as to blast iron. The principles of geology are also required in the location of Artesian wells.

These remarks have been thrown out at random, as it would be impossible for the geologist of a State to point out the advantage of one specific location over another in a report. We only argue that if the principles of geology were well understood by engineers and architects, their labors would be rendered much easier.

When we come to speak of the materials to be used for building purposes, we can dwell particularly upon the character of the best materials. For most common purposes men are obliged to use such materials as are the most accessible without regard to quality. In connection with valuable materials for building purposes, we shall speak also of several articles of a miscellaneous character. We shall speak of granite, gneiss, freestone and other building materials; then of flagging and roofing materials; next of ornamental articles such as marble and serpentine, of lime, cement, glass sand, clay for bricks, honestones, etc. We must necessarily be exceedingly brief.

Granite and Gneiss.

Granite and gneiss may be connected together in this notice, since both answer the same purpose, and are called by the same name among workmen. Their value for building materials need

not be dwelt upon, as their merits are well known. We will only speak of certain localities where they are or might be quarried to advantage.

There is no State in the whole Union where the facilities for quarrying and transporting granite are so great as in Maine. Quarries line fully half of her seaboard, so that the very cheapest mode of transportation is at hand. Add to this, that south of Cape Cod as far as Mexico, the coast is entirely alluvial, and that for a great distance inland, so that the seaboard towns can procure their granite from Maine cheaper than from their own States, if the rock occurs there. Whatever be the political relations of the States, the supply of granite must come from the north.

Granite, syenite and gneiss (while all answer the same purpose) are found in inexhaustible quantity and of proper character for building materials in Kennebunk, Biddeford, York, Newfield, Waterford, Phipsburg, Edgecomb, Wiscasset, Brunswick, Hallowell, Augusta, Friendship, St. George, most of the islands of Knox and Lincoln counties, Brooksville, Bluehill, Frankfort, Mt. Waldo, etc., Sedgwick, Sullivan, Mount Desert, Gouldsborough, Calais, and all the immense granite regions of Hancock and Washington counties, the Katahdin region, and a hundred other localities, for a general notice of which we would refer to our remarks on the distribution of gneiss, granite and syenite. There is enough granite in the State of Maine to build all the cities in the world. So great is the amount of good granite in the State that we cannot have time more than to allude to the quarries that have been known for the longest time, although the quality of the stone in them is no better than in a hundred other cases not mentioned. We are not able to give the present statistics of any of the quarries.

The best known localities are along the coast. In Kennebunk, there are the United States, the Ocean, the New York and Kennebunk quarries, and others. The granite contains very many crystals of black mica, thus giving it a dark color. Its feldspar is pure white and glassy. The quartz is in very small amount. The stone procured in Kennebunk is largely sold in New York.

The Hallowell granites are universally known. The granite is taken from a ridge running north-east and south-west, elevated about 400 feet above the Kennebec river. The rock is really. gneiss. Feldspar is the principal ingredient in this rock. It is

white, while the mica is silvery gray. It is fine grained an 1 looks beautifully when hammered smooth. Blocks can be obtained here. weighing more than a hundred tons.

The rock in the New Meadows Quarry in Brunswick is like that in Hallowell. A few minute red garnets are scattered through the mass, which add to rather than detract from its beauty. The locality is at Howard's Point, and is capable of furnishing a large supply of building stone. The Phipsburg stone is similar to the Brunswick and Hallowell rocks.

The Wiscasset and Edgecomb granites are properly in the form of beds, though of great size. The latter is dark colored, containing a considerable black mica, and has been largely shipped to New Orleans.

The coast of Lincoln county and the islands adjacent abound with granite. A great deal of granite from Seal Harbor has been transported to New York, and was used also to construct Fortress Monroe in Virginia. The State own several granite quarries in this vicinity.

Mt. Waldo, Mosquito Mountain, and Treat's Mountain on Penobscot bay, are composed of most excellent granite. The first named is the largest, and is a huge pyramid of granite. The granite is of the porphyritic variety, splits well, may be wrought into almost any shape, and will appear well in any kind of building. The quarries were opened upon this mountain in 1836. The rock at the other mountains on the Penobscot yield granite of the first quality. Several companies have been quarrying granite in Bluehill to advantage. The rock is rather coarse grained but is very handsome when hammered. The granite in Brooksville is of a similar character. Immense granite quarries are worked in Sullivan; viz., Stimpson's and the Mount Washington quarries. We think none of the quarries now worked can furnish stone superior to that in the immense granite ranges of the two south-east counties of the State. We would say more about the granite quarries, did they not loudly speak for themselves. They constitute an immense source of wealth for the State.

Freestone, etc. The Devonian sandstones of Washington county will afford in some localities very good freestone. A quarry of this rock has been worked in Perry, about half a mile from the post office, by the St. Croix Coal and Freestone Company. The stone is of good quality, like the famous Portland freestone of Connecticut. Other

localities will be found in the vicinity. The red sandstone of Machiasport may yield a stone that will be superior to the ordinary loose freestone, because it will resist decomposition for a longer period.

It is curious that the popular building materials used in Europe and America should vary so much. With us, granite is very popular, though not exclusively used. There the freestones and oolite rocks are the common materials used. They are not as enduring as our granite, still many of them are as firm now as centuries ago when they left the quarries.

The trap and porphyritic rocks of the south-east counties are often suitable for building materials. With some, they are very popular.

It is an important and difficult point to ascertain how long a rock will resist disintegration. When buildings have been erected for many centuries, as in the old world, this point can readily be determined. But in this country, where all our edifices have been constructed recently, we must resort to other means. The mineral composition will aid us somewhat. The more perfectly crystalline the rock is, the more enduring it will prove in general. A better method is to examine the ledges where they have been exposed to atmospheric agencies for ages, and observe the amount of wear and decomposition. Some artificial chemical methods may also be used.

Flagging Stones and Roofing Slate.

Mica schist adapted for flagging stones abounds in the State. At Phipsburg, near Small Point Harbor, is one locality; and there are others in the mica schist in Winthrop, Acton and Lebanon. The Phipsburg schists are very beautiful, though not as strong as desirable. Some of the fine sandstones in the northern part of the State would do better service; but they are too remote at present from the market. Other localities furnish flagging stones which are used locally to a great extent.

Roofing slate occurs in Maine of the best quality, and like the granite, is inexhaustible in amount. Quarries of it may be worked both tolerably near the salt water, and far in the interior. Discoveries of new slate quarries will constantly be made, and the demands for the slate will be constantly increasing, as it is used for many purposes besides roofing.