interior of the earth, also distinctly point out the seat from which this change proceeds. In many other cases the metamorphic process itself remains a mystery, and from the nature of the products alone do we conclude that such a metamorphic action has taken place.

Serpentine is generally believed to have been originally deposited as a sediment, and to have acquired its present compact crystalline character through the subsequent action of various chemical, or mechanical, agencies. It is known to be a hydrated silicate of magnesia with about equal parts of silica and magnesia, and contains 12 per cent. of water with varying proportions of iron, chromium manganese, alumina and lime, has a specific gravity of 2.7, and weighs about 169 lbs. to the cubic foot. It is found both in a soft and very compact state, of a waxy lustre, with many different shades of beautiful green which give it a mottled appearance like a serpent, hence the origin of its name "serpentine," or ophite. It is called "ranocchia" by the Italians, from the appearance it bears to the "frog," and, on account of its susceptibility to a high polish, is greatly valued as a marble for interior ornamental purposes, more than exterior, as it weathers rapidly. In Galway, Ireland, it is found in large quantities, and called "serpentinous marble," or "ophi-calcite." It is also to be found in other parts of the world, as in the Pyrenees, Alps of Dauphing, Mount St. Gothard, Italy, Sweden, Ural Mountains, Silesia, New South Wales, Savoy, Corsica, Cornwall, Scotland, and other places too numerous to mention; but in Canada the finest and most crystalline serpentine is to be found forming great belts of over 100 miles long and several thousand feet in breadth. There it associates with the dioretic, or volcanic, rocks, and is, according to Dr. Ells, without any doubt, "An alteration product of a dioretic rock rich in olivine." It is sometimes very difficult to distinguish the mineral constituents in many of the metamorphic rocks, but diorite is always considered to be composed chiefly of felspar and hornblende, which composition enters largely into the serpentines. Actinolite, tremolite, &c., and many other minerals, are sometimes found associating with it.

There are many valuable properties attributed to serpentine, and I am of opinion that the time is not far distant when it will be commercially considered an invaluable substance, and this on account of its refractory properties. I may also mention that it can be extensively used in the manufacture of crucibles, &c. Its soft and unctuous qualities (especially where it is found associated with "steatite," or "soapstone," which is often to be seen in large quantities) renders it easy to be worked, and, if reduced to a powder, could be moulded in bricks which the most intense heat will not affect. One of the chief properties it contains, and one which the serpentine of Lower Canada is so famous for, is the Asbestos, crysotile, or fibrous serpentine. This valuable and important mineral product is found in paying quantities only at certain points in the extensive serpentine reefs, and was first mined as an article of commerce in Canada in 1878, and has now become a regular and rapidly-developing industry.

On account of its incombustible and indestructible qualities, is extensively used in steam, hydraulic, and electrical machinery. It has been adopted by the Admiralty for engine packing, in Her Majesty's war-ships. It is spun into six-fold yarn, with a tensile strength of 40 lbs. and upwards, is manufactured into cloth, as clothing for firemen, and covering hose-pipes, in fire brigades, and also engine purposes, as well as drop-curtains, and general stage scenery, and is employed by the principal railway and steamship companies, collieries, ironworks and all classes of factories, and, in the manufacture of the new Asbestos