Some of the figures given in tests 3 and 3A are difficult to understand. Working on the same material, wrought iron, and under the same conditions, Hastings corundum in one case is said to grind away 3 oz. in 3 hours, while in another case it is said to grind away 4 oz. in 2 hours. In another case Hastings is said to grind away 1 oz. in 1 hour, while in another experiment it is found to grind away 23 oz. in the same length of time. It will be noted that this latter amount is greater than the amount ground away by N. Carolina in the same length of time.

4. Comparative Test of Hastings Corundum and North Carolina Corundum on Cast Steel :

Test 4 between wheels of Ontario and North Carolina corundum, made on cast steel and maintained for three hours, shows that the former ground off one ounce more than the latter, or an excess of 15 per cent. Test 4A between wheels of Ontario corundum and carborundum, made also on cast steel and maintained for eight hours, shows that the former ground off 19 oz. and the latter 5 oz., being an excess of 13 oz. or 262 per cent. in favor of Ontario corundum. In steel plow works abrasive wheels are largely used, and it is probably the case now that as much of steel as of iron undergoes abrasive treatment in foundries and machine shops.

Testimony from Other Sources.

Smaller samples of grain corundum than that furnished the Hart Emery Co. have been supplied different companies Manufac- both in the United States and

Dealers and

turers. Europe. In no case has the material been condemned. The following quotation from a letter recently received by the Director of the Bureau of Mines from a London, England, firm to whom some pounds of the grain had been sent voices the opinion of others who have examined the material: "We consider the mineral to be good, and hope some company will be formed for the exploitaton of these corundum deposits; in which case we shall be glad to hear from you again.

"19

19 Since the above was written an additional quantity of corundum-bearing rock has been treated under the direction of Mr. R. Instant in the mill of the Kingston School of Mining. This rock was obtained at the Robillard property in the township of Raglan and weighed 8 tons 650 lb. The method followed in its treatment was the same as that used by Prof. De Kalb and described by him in the Report of the Bureau for 1897. The rock was first broken in a Blake crusher to such a size that the larger fragments had a diameter of about one inch. It was then passed through rolls, after which treatment the larger pieces of rock had a maximum diameter of one-quarter inch. After coming from the rolls the rock matter was sized by means of sieves. It was then treated by the Hartz jig, which through the agency of water separated the minerals of low specific gravity (chiefly felspar and mica) from those of higher specific gravity. These latter were corundum and magnetic iron ore. After coming from the jig the mixture of these two minerals was dried and then the magnetite was freed from the corundum by means of the magnetic separator.

The 8 tons 650 lb. of rock gave by this treatment, after recrushing some of the No. 10 and 12

This equals 14.22 per cent. of the rock treated. In addition there were various small amounts of corundum abstracted as samples at different times, which would aggregate probably 50 lb. Moreover the dust or finest material coming from the crushers was not jigged. This material it was estimated contained about 100 lb. of corundum in a fine state of division. In addition to this some corundum was lost in the tailings from the jigs.

The result of this test agrees with that obtained by Prof. De Kalb on rock from the township of Carlow, which adjoins Raglan on the west. In that test the amount of corundum extracted in the mill was equal to 14.67 per cent. of the rock treated. The rock from both townships was similar in appearance, being coarse grained and for the most part pink in color, forming what is known as syenite-pegmatite

The specific gravities of the various numbers of the grain corundum extracted in the mill test from the Raglan rock were determined. Those of No. 16, 30, 40 and 50 were found to be 3.952, 3.953, 3.976 and 3.945 respectively. Since the specific gravity of pure corundum ranges from 3.95 to 4.10 it will be seen that the product from the mill run of the Raglan rock is practically free from foreign

matter.

The X-ray photographs which accompany this report show the form and actual size of the grainof corundum of the different numbers. They mores over show that it is possible by photographing samples of commercial corundum in this way to determine their degree of purity, since corundum grains themselves are not so impervious to the

rays as are silicates such as felspar, garnet, chlorite and mica, which are frequently associated with this mineral or are used to adulterate it in com

merce.

A dozen or more samples of the grain corundum, each weighing upwards of 100 pounds, produced from the Raglan rocks, were submitted to leading manufacturers of abrasive goods in America and Europe, by whom they were tested and pronounced suitable for use both in vitrified wheels and in those which are cemented together according to the ordinary binding formulas. The Prescott Emery Wheel Co., of Prescott, Ont, report: "For light work for tools the corundum presents a fine cutting surface. If these wheels are too soft or too hard we can easily remedy that by a variance in our formula." The Sterling Emery Wheel Mfg. Co. of Tiffin, Ohio, say: "The samples look very nice and the corundum works well. Please advise us in what quantities you expect to get it out." The Chicago Wheel and Mfg. Co. say that the corundum in the wheels manufactured by them looks well and they are sure the wheels will do good work. The Norton Emery Wheel Co. of Worcester, Mass., state that the result of their tests on the grain corundum to see whether it would work up satisfactorily according to their process was all that could be desired. The manager of the Northampton Emery Wheel Co. of Leeds, Mass., says his company finds it to be a very good quality of corundum so far as their wheel is concerned. The president of the American Emery Wheel Works, Providence, R. I., writes: "We have found this material well suited for certain kinds of grinding, especially for saw sharpening, roll grinding, spindle grinding, and surface grinding on hardened steel. For these purposes and perhaps for some others we believe it will come into extensive use, provided it can be furnished at a reasonable price and that the quality runs uniform. Our experiments indicate that on the above classes of grinding it heats the work less than emery."

A number of wheels, together with bricks, rounds and triangles, made from Ontario corundum by different manufacturers according to different processes, have been shipped to Paris, where they are to exhibited in 1900, along with numerous samples of corundum in the raw and partially manufactured state.

J

[UST one hundred years ago, in a paper read before the Royal Society of London and published in its Transactions, Rt. Hon Charles Greville established and named the mineral species Corundum, the crystalline oxide of aluminium; and we have it on the authority of Professor Judd that in an appendix to Greville's paper the Count de Bournon correctly defined the crystallographic characters of the species. The names of its gem-varieties, sapphire and ruby, had been in use from a much earlier time 2; and the name corivindum, or corrivendum, had been given to it by Woodward, in a vaguer way, as early as

1714.

Where Corundum is Found.

In the western part of Asia Minor, and in some islands of the Grecian archipelago, the crystalline limestone which is interbedded with the schists and gneisses

Occurrences of the Mineral.

Oriental Ruby in Burma.

In Burma, which became a British Province in 1886, ruby mines have been worked for a very long period. There the country rock is chiefly gneiss, with bands of crystalline limestone of varying thickness and many miles in length. Most of the mining has been carried on in the hill-wash and alluvium carried down from the decomposed summits of hills and mountain ranges; and it has been observed that where the sands and gravels are mixed with a dark brownish earthy clay, which is a product of the decomposed crystalline limestone, they are richer in such gems as ruby and spinel. The explorations of Barrington Brown appear, indeed, to have satisfactorily established that in Burma the only rock in which rubies are found in place is crystalline limestone. "It is of the usual composition and character of ordinary crystalline limestones," says Mr. Brown, "being made up of finely crystalline or granular limestone in layers, together with irregularly shaped bands of very coarsely crystalline limestone of white and bluish colors, which are interfoliated with the gneissic rocks." Where a quarry has been worked near Mogok, the matrix of the ruby is a coarsely crystalline, semi-opaque limestone of about twenty feet in width. rubies are found over a space of six feet in width, extending almost vertically from the bottom of the quarry to the surface of the ground, and along the centre-line, where the rubies are most numerous, are small developments of a grayish diaspore enclosing small crystals of iron pyrites. As to the limestone itself, whether occuring as disseminated crystals through the gneiss or as great interfoliated masses, it is the opinion of Professor Judd that it has been neither organic nor due to direct chemical precipitation in its origin, but has resulted from a metamorphism of the lime-bearing felspars; while during the process of change from basic felspar to scapolite,

carries a blue corundum mixed with magnetite, which is the emery of commerce. The corundum occurs in smaller quantities as a constituent of granite and gueiss in Silesia, Auvergne and elsewhere in Europe; in a compact felspar rock in Piedmont; in dolomite with tourmaline at St. Gothard; in crystalline limestone, along with numerous other minerals, in Orange and Westchester counties, New York, and Sussex county, New Jersey, and at various localities in Connecticut, Massachusetts and Pennsylvania. It is said by Dana to be common at many points along a belt extending from Virginia across western North Carolina and Georgia to Dudleyville, Alabama.

1 A paper read before the Canadian Institute 10 December, 1898.

? In the Burma corundum every shade of color, from white to the highly prized deep crimson or pigeon's blood, is found, and they are named according to colors instead of composition or system of crystallization-the red variety as oriental ruby, the blue as oriental sapphire, the yellow as oriental topaz, the purple as oriental amethyst, and the green as oriental emerald.

The

it is found at Chester, Massachusetts, in a chlorite belt about twenty feet wide, that lies between formations of hornblende-schist and talc, and traverses the mountains for about four miles. There is also a productive emery mine in Westchester county, New York, which ships from 500 to 700 tons of abrasive emery per annum.

Along the Appalachian mountain chain corundum is found in felspar veins and associated with chlorite in peridotite and serpentine rocks, in amphibolite, dunite and gneiss, as well as in gravel-beds. The principal deposits are found in association with magnesian rocks, chiefly peridotites, which occur as small lenticular masses in gneiss. As a rule however the corundum is neither in the peridotite nor in the gneiss, but in a narrow zone of chloritic minerals between the two. The largest known areas are in the southwestern counties of North Carolina, where corundum was first discovered in 1870. This state has furnished nearly all the corundum of commerce for the United States, but the statistics of the mines and works have never been published. There has been much waste of effort in mining for the gem varieties, encouraged by occasional discoveries, but chiefly by the attractive colors in which the corundum is found. The whole process of

mining and milling has had to be learned by experience; and the task has been made difticult not only by the character of the formations, which is not favorable to sinking or drifting, but also by the closeness with which the corundum crystals adhere to the matrix. For abrasive use it is very important that the corundum should be free from particles of rock or mineral softer than itself; and for use as an ore of aluminium it should be free from all impurities, to make extraction practicable by present methods.

By Dr. in Burgess.

Discoveries in Ontario.

He

The first discovery of corundum in Ontario was made by the late Sterry Hunt fifty-one years ago, in the second year of his Sterry Hunt connection with the Geological Survey of Canada. Dr. Hunt explored part of the county of Lanark in 1847. was joined in some of his excursions by Dr. Wilson of Perth, who at that time enjoyed local reputation as a geologist (the mineral wilsonite is named after him), and who is still remembered as a man who paid considerable attention to the natural history of his district. The first place visited by them was the fourth lot on the eighth range of the township of Burgess, upon which Dr. Wilson a short time before had discovered a body of apatite. Near by, on the second lot of the ninth range, was a deposit of copper pyrites in crystalline limestone, and this was also visited. The only exploration work consisted of two or three blasts, and among the masses of rock thrown out were some composed of silvery mica, with quartz, felspar or albite, and calespar, holding a delicate emeraldgreen and almost transparent pyroxene of rare beauty, as well as crystals of a dark honey-yellow sphene. The mica was often aggregated in masses of small crystals, having

3 Mr. Alexander Rickard of New York, who is owner of a corundum property at Energy, in York county, South Carolina, says in a letter to me of recent date: "All our corundums are very difficult to clean. While the gangue is soft, it is tough, and adheres to the grains of corundum when it is broken up. This reduces the cutting value, and also creates trouble by fluxing when making into wheels."

4

a columnar arrangement, imbedded in which, and disseminated throughout the rock, were a great number of crystalline grains of a transparent mineral, varying in color from a light rose-red to a deep sapphire blue. Dr. Hunt, in his report to Sir William Logan, said:

"Their hardness, which is so great as to enable them to scratch readily the face of a crystal of topaz, showed them to be nothing else than the very rare mineral corundum, which from its colors is referable to the varieties known as oriental ruby and sapphire. The grains obtained were small, none indeed larger than a pepper-corn; but at the time I was on the spot they were not noticed, and the specimens were collected for the pyroxene, in only two or three of which I have since detected the corundum. It is probable that further examinations may develop larger and more available specimens of these rare and costly gems. It is in this crystalline limestone that they generally occur, and the corundum found in the State of New Jersey is in the same rock and with similar mica."5

Yet it does not appear that this discovery in Burgess received further attention from Hunt or other members of the Geological Survey, and the mineral was practically rediscovered there a year ago by Professor Miller of the Kingston School of Mining. It will be seen from Hunt's account that the specimens were collected only for their pyroxene, and that the crystals of corundum were not noticed or identified until a later time.

4 It is not improbable that these were decomposed or altered crystals of corundum. On the metamorphosis of the mineral Professor Judd says: "At the earth's surface, as is well-known, corundum or the crystallized oxide of aluminium is one of the most unalterable substances. Fragments found in river gravels and sands, though perfectly water-worn, show no trace of chemica! alteration in their surfaces. On the other hand, there can be no doubt that conditions must exist in the earth's crust under which chemical change of this mineral does take place; this is abundantly proved by the frequency with which undoubted pseudomorphs of corundum occur. Among the minerals found replacing corundum as pseudomorphs are muscovite (damourite), various forms of spinel, andalusite, fibrolite, cyanite, margarite, chloritoid, zoisite, ripidolite and other chlorites, various vermiculites, kaolin, and other substances." Geol. Sur. Can. 1847-8, p. 134.

By Henry Robillard in Raglan.

The largest known deposit of corundum in the Province was discovered twenty-two years ago on the farm of Henry Robillard, in the township of Raglan, Renfrew county; but in this case twenty years elapsed before the mineral was correctly identified. According to Robillard's story, he was returning with his little daughter from a cranberry marsh on the wide flats of York river, and, in climbing a hill which rises about 500 feet above the river, he sat down upon a large boulder to rest. In telling me the story Robillard said: Annie was kneeling behind me, and picked up a queer-shaped stone, and, showing it to me, said it looked like the stopper of a cruet-bottle. It was just like that; and I wondered what fool of a man had gone to work and whittled it out. Then I looked at the stone where I was sitting; and. bless you, sir, it was paved with cruet-stoppers. And here is the very boulder now," he added, as we reached the spot, about half-way down the hill.

Specimens gathered by Mr. Robillard were shown to several persons in Combermere, and one who professed to be a miner of phosphate of lime in Lanark county pronounced them to be crystals of that mineral. In 1884 one John Fitzgerald joined with Robillard in an application to the Crown for the mineral rights on the property, including several lots on the 18th and 19th concessions of Raglan ; and for a number of years they sought in vain for a customer to buy an apatite mine. The sturdy pioneers would brook no contradiction of their claim that the mineral was veritable apatite; and when a doubt was raised by two young mineralogists who visited the region about ten years ago in the interest of a capitalist, and a suggestion was meekly made that it might be emery, one of the pioneers cut negotiations short by threatening to "punch their heads." Last year, however, these pioneers were overjoyed to learn on the authority of an expert that the mineral was not apatite, but corundum.

Twelve years ago, in 1886, Nesbitt T. Armstrong, a farmer and mill-owner in Carlow, discovered corundum on lot 14, in the 14th concession of that township, but he did