region the methods employed are as rapid and at the same time as reliable as may be found in use, in any district, in the commercial analysis of iron ores.

That the present compilation is in many respects crude and imperfect we are well aware. We desired and attempted to reach all the chemists of the region and wished to give all an opportunity to contribute to the work. Doubtless some may have been missed which we regret, and there may be others who have worked up some methods that at present they do not care to give out. However because of the general responses to our letter and of the geographical distribution of the same we feel that the present attempt at compilation fairly well represents the present status of analytical chemistry of iron ores of the district. The reports coming from the chemists of the different mining sections are distributed as follows: From Minnesota five, representing the Vermilion and Mesabi ranges, from the Gogebic range six, from the Menominee range six, from the Crystal Falls district two, from the Marquette range four, from the Baraboo district, Wisconsin, two and from Ontario one. Total twenty-six. An examination of the reports shows the following general data.

Two methods are in general use in the determination of iron: One, the permanganate method, is used by seventeen chemists, the other, the bichromate method by nine.

In the determination of phosphorus three general methods are described with varying modifications in manipulation. One the handy Alkalimetric method in which the phosphorus is precipitated as yellow ammonium phospho-molybdate, dissolved in standard sodium hydrate, and titrated with standard nitric acid, is used by thirteen of the chemists; the Emmerton method in which the yellow precipitate is dissolved in ammonium hydrate, reduced with zinc and sulphuric acid, and titrated with potassium permanganate, is used by seven; and a modification of the Wood method, described in Blair's "Chemical Analysis of Iron," in which the phosphorus is determined gravimetrically by weighing the yellow ammonium phospho-molybdate precip

itate, is used by five of the chemists. In a few cases two of the three methods are reported.

Three methods of more than the usual rapidity are described, one by F. A. Janson, of Vulcan, another by John McNamara, of Ironwood, and a third by W. A. Siebenthal, of Republic, Mich., all being modifications of the handy method.

In the determination of silica two methods are described. The sodium carbonate fusion method is used by eleven; the hydrofluoric acid method by six; both being used by some of the chemists.

Volhard's method for manganese, with varying modifications, is used by fourteen of the chemists; Julien's method by two; and a gravimetric process is described by one.

Of those reporting methods for the determination of calcium, nine use a gravimetric method, precipitating the calcium as calcium oxalate; igniting and weighing as calcium oxide. One uses a gravimetric process, titrating with potassium permanganate.

Magnesia is determined gravimetrically as magnesium pyrophosphate by nine and alumina as aluminum phosphate by a like number of the chemists who report methods for such determinations.

Sulphur is determined as barium sulphate by those reporting on the determination.

One chemist describes a method for the determination of titanium.

Methods for moisture determination are described by four chemists, and a like number report methods for organic and volatile matter.

The interest and value of this collation of methods, to the chemists of the region, it seems to me, lies in and is to be obtained from the differences in detail and manipulation as well as in the general differences of methods. Already have I found myself making some changes in my own work, applying some of the details given by some of the chemists in their descrip

tions. In conclusion while the methods described may be as rapid and reliable as any in general use, it seems to me that there is a possibility for improvement and an excellent opportunity for research along the line of both shortening and simplifying some of the methods given, especially in the determination of phosphorus.

A method for the direct oxidation and dissolving of the phosphorus without the complete solution of the ore would considerably shorten the process. The two methods given for the determination of iron are quite simple when compared to those described for other substances, yet each has certain objections; the permanganate method because of the inconstancy of strength of the solution; the bichromate method is slower and requires the use of an external indicator. An internal indicator would be a decided improvement in the latter method.

We are indebted to Mr. D. T. Morgan and Mr. Wm. Kelly for courtesies and aid extended in the compilation of the work and also desire to thank the other superintendents and general managers who have co-operated in the work in furnishing us with the names and addresses of their chemists or who referred our letter of inquiry to the chemists in charge of the laboratory work.

I. METHODS USED AT THE LABORATORY OF THE OLIVER IRON MINING COMPANY, VERMILION RANGE, ELY, MINN.

BY CLARENCE J. MOTT.

DETERMINATION OF IRON.

Weigh .5 gram of ore into a No. o Griffin beaker. Add 5 cc. stannous chloride, 10 cc. hydrochloric acid and heat until in solution. Remove from hot plate and complete the reduction with stannous chloride solution, adding 1 or 2 drops in excess, and allow to cool. Pour into a No. 4 beaker and dilute to 300 cc. with water. Add 2 or 3 cc. of saturated solution of mercuric chloride, to precipitate any excess of tin, and 20 cc. of

titrating solution. Stir; place under a burette and titrate with a standardized solution of potassium permanganate.

SOLUTIONS.

Potassium Permanganate Solution.—4.417 grams potassium permanganate to I liter of water.

Stannous Chloride.-100 grams of stannous chloride dissolved in 500 cc. hydrochloric acid and made up to 1 liter with

water.

TITRATING SOLUTION.

A. 16 grams of manganese sulphate, and 16 cc. of water. 33 cc. of phosphoric acid and 47 cc. water.

B.

C. 32 cc. sulphuric acid and 48 cc. water.

Make up separately and when in solution and cool, mix all together and shake.

DETERMINATION OF TOTAL PHOSPHORUS.

Weigh three grams of ore into a No. 2 beaker; add 25 cc. hydrochloric acid and dissolve on the hot plate. When in solution oxidize with a few drops of nitric acid, and evaporate to 10 cc. Remove from plate and filter into a 16 oz. flask. Fuse the insoluble residue with sodium carbonate. Dissolve the fusion with water; acidulate with hydrochloric acid; evaporate to dryness, and dehydrate. Redissolve in water, using a few drops of hydrochloric acid, and filter into the original filtrate. Precipitate the iron with ammonium hydrate, adding a few drops in excess; neutralize with nitric acid; heat to 60°C. and precipitate the phosphorus with 25 cc. of molybdate solution. Shake well and allow to settle for one hour. Filter and wash. free of iron with solution of ammonium sulphate, washing three times by decantation and five times on filter. Place the funnels containing the yellow precipitate over the flasks, in which the phosphorus was precipitated, and dissolve the precipitate in 20 cc. ammonium hydrate (1:3) solution. Reduce with 10 grams of granulated zinc and 75 cc. sulphuric acid (1:4) solution. Bring to boil on the hot plate; filter, wash with water and titrate with the same potassium permanganate soluion as used for the determination of iron.

SOLUTIONS.

Molybdate Solution.-Dissolve 100 grams of molybdic acid in 400 cc. ammonium hydrate (sp. gr. .96) and add to

1500 cc. nitric acid (sp. gr. 1.20), shaking well after each addition.

Ammonium Sulphate Solution.-271⁄2 cc. ammonium hydrate and 24 cc. sulphuric acid. Make up to a liter with

water.

DETERMINATION OF INSOLUBLE PHOSPHORUS.

Weigh 5 grams of ore into a No. 3 beaker; add 30 cc. hydrochloric acid; dissolve on hot plate. When in solution, oxidize with nitric acid; evaporate to dryness and dehydrate. Redissolve and filter. Fuse the insoluble residue with sodium. carbonate. Dissolve the fusion in water and acidulate. Evaporate to dryness and dehydrate. Cool; redissolve in water, using a few drops of hydrochloric acid, and filter to aid in neutralizing and proceed as for total phosphorus.

DETERMINATION OF SILICA.

Weigh I gram of ore into a No. 1 beaker; add hydrochloric acid and dissolve on hot plate. Evaporate to dryness and dehydrate. Cool; redissolve with a few drops of hydrochloric acid and filter, carefully rubbing the beaker. Fuse the insoluble residue with sodium carbonate. Dissolve the fusion. with water; acidulate; evaporate to dryness and dehydrate. Redissolve the fusion in water, using a few drops of hydrochloric acid. Filter, and wash 12 times with hot water, rubbing the inside of the beaker well with a policeman. Ignite and weigh as SiO2.

DETERMINATION OF MANGANESE.

Volhard's method as given on page 118, third edition of Blair's "Chemical Analysis of Iron," modified to suit these ores, is used.

DETERMINATION OF ALUMINA.

Peter's modification of Wohler's method as given on page 251, third edition of Blair's Chemical Analysis of Iron is followed in detail.

DETERMINATION OF CALCIUM AND MAGNESIA.

The method described in "Methods for the Analysis of Limestone", page 267, third edition of Blair, is used.

DETERMINATION OF SULPHUR.

The method used is that given on page 51, N. W. Lord's Notes on Metallurgical Analysis.