Members who require extra sets or back numbers of the Journal are requested to make application to the General Secretary only, to whom also changes of address should be communicated.

Authors of communications read before the Society, or any of its Local Sections, are requested to take notice that under Rule 41 of the bye-laws, the Society has the right of priority of publication for three months of all such papers. Infringement of this bye-law renders papers liable to be rejected by the Publication Committee, or ordered to b abstracted for the Journal, in which case no reprints can be furnished to the author.

Notice is hereby given, for the information of members and advertisers, that the advertisement columns of this Journal have been contracted for by Messrs. EYRE and SPOTTISWOODE, the Society's printers and publishers, to whom all communications respecting them should be addressed.

The Secretary is prepared to offer 5s. apiece for copies of the Society's Journal for January 1883 in saleable condition.

LIST OF MEMBERS ELECTED, 23rd FEBRUARY 1893.

Bateman, John, Chester Street, Saltney, Chester, manager of candle and sulphuric acid works.

Boyce, Frank, c/o Goodall, Backhouse, and Co., White Horse Street, Leeds, chemist.

Briggs, J. F., c/o Parry and Co., Madras, India, sugar works chemist.

Brothers, H. E., Victoria Institute, Tunstall, Stoke-onTrent, analyst.

Cannon, J. C., 70, Ham Park Road, Forest Gate, Essex, analyst.

Cowan, W. J., 77 Trinity Road, Wood Groen, N., fine colour manufacturer.

Crowther, Edw., Woodland Dyeworks, Headingley, Leeds, dyer.

Delahaye, Philibert, 65, Rue de Provence, Paris, gas engineer.

Dann, W. II., jun., 1, Belle Vue Terrace, Gateshead-onTyne, analytical chemist.

Edwards, Vincent, 44, Victoria Avenue, Upton Park, Essex, manure company's chemist.

Gardiner, H. J., c/o J. Pattison and Co., 11, Bothwell Street, Glasgow, traveller.

Gendall, W. H. S., Gas Works, Elton, Bury, gas engineer.

Gibbs, Wm. T., Buckingham, Province of Quebec, Canada, analytical and manufacturing chemist.

Green, F. C., Chihuahua, Mexico, mining superintendent and manufacturer.

Guthrie, John A., 34, Lancaster Park, Richmond, Surrey, chemical merchant.

Hendrichs, Frank H., Imperial Wharf, 46, Bankside, S.E., chemical merchant.

Isaac, Jno. F. V., 18, Montserrat Road, Putney, S.W., research chemist.

Jackson, Jas.. Dominion Cotton Mills Company, Magog, Province of Quebec, Canada.

Johnson, Ben H., Caroline Cottage, West Grove Road, Woodford, Essex, contractor.

Jones, David S., Wilson Terrace, Coatbridge, N.B., analytical chemist.

Lawton, Thos., Calthorpe House, Aldridge Road, Perry Bar, Birmingham, chemical works manager.

Lloyd, Herbert, Gloucester, N.J., U.S.A., chemist and electrician.

Loughton, J. P., Washington Chemical Works, co. Durham, chemist.

Mather, Colin, Salford Iron Works, Manchester, engineer. Oswell, Benj. L., 71, Spring Terrace Road, Burton-onTrent, brewer's analyst.

Perkins, T. S., 39, Garden Place, Brooklyn, N.Y., U.S.A., technical chemist.

Pilley, Thos. W., Crescent Lodge, Camberwell Grove, S. E., analytical chemist.

Reckie, J. A., 5, Simmondley Lane, Glossop, Derbyshire, assistant colour mixer.

Ritchie, Geo., c/o Beardmore and Co, Parkhead Forge, Glasgow, analytical chemist.

Saltmarsh, J. G., 147, Shrewsbury Street, Brooks Bar, Manchester, works chemist.

Schlesinger, Dr. Jas., P.O. Box 368, Pretoria, S.A. R., analytical chemist.

Scott, Herbert, 48, Ashmore Road, Harrow Road, W., metallurgist.

Smith, Edgar B., c/o Burt, Boulton, and Haywood, Selzaete, Belgium, chemist.

Stewart, Alexander F., Box 1283, Johannesburg, S.A.R., chemist and assayer.

Sträuli, Emil, Winterthur, Switzerland, soap and candle manufacturer.

Travers, Morris W., 2, Phillimore Gardens, Kensington, W., chemical student.

Wilcox, H., Stanford-le-Hope, Essex, manager of explosives factory.

CHANGES OF ADDRESS

Anderson, E. E. J., Journals to 4 Muirpark Gardens, Partick, Glasgow.

Baker, Theodore, 1/o New Jersey; Longfield, near Dartford, Kent.

Bell, P. Carter, 1/o Fleetwood; c/o Mersey Rubber Co., Bank Quay, Warrington.

Berry, E. C., Journals to Casa Balestra, Bordighera, Italy. Bowrey, J. J.; (subscription only), 62, Penshurst Road, South Hackney, N.E.

Butterfield, W. J. A., 1/o St. John's; Beckton, E. Canziani, E., Journals to 3, Palace Green, Kensington, W. Carter, W. Chas., 1/o Eblana Street; 5, Abercorn Street, Lisburn Road, Belfast,

Church, E. D., 1/o Milton Street; c/o Church and Co., 36, Ash Street, Brooklyn, N.Y., U.S.A.

Cooper, H. P., Journals to 2, New North Road, Hoxton, E. Dagger, J. II. J., lo Stoke-on-Trent; 5, Lorne Street, Fairfield, Liverpool.

Dixon, M. T., 1/o Box 419; P.0). Box 1816, Johannesburg, S.A.R., South Africa.

Duckworth, Wm., Journals to Shawe Hall, Flixton, near Manchester.

Dunwoody, R. G., 1/o Calhoun Street; 369, Piedmont Avenue, Atlanta, Ga., U.S.A.

Field, S. E., 1/o Halifax; Lewin's Mead Brewery, Bristol. Flanagan, C. A., l/o Manchester; Hegewisch, Ill., U.S.A. Fletcher, A. E., 13 (not 15) Christchurch Road, Crouch End, N.

Freeman, A., l/o St. Helens; 111, Needham Road, Edge Hill, Liverpool.

Hamaguchi, K., Journals to e/o Mitsui and Co., 1, Crosby Square, E.C.

Hammill, M. J., 1/o Cooper Street; 9, Windle Street, St. Helens.

Harvey, E. Feild, l/o London; Omrac, St. John's, Newfoundland.

Hinman, B. C., l'o Flushing Avenue; c/o Ironclad Manufacturing Co., 186, Cook Street, Brooklyn, N.Y., U.S.A.

Isaac, F. W. Player, 1/o Bath; 114, Marine Parade, Brighton.

Peacock, S., l/o Philadelphia; Finley's Post Office, N.J., U.S.A.

Pilkington, G., 1/o Manchester; Old Market Place, Bury. Reibstein, Dr. T., l/o Brussels; Engelbostelerdamm 61, B, I, Hannover.

Rideal, Dr. S., o St. Moritz; Chemical Laboratory, St. George's Hospital, S.W.

Rigby, J. S.; Journals to Hotel Vancouver, Vancouver, British Columbia.

Rothwell, C. F. Seymour, l/o Dinting; 82, Mawson Street, Ardwick Green, Manchester.

Scott, Fred., 1/o Middleton; Fred. Scott and Co., Littleboro', near Manchester.

Shimidzu, T., o Chicago; 2,111, North Jeff Street, Peoria, Ill., U.S.A.

Simonds, Dr. F. M., o New York; 128, Sandford Avenue, Flushing, Long Island, N.Y., U.S.A.

Sowerby, W. M., 1/o United Alkali Company; Stanley Villas, Higher Runcorn.

Stern, A. L.; Journals to 170, Ashby Road, Burton-onTrent.

Stillwell, C. M.; Journals to c/o Stillwell and Gladding, Box 1,261, New York, U.S.A.

Sumner, Harold; Journals to Butt Hill, Prestwich, Manchester.

White, H., o 80; Berlin Terrace, London Road, Carlisle.

Meeting held Monday, 6th February 1893.

MR. WM. THORP IN THE CHAIR.

ON THE DETECTION AND ESTIMATION OF LEAD IN TARTARIC AND CITRIC ACID.

BY R. WARINGTON, F.R.S.

THE manufacture of tartaric and citric acid has usually been largely conducted in leaden vessels; lead has particularly been used for the evaporating baths in which the liquors are concentrated to the crystallising point, and for the vessels in which crystallisation takes place. The sulphuric acid used to decompose the tartrate and citrate of calcium has also served to introduce lead. Small quantities of lead have thus been generally present in commercial citric and tartaric acid, and in recent pharmacopoeias the presence of lead is mentioned as a possible impurity, and methods given for its detection.

I am rot aware that any cases of lead-poisoning have been traced to the use of tartaric or citric acid, but as these acids are largely used in the preparation of lemonade, ginger beer, and effervescing medicines, and tartaric acid is a large ingredient of ail baking-powders, it is clearly desirable that lead should either be absent, or exist in a proportion so small as to be insignificant.

Public attention has been called to this matter frequently during the last few years. A threatened prosecution for the sale of lemonade containing traces of lead has led some makers to abandon the use of citric or tartaric acid altogether and to employ phosphoric acid instead.

In July last a prosecution was instituted by the Woolwich Local Board of Health against an oil and colour-man in their district for selling tartaric acid containing 0.0026 per cent. of lead, which their analyst, Dr. W. R. Smith, stated to be a poisonous quantity.* This prosecution failed, the magistrate holding that the small amount of lead present became unavoidably mixed with the acid during the process of manufacture. Dr. W. R. Smith has since published in the Journal of State Medicine, October 1892, 57, determinations of lead made by him in numerous samples of tartaric and citric acid.

Public attention has also been called to the subject in France during the past year, owing to the refusal of a delivery of tartaric acid by the Government on the ground of its contamination with lead. M. Ch. Buchet, director of the Pharmacie centrale, has in consequence made an examination of the tartaric and citric acids of commerce, and has published his results in L'Union pharmaceutique, May 1892, 203.

It is now about two years since the firm of J. B. Lawes and Co., of Millwall, London, determined to introduce improvements into their manufacture of tartaric and citric acid, with the view of preparing these acids free from lead. Having many years ago been chemist to this firm, I was asked by Sir J. B. Lawes to assist in the work, and especially to find, if possible, a satisfactory method for determining the amount of lead present in tartaric and citric acid, as much uncertainty appeared to exist on this point. The present paper is to be regarded as a report on this special branch of the investigation.

As to the process now employed at Millwall for obtaining acid free from lead, I need only say that the manufacture is conducted in the usual way in leaden vessels up to the first crystallisation, and that the acid is then redissolved, purified from lead with hydrogen sulphide, and the liquor subsequently evaporated and crystallised in lead-free vessels: this mode of proceeding was adopted as requiring the least disturbance to the factory plant. After many trials to ascertain the best mode of working, the process has proved quite successful.

For the purposes of this paper we have to consider: 1. The detection of lead; 2. The quantitative determination

* That so small a proportion of lead could be injurious was not substantiated by the evidence of other experts at the hearing.