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Royalty was paid at the Department of Lands and source of wealth to the colony for many years to Mines on 101,325 ounces for the year ending June,

Mr. Linck, an experienced mining engineer, 1903, while for the same period ending 30th June, says that the alluvial auriferous deposits have so 1904, royalty was paid on 87,442 ounces.

The

far scarcely been touched. Up to the present, only reasons for this falling off are not far to seek. Many the beds of the streams carrying only a little water, of the smaller placers, which had been formerly have been worked by the “pork-knockers" with the worked systematically, have either been abandoned crudest of appliances, and in other cases by small or been handed over to the rough and ready methods syndicates whose appliances for handling dirt are of the “ maraudeurs." Local capital has not been little ahead of the pork-knockers. There is no doubt forthcoming to any extent, and any influction of out- that in the known gold-fields, the more easily worked side capital has been directed either to quartz- creeks have been practically exhausted, thus accounting mining, diamond mining, to the revivication of for the falling off in the gold out-put of the colony. mining proper, or to hydraulicking. With regard to Attention must now be directed to working the the latter, it must be remembered that topographical auriferous deposits on the slopes of the hills, which, difficulties have had to be overcome by the importa- there is no doubt, occur in large areas and only want tion of machinery on a large scale, and that therefore capital to develop. In many parts of the gold-fields the expected results have not gone to swell the water can be conveyed on to these alluvial deposits returns of the past year.

by means of ditches, while in others it would be When we come to examine in detail the production necessary to pump the water to work the ground as of the various districts, we find that the Barima district is done by the Omai Gold Mining Company, which shows a falling off of nearly 3,000 ounces, the Barama is working very profitably deposits of gold-bearing of nearly the same amount, and the Cuyuni 3,910 wash, that it would be impossible to get water on to

The Puruni shows a small decrease of 435 otherwise than by pumping machinery. But it is ounces; probably this would have been greater had doubtful as to whether many of the claims which are it not been for the working of the Peters' Syndicate, now being systematically worked could not be made to which have not been alluvial in the proper sense of the pay should some impetus be given to the outlay of local word, the gold being derived from quartz crushed capital in the direction of affording the small capitaby hand-power. The Mazaruni shows a decrease of list some assurance that his interests would be safeover 1,000 ounces, while the Essequebo alone enjoys guarded, and that his gold would not be stolen, his the distinction of showing an increase of 571 ounces, provisions wasted and the labourers induced to desert due to the workings at Omai, a striking exemplifi- their employer, lured away by, to them, the superior cation of the superiority of systematic working. The attractions of “maraudage." Potaro shows a decrease of 3,358 ounces, which is Diamonds.—The export of diamonds for the past only to be compared with that of the Cuyuni, a river year shows a slight increase over that of 1902-3. which shares with it the reputation of being worked During the year ended 30th June, 1903, 10,559 to a great extent by undirected and unsystematic carats weight, valued at 96, 190 dols., were exported, methods.

and during the same period of 1903-4, 11,200 carats, It is not to be concluded by any means that this valued at 92,431 dols., were exported. The number falling off is any indication as to the possibilities of of stones declared at the Department of Lands and the colony, even alluvially, as it is the consensus of Mines for the past year was 167,296, weighing opinion amongst experienced and trained mining 11,303 carats, but it is extremely probable that the engineers who have made thorough investigations shipments for July will be much greater than for any during the past year that the resources of the country previous month in the year. There have been some from the point of view of gold are practically un- suggestions made as to the amalgamation of some of touched, and that the Auctuations in the production the companies with a view to lessening the cost of of small workings in the creek beds and flats cannot transportation and management. The former quesbe taken as any indication of the enormous amount tion, that of transportation, is still a great drawback of alluvial existing in the spurs and slopes of the hills to the industry, and if some means can be devised of which ought to give a good return for scientific and lessening the cost of taking up provisions over the up-to-date working for many years to come. It has falls of the Mazaruni an undoubtedly great impetus been stated by a geologist of repute, Dr. Lungwitz, would be given to this growing and important that in one district prospected by him there exists a industry. The number of labourers registered for the layer of auriferous gravel extending for some twenty- Mazaruni diamond fields during the year was 1,145. two miles, and having a width of half a mile and a Forest Products:— The amount of balata exported depth of two to three feet. He estimated that every from the colony during the past year shows 547,601 lbs. cubic yard of this gravel carried about 65. 3d. worth as against 490,174 lbs. for the preceding year. Timber of gold to the ton, and with power existing by which showed a slight decrease, 304,881 cubic feet being it could be cheaply worked from the neighbouring exported, as against 319,438 cubic feet for the prefalls. Professor Harrison, the Government geologist, ceding year. Shingles were exported to the value of has also given his opinion that the iron-capped hills 94,112 dols., or an increase of 3,988 dols. over 1902-3; of the Essequobo and Potaro districts should prove a firewood to the value of 11,842 dols, as against 2,275

dols. ; and gums 11,549 lbs. as against 6,558 for The results are interesting, and there are many 1902-3. Charcoal, 80,800 bags, to the value of arguments for and against it. Various devices have 40,575 dols., were exported, as against 74,383 bags, been attempted in order to secure the occupation of valued at 58,621 dols., for 1902-3. It would thus municipal houses by the really poor. appear that the minor forest industries of the colony (6.) Some advocate the plan of building ordinary are capable of considerable expansion, and that a houses or tenements in large number in order that large market exists in the West Indies themselves for municipal competition may lower the level of rents. charcoal, hardwood and shingles. These industries The results of this are slight. appear to be almost altogether confined to the Deme

(c.) Recently attempts have been made to develop rara River, and indeed would seem to be the staple suburban estates. This seems hopeful, but there are industries of that district. It would be interesting to many difficulties, especially as to providing for the know the number of persons employed in these very poor on such estates. various industries, which aggregate apparently an The main task of house building must be left to export of 342,947 dols., in addition to the value of

private enterprise; the duty of local authorities is to the timber, shingles, firewood and charcoal retained

urge private enterprise to do the very best that can be for home consumption. It would scarcely be going done. There are two main ways of bringing this too far to suppose that something like three times the about: (1) By wise building by - laws properly amount exported is consumed in the colony.

enforced; (2) by thorough administratiou of the Questions of labour, prospecting licences, un- sanitary laws. These two duties are at present very registered labourers, &c., are also discussed in this imperfectly performed. The urgent necessity of Report.

guarding suburbs and new districts is not yet realised.

Local authorities have experienced great difficulties, especially financial difficulties, as to their building

schemes, but recent developments seem more hopeful. THE TOWN HOUSING QUESTION.* Local authorities ought (1) to make experiments, The fundamental difficulty of the question is the

lead, and suggest (examples, Sheffield and Camber. growth of town populations which have been housed well); (2) in cases of monopoly create competition ; without any regard to hygienic conditions.

(3) where necessary deal with classes which cannot be There are two main aspects of the problem : (1) the

left to private enterprise, but great caution is essential sanitary aspect, i.e., the existence of slums and in- to the success of such plans. sanitary areas; and (2) the house famine. This, again, is of two kinds: first, and more rarely, a house famine due to special circumstances, e.g., when the sudden growth of an industry causes an abnormal

THE ELECTRICAL CONDUCTIVITY OF

con UCTIVITY increase of population ; second, a constant difficulty

CERTAIN ALUMINIUM ALLOYS AS as to the supply of cheap houses. Increased cost of

AFFECTED BY EXPOSURE TO LONDON building has not checked the growth of superior

ATMOSPHERE.* house accommodation, but has interfered with the production of cheap houses, while improvements This paper deals with the effect upon electrical remove the old inexpensive cottages. Hence there is conductivity of exposing light aluminium alloys to great pressure on those which still exist.

London atmosphere. During three years' exposure How have local authorities attempted to cope with the copper-aluminium alloys hare gradually dimi. these difficulties ?

nished total conductivity to a greater extent the 1. In the case of insanitary areas they have used greater the percentage of copper. The nickel-copper Part I. of the Housing Act; in the case of small aluminium alloys, which show such remarkably ingroups of bad houses improvements have been creased tensile strength as compared with good effected by Part II. and by the Public Health Act. commercial aluminium, have during the last year

2. The preventive and regulative work of the considerably diminished total conductivity. On the sanitary authorities has done much, and might do other hand, the manganese-copper aluminium alloys more, to improve bad conditions and to stimulate have suffered comparatively little diminution in total healthy effort.

conductivity, and one of them has comparatively high 3. Lastly, there have been attempts to deal with tensile strength. It was thought that an examinathe house famine by means of municipal house tion of the structure of these alloys by aid of microbuilding and owning. There are several different photography might throw some light on the great policies with regard to this.

difference which exists between some of their physical (a.) The Liverpool policy of cheap tenement houses properties. For instance, a nickel-copper aluminium on central sites, the object of which is to rehouse the alloy has 1.6 time the tensile strength of ordinary very poorest classes who now occupy court houses. commercial aluminium. Under a magnification of

Abstract of paper read by Mrs. Fisher before Section F. of the British Association at Cambridge.

* Abstract of paper by Professor Ernest Wilson, read before Section G of the British Association at Cambridge,

800 diameters practically' no structure could be discovered. Considering the remarkable crystalline structure exhibited by ordinary commercial aluminium near the surface of an ingot, when allowed to solidify at an ordinary rate, the want of structure in these alloys must be attributed to the process of drawing down. The inference is that the great difference which exists between their tensile strengths and other qualities is not due to variation in structure. The experiments in micro-photography have been carried out by aid of a portion of the Government grant voted to me by the Council of the Royal Society.

Notes on Books.

jIX LECTURES ON PAINTING, delivered to the

Students of the Royal Academy of Arts, January, 1904. By George Clausen, A.R.A., Professor of Painting. London : Elliot Stock.

The author, in considering the present position of the Fine Arts and the adverse circumstances of the times, refers to an anecdote of the condition of painting in the early days of the art which is related by Lanzi. Orcagna, in the first quarter of the fourteenth century, asked the question of his companions, “Who was the greatest master, setting Giotto out of the question ? " Some answered Cimabue, some Stephano, some Bernardo, and some Buffalmacco. Taddeo Gaddi said, “Truly these were very able painters, but the art is decaying every day.” Mr. Clausen considers this to be comforting and that it shows how the relation of the artist to the world in general was always much the same as it is now. After an introduction on some early painters the subjects of the several chapters are “. Lighting and Arrangement," Colour," " Titian, Velasquez, and Rembrandt," " Landscape and Open-air Painting.” concluding with “Realism and Impressionism.”

student and beginner, while at the same time includ. ing all recent developments likely to be found of value in practical work.

The chemistry of the various processes has therefore been set out in some detail, and methods which have been recently proposed are fully explained. A good deal of space is given to a description of the properties of the more important oils, fats and waxes, with the method for their investigation.

There are also chapters on the physical and chemical properties of oils and fats, as well as on the methods for estimating their constituents. A RECORD OF THE INTERNATIONAL FIRE Ex

HIBITION, EARL'S-COURT, LONDON, 1903. By Edwin 0. Sachs, Chairman, British Fire Protec. tion Committee. London.

This volume contains a fully illustrated account of the proceedings at this important Exhibition, which was held last year, and a description of the exhibits. Special attention is given to the remarkable Loan Exhibition, in which were shown interesting historical objects relating to Fire Prevention, Fire Protection, Fire Insurance, and Fire Literature, also Portraits and Models, Monuments and Mementoes of Fire Heroes and Worthies, Pictures of Fires, Commemorative Medals, &c. The Collection of English Antiquities was fully supplemented by special foreign exhibits from France, Germany, Holland, Italy, and Russia. The editor claims that the particulars of the collection will serve as an outline of the history of fire extinguishing during the last three centuries, more particularly if studied in connection with the notes of Chief Officer Graham, of Hampton, who was responsible for the correct execution of the Historical Pageant in the Exhibition Theatre. IMPERIAL INSTITUTE OF THE UNITED KINGDOM,

the COLONIES, AND INDIA. Technical Reports and Scientific Papers. Edited by Wyndham R. Dunstan, M.A., F.R.S. London.

The Reports refer to Coal, Iron Ores, and various Minerals, Fibres, Oils and Oil-Seeds, Rubber and Gutta-Percha, Gums and Resins, Medicinal Plants and Tobacco, Tanning and Dyeing Materials, Fodder Plants and Food Grains, Timber, &c. The scientific papers are devoted to important chemical investigations respecting the technical value of materials sent to the laboratories of the Institute.

A TEXT-BOOK ON CERAMIC CALCULATIONS, WITH

EXAMPLES. By W. Jackson. London: Longman's, Green, and Co.

The author has not attempted to write a text-book on pottery manufacture but to give help to classes in pottery and porcelain by printing a collection of examples showing the application of mathematical and chemical methods to the consideration of the problems presented for solution in the course of the manufacture.

THE ANALYSIS OF OILS AND ALLIED SUB

STANCES. By A. C. Wright, M.A., B.Sc. London : Crosby Lockwood and Son.

The author's intention has been to present an account of the methods used in the analysis of oils, fats, and waxes in a form suited to the needs of the

THE ELECTRO-PLATING AND ELECTRO-REFINING

OF METALS. By Alexander Watt and Amold Philip, Assoc. R.S.M., B.Sc. London: Crosby Lockwood and Son.

This is a new edition of Alexander Watt's wellknown work on “ Electro Deposition.” The present edition is divided into two parts: Part I. on ElectroPlating, and Part II. on Electro-Metallurgy. Mr. Philip has contributed some two hundred and twenty pages of fresh matter, including chapters on the cost of electrolytic copper refining, and on some important details in electrolytic copper refineries.

Journal of the Society of Arts.

Proceedings of the Society.

No. 2,705.

VOL. LII.

CANTOR LECTURE.
OILS AND FATS—THEIR USES AND

APPLICATIONS.
FRIDAY, SEPTEMBER 23, 1904. BY DR. J. LEWKOWITSCH, M.A., F.I.C.

Lecture 11.-Telivered February ist, 1904. All communications for the Society should be addressed to

We have seen in the last lecture how the raw the Secretary, John-street, Adelphi, London, W.C. oils and fats are prepared by modern methods.

The oils and fats thus obtained are in their

fresh state practically neutral. If care be Notices.

exercised in the process of rendering animal oils and fats, the fatty matter is very often sufficiently pure to be immediately worked up

in those industries to which they serve as raw OWEN JONESPRIZE.

materials. If, however, they are allowed to This competition was instituted, in 1878, by remain in contact with animal tissue, they the Council of the Society of Arts, as trustees are liable to very rapid deterioration. Thus, of the sum of £400, presented to them by the freshly rendered lard or suet, or even whale Committee of the Owen Jones Memorial, being oil, will keep sweet for a very long time if the balance of subscriptions to that fund, protected from light, air, and moisture, whereupon condition of their expending the interest as the same materials through prolonged conthereof in prizes to “ Students of the Schools tact with putrescible animal matter become of Art who, in annual competition, produce dark in colour, and rich in free fatty acids. the best designs for Household Furniture, This is especially exemplified by the five Carpets, Wall-papers and Hangings, Damask, samples of whale oil shown here. Of these, Chintzes, &c., regulated by the principles whale oil “No. 0,” is perfectly sweet and laid down by Owen Jones.” The prizes are water white, whereas the lower grades passing awarded on the results of the annual com- through whale oil“ No. 1” to “No.4," become petition of the Board of Education, South gradually darker, and finally acquire an offenKensington.

sive odour, in consequence of having remained Six prizes were offered for competition in the in contact with the flesh and bones for a somepresent year, each prize consisting of a bound what prolonged time. copy of Owen Jones's “Principles of Design, The vegetable oils obtained by expression and a Bronze Medal.

contain frequently mucilaginous matter and The following is a list of the successful other impurities, such as vegetable fibres, candidates :

which pass through the press cloths. There

are also admixed with the oils traces of moisRudge, Margaret M., Battersea Polytechnic School of Art, London, S.W. Design for Printed

ture, which render them somewhat turbid, Muslins.

dark, and unfit for immediate use; not only for Lavington, Clara, School of Art, Leeds.-Design

the table, but also for manufacturing purposes. for Embroidered Screen.

Formerly these impurities were removed from Harford, Ida, Battersea Polytechnic School of Art,

edible oils, such as olive oil, by the simple London, S.W.-Design for Printed Muslin.

method of allowing the oils to rest for some Metcalf, Arthur, School of Art, Carlisle.- Design

length of time, when the moisture and the for Tiles.

mucilaginous matter, &c., would settle out.

This crude process is no longer employed in Pickford, Percy, School of Art, Macclesfield.--De

large establishments, the clarifying of the oils sign for Tile Panel.

being much shortened by filtering through a Oldfield, Arthur, School of Art, Macclesfield.--De

filter press, or brightening by blowing with air. sign for Silk Hanging.

Other crude oils require more elaborate puriThe next award will be made in 1905, when fication (refining) before they are placed on six prizes will be offered for competition.

the market, Notable examples of this kind are cotton seed vil and rape oil. The sample several ozone processes, but although at the of Egyptian crude cotton seed oil I show here first moment they seemed to effect the bleachhas been expressed direct from the crushed ing satisfactorily, yet after a time the colour of seed. It ranges from a ruby red to almost black the oils darkened, or as the technical term runs, colour, due to the deep dark brown colouring “ reverted." matter contained in the cells of the cotton Bleaching by means of oxygen in statu seed. The oil is refined by treatment with nascendi is chiefly effected by employing mandilute caustic soda ; the latter combines with

ganese dioxide or potassium bichromate and the colouring matter and the free fatty acids sulphuric acid. in the oil and forms a precipitate which falls (2) In the processes of bleaching by means down on standing, leaving the oil clear and of chlorine, bleaching powder, or potassium bright. This crude rape oil, again, is refined bichromate and hydrochloric acid are used. by treatment with concentrated sulphuric acid, No general rule can be laid down as to which and yields the refined oils shown here. From process should be employed in each given case, these two examples, which can be multiplied although it may be stated that tallow is best by the series of other oils which you have bleached by means of manganese dioxide, and before you, both in the crude and refined palm oil by means of bichromate and hydrostate (linseed, castor, fish, sperm oils, and chloric acid. various rape oils, &c.), it may be gathered The object of bleaching is not only to remove that the processes adopted on a manufac. colouring matters for the time being, but to turing scale vary greatly with the nature of remove them so efficiently that the colour, or each individual oil or fat.

even a dark shade, will not “revert" some The methods of bleaching or decolourising time after the fat or oil has been bleached. oils also vary with each kind of oil or fat. Patents claiming to effect this object appear Time permits only of a brief glance at the annually in great numbers, and disappear methods employed on a large scale.

again when experience has shown that the Bleaching by sunlight, one of the oldest colouring matter does “re vert” to a larger or processes, is naturally only feasible on a small smaller extent after the material has, e.g., scale, as the length of time and the space been converted into soap. Thus one of the required to expose as large a surface as simplest and most frequently practised propossible must naturally be costly. Still, in cesses, that of bleaching tallow, does not prosome cases, as in the bleaching of beeswax or duce soaps as good in colour as those made in the bleaching of linseed oil for artists' use, from the freshly rendered tallow. Not only this method is being practised. Since the must each kind of fat or oil be considered fatty matter undergoes practically no change, a special problem, but frequently different the products do not suffer as much as they varieties of one and the same oil are apt to would in the chemical processes of bleaching. cause the same difficulties as would a new

Bleaching by the aid of chemicals requires oil or fat. To mention an example, the great circumspection, the object of bleaching bleaching of the softer kinds of palm oil, such being merely to destroy foreign substances, Lagos “Old Calabar," offers very which impart a dark colour, or other undesir- little difficulty. But the harder kinds of palm able properties to the oil or fat. The chief oil, such as Congo oil, have hitherto withstood attention of the operator must therefore be all attempts to bleach them. directed to so treating the raw material that The above methods of bleaching are, howthe fatty matter itself is not acted upon. For ever, inadmissible in the case of those oils this purpose, the amount of chemicals must be and fats which are tendered for edible pur. limited to the smallest possible quantity, the poses. In these cases we must rely chiefly on temperature at which they are allowed to act physical methods. The oils intended for edible must be as low as possible, and the time of in- purposes must not even be expressed while teraction must be as short as possible.

hot, and the employment of chemicals inGeneral methods of bleaching chemically, volving the use of acids must be altogether are-(1) Bleaching by means of oxygen ; (2) excluded, as they impart an objectionable bleaching by means of chlorine.

flavour which would render the product useless (1) Bleaching by means of

oxygen for edible purposes. Treatment with alkalis gas is still too uncertain a process to be widely in one form or another can only be resorted used on a large scale, and is only practised to in a very moderate degree as, for instance, in some special instances. I have examined in the refining of cotton seed oil for the table.

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