acreage with sewage, twelve crops of rape and other herbage are obtained per year, maintaining twenty sheep to the acre the year round. The plan is to breed and fatten sheep for the market, and for years in succession some of the very choicest are those from the Werribee Farm.

A sufficient sum is earned to pay interest on the cost of
land

£150,000

£400,000

And on cost of grading, machinery, wharf, drains, &c. . 250,000 I.e. interest is paid on a total crop of and the net profits for the last five years have been 32,000l. One is made to wonder why some such scheme has not been found practicable in London, where the population is thirteen times the size of Melbourne, and the possibilities proportionate; why the lowlands of the Essex Coast by which the London County Council fleet of sludge vessels ply could not be built up and utilised like the Werribee Farm on Port Phillip Harbour is difficult to understand. In any case as one has so often been met by the statement that 'it is impossible to deal with sewage in any known way to make a profit,' here is at last a case where, without any glossing of facts or figures, a genuine commercial success is made, and which is surely worthy of the attention of municipal authorities at home.

What may be expected to take place during the next decade in Australia? is a question asked by many who have been surprised at the coming to power of a Commonwealth Labour Ministry.

It is not wise to prophesy far in advance, especially as so much in this case depends upon what development takes place in Europe generally, and in the United Kingdom particularly. But amongst other changes may be expected the nationalisation of the tobacco industry, the opening up of the iron-ore deposits, the manufacture of iron and steel, and consequently a large increase in engineering and machine-making. In this connection a most important development has just taken place in Melbourne, where the manufacture of iron and steel from the magnetic iron sand of New Zealand—and this without the aid of a blast-furnace—is an accomplished fact, and the same principle can be applied to crushed iron ore. The iron-making industry will be taken in hand by one of the State Governments, and kept rigidly under State control. The resumption of the land by the States will be demanded with increasing force. State agriculture and horticulture will be initiated and developed. Land will be set apart for co-operative production, so as to afford scope for co-operative farming, and on lines that will afford opportunities for the unemployed.

Old-age pensions are not yet on a satisfactory basis; additions to the amount allowed, and a more generous manner of disbursing the same, will certainly be authorised.

Between the workers of Australia, Europe, and America there is rapidly developing a community of interest which will result in concerted action on all main social and industrial changes.

Fate has decreed that these Australian States shall be the forerunners in a really triumphant democracy, not on the lines set forth by Mr. Andrew Carnegie; for instead of the workers of America today occupying that position they are amongst the most exploited people on earth. Industrial warfare is there being waged by means of bullets and sabres, by the organised capitalist forces, for the express purpose of fighting down the workers and keeping them under capitalist subjection. The ranks of the unemployed are increasing rapidly in the United States, and their people are suffering because of a plethora of wealth.

The stupendous power of wealth production in America does not result in raising the standard of life of the workers, or in solving the problem of unemployment. The conditions in all countries under a capitalist régime are so unsatisfactory that the Australasian States are compelled to look forward to a Collectivist régime; this the workers believe to be inevitable, and this they are sensibly preparing for by peaceful and constitutional methods. Many of them are students of social economics, with no prejudice in favour of any system other than that obtained by education and observation of the world's affairs, and they have come to see the wisdom of John Stuart Mill's statement: The social problem of the future we consider to be, How to secure the greatest individual liberty of action, with a common ownership of the raw material of the globe, and the equal participation by all in the benefits of combined labour.'

Melbourne, Victoria: June 1904.

TOM MANN.

A CHAPTER ON OPALS

ASSUMING that intrinsic beauty and rarity are the characteristics which constitute a gem, then the precious or noble opal, as the best specimens of the opal are termed, is entitled to very high rank. At the present time Mr. Edwin Streeter, a considerable authority in everything relating to jewels and precious stones, places it fifth in the order of precedence, an arrangement which is apparently governed by the test of money value or price; because in setting pearl at the head of the list, he points out the great appreciation which has recently taken place in its marketable value, saying that pearls which twenty years ago were worth 60l. to 801. now fetch 500l. to 600l. This advance may be due to fashion, and, if so, has to be regarded apart from those cardinal traits of beauty and rarity which are herein accepted as the qualities that ought to determine us in forming a judgment upon the relative merit of gems. Mr. Streeter's table proceeds in the following order :-I. pearl, II. Burma ruby, III. diamond, IV. emerald, sapphire, oriental cat's eye, alexandrite, precious opal. To find diamond in the third place will be a surprise to many, but there are circumstances at work which, if continued, will relegate the diamond to a still lower position, notably the large production from the Kimberley and other South African mines, the ability to make real diamonds artificially, which, although as yet a difficult and costly operation, may be capable of development, and the ease with which brilliant imitations can be manufactured. These conditions apply also, but not with equal force, to the pearl, ruby, emerald, sapphire, and other gem-stones. With the precious opal it is otherwise.

It is on record that by the ancients it was counterfeited more successfully than any other jewel, so that with their tests it was nearly impossible to distinguish between the real specimens and their imitations. If so, the knowledge of this art has been lost, and modern attempts to revive it have ended in failure. It is almost beyond conception that anything possessing the indescribable and fascinating beauty of the finest types could be made by human skill. Therefore as it stands exempted from the danger of imitation, should the element of rarity persist, the noble opal seems likely to regain the exalted position it formerly held.

While not included in the somewhat comprehensive list of gems set by Moses in the breast-plate of Aaron the High Priest, or of those mentioned by the Prophets, and later by St. John the Divine, over whose mind precious stones appear to have exercised great imaginary sway (unless jasper, to which opal is allied, be taken as representative of opal), nevertheless the opalus of the Romans, omáλλios of the Greeks, and the Sanscrit upala, has a fair claim to antiquity. The affection which the ancients entertained for this lovely gem was unbounded. The Romans particularly held it in great esteem. 'Of all precious stones,' says Pliny, 'the opal is the most difficult to describe, since it combines in one gem the beauties of many species, the fire of the carbuncle, the purple of the amethyst, the green of the emerald, and the yellow of the topaz.' The same writer tells that the Senator Nonius possessed a valuable opal, about the size of a filbert nut, of which he was extremely fond. It was set in a ring, and its value, computed in the money of to-day, was 20,000l. At the instance of Mark Antony, who, it is alleged, coveted the gem and wished to obtain it, Nonius was proscribed and preferred banishment rather than surrender this treasure. In a curious old volume of the seventeenth century entitled A Lapidary the author thus expresses himself: 'The opal is a precious stone which hath in it the bright fiery flame of the carbuncle, the fine refulgent purple of the amethyst, and a whole sea of the emerald's green glory.' Another writes, "The tender violet of the amethyst, the blue of the sapphire, the green of the emerald, the golden yellow of the topaz, and the flashing red of the ruby appear at times in certain parts of the stone, crossing each other in vivid play with an effect that is magical.' And Boetius, 'The fairest and most pleasing of all other jewels by reason of its various colours.'

The cause of this play of colours in the precious opal, on which its trueness or nobility depends, has greatly exercised the scientific mind and given rise to many different opinions, but no entirely satisfactory reason has been forthcoming, although it has in recent times been investigated by Sir David Brewster, Sir William Crookes, and Lord Rayleigh. Thus far we have been considering only one description, viz. the precious or noble opal; there are many varieties, of which the following are the principal:

(1) Precious or noble opal, which exhibits brilliant reflections of green, blue, yellow, and red, the play of colours indicated above.

(2) Fire opal or girasol, presenting chiefly red reflections.

(3) Common opal, whose colours are white, green, yellow, and red, without the play of colours.

(4) Semi-opal, the tendencies of which are more opaque than common opal.

(5) Wood-opal, which shows a woody structure.

(6) Hydrophane, which assumes a transparency only when thrown

into water. This is a most interesting variety, of which more will be said.

(7) Hyalite, colourless, pellucid, or white.

(8) Cacholong, nearly opaque, of a bluish white colour.

(9) Jasper-opal, moss opal, asteria, and some others.

There are occasionally found specimens of black opal, which are very beautiful, exhibiting variegated colours on a black ground. These are rare and command very high prices.

All of them are composed of silica in the gelatinising or colloidal state, with more or less water, and occasionally, as accidental admixtures, other substances in small proportions. By analysis the following results have been found as regards the silica:

Opal may be regarded as an uncleavable quartz. Hardness 5.5 to 6.5, specific gravity 2:091. When first taken out of the earth it is not very hard, but by exposure to the air its hardness is increased; nevertheless it always remains a soft stone compared with other gems. More particularly now with regard to the species called Hydrophane, which is composed of

In its ordinary state it appears as a white or reddish yellow material, feebly translucent or completely opaque. But if it is plunged into water it disengages small bubbles of gas, and at the same time becomes transparent, sometimes displaying the colours of the true opal. Taken from the water this curious stone keeps its transparency for a time, but gradually, as the water evaporates, becomes once more opaque. The older mineralogists, considering this stone an unexampled marvel, named it 'Oculus Mundi,' the Eye of the World. Other kinds have the curious property of improving by the warmth of the hand, which brings out the brilliant tints for which the opal is so famed. In contrast to the Hydrophane, the remarkable gem introduced by Sir Walter Scott into his novel Anne of Geierstein, described as an opal, is said to have been utterly destroyed by a drop of water falling upon it. The water, however, was holy water, and the wearer of the jewel was strongly suspected of demoniacal possession, a combination likely to lead to some catastrophe.

Commercially, only three varieties of opal are recognised, viz. oriental opal, fire opal, and common opal. The term oriental was given to it by the Greek and Turkish merchants, who obtained it from Hungary and then carried it to the East for the purpose of