The Victorian Government prize essays, 1860

Contents

/N/\Art/NA/\A/\A/\Z>A/W\/\AAAA/M

Page

Pbeface V

Preface

During last year the following notification was made public : —

ROYAL SOCIETY OE VICTORIA.— GOVERNMENT PRIZE

ESSAYS, 1860.

The Council of the Royal Society of Victoria has to announce that the Government has placed at the disposal of the Council the sum of Six hundred pounds sterling, voted by the Legislative Assembly as Premiums for Essays. The Council has decided, with the sanction of the Government, that the premium to be awarded for the best Essay on each subject shall he One hundred and twenty-five pounds sterling, with a medal. The following subjects have been selected, viz. : —

1. On the Collection and Storage of Water in Victoria for Gold- Wash-

ing, Irrigation, Motive-Power, and General Water Supply; with reference also to the practicability of Artesian Wells in certain localities.

2. On Agriculture in Victoria, with special reference to the Geological

and Chemical Character of Soils, to the Rotation of Crops, and to the Sources and Application of Manures.

3. On the Origin and Distribution of Gold in Quartz -Veins, and its

Association with other Metals and Minerals, and on the most improved Methods for extracting Gold from its Matrices.

4. On the Manufactures more Immediately Required for the Economical

Development of the Resources of the Colony, with special reference to those Manufactures the raw materials of which are the produce of Victoria.

Competitive Essays on the above subjects are required to be written in a legible hand, on foolscap paper, on one side only, and leaving a two-inch margin. The authors will attach mottos only to the Essays, and accompany each Essay with a sealed envelope, containing inside the name and address of the author, and on the outside the motto affixed to the Essay.

VI

The Essays must be iu the hands of the Honorary Secretary of the Royal Society on or before the 1st of October, 1860.

The Council will appoint, subject to the approval of Government, three judges, who may or may not be members of the Society, to decide on the respective values of the competitive Essays on each of the four topics named ; but the Council reserves the power to withhold the premium in the case of any of the subjects, should the competitive Essays on that subject be considered unworthy of such a reward.

The Essays receiving premiums shall be considered the property of the Government.

Royal Society, Victoria-street,

Melbourne, March 28, 1860.

In accordance with this notification, Essays to the number of twenty-six were forwarded to the Royal Society, and after careful examination the following were adjudged to be the successful ones.

During the progress of these Prize Essays through the press, numerous and valuable additions were made by the Authors to the original text. In justice to the other competitors, these additions are printed in a different type, and take the form of appendices. The foot notes formed part of the original MSS. Several maps, woodcuts, and tabulated statements have also been introduced to elucidate the various subjects. These circumstances have combined to delay the publication of the Essays until a later period than was originally anticipated.

The subjects treated of in the Essays which follow relate to the further development or more economical use of the principal natural resources of the colony. While some of these have been already so fully realized as to have placed Victoria in a commanding position, it can scarcely be denied that others admit of still further development, and indeed demand vu attention, if the progress of the country is to be at all commensurate in the future with that which has marked it during the last few years. Moreover, as increase of population requires that new sources of industry should be made known, these Essays are further designed to indicate the direction in which such sources may be found, by those whose unemployed labor or capital seek for a fresh outlet for profitable investment.

The first Essay treats of the collection and economical use of the Water Supply of the country, so as to render it more available than now, for the gold miner, the agriculturist, the manufacturer, and for general domestic and sanatory purposes. Bv collecting and storing the frequently superabundant waters, so as to ensure a more constant and less costly supply, valuable assistance will be given to existing industrial pursuits, many of which fail at present to be permanent and profitable mainly for want of this desideratum.

The second Essay is occupied with the Geological, and, to a certain extent, the Chemical Characters, &c., of the various Soils of the country, a correct knowledge of which alone can enable the agriculturist to carry on his operations with certainty of success when the original qualities of the soil have been exhausted, and it becomes necessary to add fertilizing agencies. To those (and they are many) whose farming operations are now conducted empirically, this Essay will be read with pleasure, and it is anticipated that the principles laid down in it may be followed with advantage.

The third Essay deals with an important branch of Gold Mining enterprise ; and while, to some extent, necessarily

Vlll taken up with discussing the theories as to the formation of Quartz Veins, it yet enters into practical details which cannot fail to be of benefit to those engaged in quartz-mining pursuits, enabling them to conduct their operations with more economy, and to utilise what has often been hitherto considered the refuse of the mines, because of ignorance of its value, or the proper method of treating it with advantage.

The fourth Essay is occupied with the consideration of the Manufactures which may be necessary for the economical development of such resources as have been as yet but partially recognized in Victoria.

A proper degree of attention to the several matters treated of in these Essays will to some extent enable those, whether in Victoria or at a distance, who possess either knowledge or capital, or both, to judge of the fitness of Victoria as a field for the employment of labor or the investment of capital.

It is to be hoped, in conclusion, that this effort on the part of the Legislature will incite to a more careful study, and a more economical use of those vast resources which require but science and industry to develop, and that Victoria may become celebrated not only for her inexhaustible mineral wealth and fertile soil, but also for superior local manufactures and the quality of the raw materials she is destined to supply so largely for the industry of other countries.

JOHN MACADAM, M.D.,

Honorary Secretary to the Hoy at Society of lectori a.

i

ON TIIE

Collection and itorap of 18afp

IN VICTORIA.

BY FREDERICK ACHESON, C.E.

B

ESSAY.

The development of the ample resources of this colony demands at the present time the most serious and careful attention. The fact that industrial pursuits have of late not yielded that large return of former years, indicates either that the natural resources have been diminished, or that the means of developing' them are insufficient : the production of mineral wealth is dependent upon a precarious supply of water, which, in the most favorable years, is inadequate. The gold fields, long since stripped of their richer deposits, now present openings where only real industry, combined with ample appliances, will make them productive, while a vast extent of poor auriferous country remains deserted and unworked, which would yield profitable results from the judicious supply of water. That the yield of gold would be enormousl}r increased is undoubted and admitted on all sides, while the capital invested would he highly reproductive, and that without taxing mininginterests to any sensible extent, as the general surface of the auriferous districts is highly favorable for obtaining ample supplies of water for artificial storage both from its undulating and impervious nature, while in its general configuration abundant sites for reservoirs of large capacity are presented,' which, in many cases would involve but little outlay in their construction. It is satisfactory to know that, notwithstanding the diminished rainfall, an ample supply will be always available for collection, if only from the contribution of periodical heavy rains which happen during the driest years. The question of water supply becomes thus practically limited to economical storage capabilities. This colony has a mean rainfall, scarcely inferior, if not fully equal to that of England, whose more favorable geological formations modify the flow of water so as to distribute it permanently throughout the

PRIZE ESSAY.

year. In Victoria the rain falls upon a generally impervious surface unsuited to its absorption, and hence passes rapidly to the sea, leaving1 the beds of watercourses dry for a certain part of the year. How to prevent this enormous loss which forms a serious drawback to mining-, agricultural, and pastoral interests, forms a question of the highest importance to the industrial advancement of the colon)'-.

KAINFALL.

The observations on the rainfall of Melbourne have been conducted firstly, during the years from 1846 to 1851 inclusive, by Mr. Archer ; the mean result for the six years was 32 inches per annum, the lowest being 26 inches for the year 1847, and the highest 44| inches for the year 1849, in the November of which there fell so much as 12 inches. The results obtained during the years 1855, 1856, and 1857, at the Surveyor- General’s office, were nearly the same for each, being 28f inches.

Professor Neumayer’s observations from March, 1858, to February, 1859, give a mean rain for Melbourne of 21 \ inches, and from March, 1859, to February, 1860, 21f inches.

The following table shews the results of observations throughout the colony hitherto published : —

Year.

Melbourne.

Geelong-.

Williamstown.

Heathcote.

Yan Yean.

Ballaarat.

Beechworth.

Castlemaine.

Camperdown.

Portland.

Sandhurst.

Port Albert.

to y to y to y to y

Sept. 1860 J

mean of 8 mths.

28 59 28-55 21-69

21-72

1-70

mean

pr.mth.

mean for 11 months 203

21-79

20-31

23-78

27-50

24-47

30 87

19-54

27-97

27-30

mean lor 11 months 2-24

mean for 8 months 2-89

COLLECTION AND STORAGE OF WATER.

From this table it appears that not only there has been a considerable diminution in the amount of rainfall of late years in Melbourne, but also that the last two 3rears of observation were unusually dry.

As the average rain of the interior, where observed, was over 05 inches during a year of this dry period, this amount may safely be assumed as within the general average, and sufficiently safe to base calculations of least supply upon.

This rainfall gives a mean result of 381,668,000 tons of water per day over the whole area of the colony.

AVAILABLE RAIN, DRAINAGE BASINS, Ere.

The proportion of this rain that drains off the surface, and thence by the watercourses reaches the sea, being the available rainfall, forms a most important feature in this inquiry, and is one unfortunately that has never been determined by any extended series of experiments ; some light, however, may be thrown upon this subject by investigating* the conditions of surfaces forming drainage basins relatively with the known or deduced discharges of water therefrom.

The disposal of the rainfall upon its descent upon the surface may be classed as follows : firstly, by surface moisture and evaporation ; secondly, by absorption and filtration through porous formations originating springs ; thirdly, by surface drainage into the watercourses forming the main portion available for collection and storage. The relative proportions of rainfall disposed in each case necessarily depends upon the geological nature and configuration of the receiving basins, a due consideration of which is all-important in investigating the sources of water supply.

A large proportion of the colony consists of sandstone and slate formation, highly contorted from upheaval, and covered frequently with vast plains of basalt, especially towards the west, and protruded by large masses of plutonic rock, principally towards the east.

The general surface of this 'formation is of an impervious, non-absorbent character, being covered with a stiff clay, the result of its own decomposition, and also with beds of cemented gravel and sand of a generally very impervious nature.

I he immense area occupied by this formation as the surface

PRIZE ESSAY.

rock, and its necessarily undulating- and steep character, combine with its superficial imperviousness to effect the rapid discharg-e of a larg-e per-centag-e of the rain into the watercourses, and thence to the sea, at once causing- destructive floods and subsequent drought from the sudden and intermittent nature of the discharge.

But while to this formation, consequently almost destitute of springs, may be mostly attributed the non -permanency of the streams, and the badly watered condition of a large portion of Victoria, it nevertheless forms the best gathering grounds for the collecting- and storage of water, and discharges off its surface the largest per centage of rainfall, and is therefore well adapted in an economical point of view for the supply of storage reservoirs, which may therefore in this formation be constructed of smaller capacity than those fed from more porous basins.

Although it may be said that this formation has comparatively little capacity for absorbing water, and giving it out gradually in the form of springs owing- to its retentive character, yet the beds of its leading valleys and watercourses are frequently covered with an alluvium of sandy clay and gravel of a highly absorbent character, resting immediately upon the surface of the rock and affording- abundant supplies of water by sinking even in the dry seasons. To this source are the gold-fields frequently indebted for a supply of water during- the summer months ; the absorbent character of the alluvium effecting a capacity for the storage of water therein invaluable to the miner during the dry season, although presenting difficulties to mining operations during the winter.

Next to the clay-slate and sandstone formation the basalt plains occupy the largest area, covering a large proportion of the western half of Victoria: owing to their level character they discharge a comparatively small per centage of rainfall into their watercourses, which are few and far apart ; being covered with a tolerably stiff clay the}r are not well adapted for absorption, hence a considerable amount of the rainfall rests upon the surface and is disposed in the form of swamps and lagoons having no outlet and subject to constant evaporation.

The counties of Ripon and Hampden consist almost exclusively of trap plains, and evidence by their comparative absence of minor watercourses the small amount of water drained off them into the creeks. A considerable area of the latter county is covered with

COLLECTION AND STORAGE OF WATER.

an immense number of lagoons and swamps which testify at once the general non-absorbent character of the soil and the small capacity of the basalt plains for surface drainage, The fact also that the creeks intersecting this formation although frequently along deep valleys have comparatively few and unimportant springs, insufficient in the dry season to effect a constant How in the creeks, and whose localitv is scarcelv otherwise indicated than by the presence of salt in the waterholes, evidently the result of salt-springs from the basalt, testify to its meagre absorbent capacity. The general paucity of springs from the basalt formation is further evidenced by the generally dry beds of its creeks in the summer time, intersecting as they frequently do one hundred miles of eountrv at levels considerably below the general surface of the plains, they could not fail to drain a regular and uniform supply of water from this formation were it stored therein to any considerable extent.

That, however, copious springs occasionally occur in this rock is apparent from the examples at Mount Rouse, in the county of Villiers, and at the source of the River Coliban ; these however are probably the result of great volcanic action producing a more decidedly fissured character in the rock than in that of the basalt plains.

The primitive granitiform formations of Victoria form a most important feature in its geological structure, as being the source of nearly all the permanent streams, forming a considerable portion of the great dividing range, from Mount Disappointment eastwards,- from them proceed the only truly permanent streams in the colony, embracing the rivers Mitta-Mitta, Little River, Ovens, Goulburn, and Yarra, with their tributaries, flowing to the north and west, together with the magnificent rivers of Gipps Land flowing towards the south.

The peculiar aptitude of these rocks for the storage of rain water, and its gradual emission was observed at the sources of the River Plenty in Mount Disappointment, and arises from the lodging of the water in its extensive fissures, while the surface of the rock is covered with a spongy decomposed vegetable soil, constantly generating fresh vegetation, the subsequent decay of which increases the peaty mass which is thus constantly accumulating; rain falling upon this spongy surface is readily absorbed and filtered through into the fissures beneath, from wdience it but slowly

PRIZE ESSAY.

drains out at lower levels, from the external fissures being- filled up with this spongy soil, and roots of plants, &c. The eastern source of the Plenty, when observed in the summer of 1855, delivered 12 cubic feet per second, solely under the above conditions. The Woori \ alloak Creek, a small tributary of the Yarra, only 20 feet wide, and supplied from spring's in the Dandenong and adjacent ranges eastward, discharged in the summer of 1859, 50 cubic feet per second, (or about one-tenth of the whole Yarra discharge on same day at Melbourne), from similar sources, as it was not then (if at any time) affected h}7- the melting of snow, or bv sui-face drainage ; and this creek forms a tjrpe, in an inferior degree, of the many constantly flowing tributaries of the Yarra, such as the River Don, Badgers’ Creek, Running Creek, &c. ; all of them, in the dry season, evidently the sole result of springs fiom gianitiform rocks, and not from the melting- of snow, wRich if it existed in the height of summer, could be easily seen on the exposed Dandenong-, Plenty and other ranges, forming the sources of these streams.

But while to this cause may be attributed the permanent character of streams generally, another scarcely less important source of supply is derived from the melting- of snow on the Australian Alps, during the spring; the Mitta-Mitta, Little River, Ovens, and Goulburn, tog-ether with the principal rivers of Gipps Land, are all considerably affected from this cause, and are subject to sudden and heavy floods from the effects of a few warm days in the spring, suddenly melting- the snow on the rang-es ; although this result is comparatively irrespective of the nature of the formation on which the snow rests. Yet the continuity of the supply from this source will depend, more or less, upon the porous character of the formation on which the snow rests, causing its absorption according- as melted, and thus storing- it, so as to effect a gradual flow ; it is thus that the snow upon the Australian Alps combines with the fissured character of the granitiform rocks on which it is deposited, to produce a greater continuity and uniformity of flow, than if the surface formation were of a more impervious nature.

The Australian Alps, with their extensive spurs, extending far northwards and southwards, under these conditions, and traversing as they do, more than one hundred miles in length in Victoria, thus naturally form the source of an immense supply of wrater,

COLLECTION AND STORAGE OF WATER.

which is to a considerable extent stored within their fissures, and given out gradually in the dry season, after the melting of the snow has ceased; this fact is abundantly proved by the measurements of discharge taken by the Survey Department of Victoria in February of the present year ; the aggregate discharge southward into Gipps Land, with the exception of the Snowy River, amounted to 1600 cubic feet per second, while that to the northward and westward from the Mitta-Mitta to the Yarra, resulted in 2580 cubic feet per second in December of last }rear; these results making together 4180 cubic feet taken in the dry season, when the melting of the snow must have ceased, (excepting on the highest altitudes), and thus representing only the residue drainage, would form a combined stream, fully equal to the summer How of the River Murray below the Goulburn.

With such an amount of water obtainable from this source during the dry season it is reasonable to calculate upon a vastly greater quantity as representing the whole annual flow therefrom, a great proportion of which is carried away upon the sudden melting’ of the snow, in heavy floods, as is evidenced by the rapid rising of the rivers, frequently up to 18 feet in a few hours, on the first approach of a few warm days in the spring’.

It may at least, therefore, be assumed with tolerable certainty, that the Australian Alps, with their connected ranges, occupying an immense area in Gipps Land and the Murray District, form a source of water supply amply sufficient for the whole surface of the colony for all useful purposes.

The practicability of the disposal of a portion of this vast natural supply in the form of central westerly streams, capable of commanding at high levels a large area of Victoria, forms a subject worthy of the deepest consideration, fraught as it is with such importance to the development of all the material resources of the colony; nor should the apparently insurmountable difficulties that present themselves to the execution of such a great work deter searching investigation into its merits. So high an authority as the Surveyor-General has, indeed, already propounded a scheme somewhat similar, and of as great magnitude : in the absence of preliminary surveys, however, it would be premature to decide definitely on the subject.

As the River Yarra forms a sample of the above class of streams, all of which drain from basins similar to its own in

PRIZE ESSAY.

geological character, an examination into the capacity and nature of its basin relatively with the amount of water drained therefrom, will be important in determining the value of such basins generally for the production of permanent streams, and also their capacity for the collection of rain.

This river is contained in a basin of about 1500 square miles, comprised in the southern slopes of the great dividing- range on the north, and an extensive spur therefrom on the south and east.

The supply of water is derived principally from two sources : — firstly, rain upon the impervious portions of the basin, comprising the clay-slate, sandstone, and trap formations, which, with the exception of the latter, being generally precipitous, and having little capacity for retaining the rain water falling on them, it flows off, after surface saturation, into the watercourses, the sudden and simultaneous discharge of which into the river causes swellings and floods of more or less magnitude, dependent on the relative amount of rain in a given time and its duration ; the other source of supply comes from that area of its basin occupied by the granitic and porphyritic rocks abounding in fissures, and clothed with dense vegetation, and thus having a vast storage capacity for the rain water falling on them, hold back a considerable supply, which is given out gradually by means of a great number of constantly flowing streams of water of great purity.

The geological formations of the basin of the Upper Yarra being as yet unsurveyed, it is impossible to arrive at the relative proportion of the granitic and porphyritic rocks to the clay-slate and others, throughout the whole, which has only been investigated for a distance of forty miles eastward of Melbourne ; however, the area of granitic and porphyritic rock, as yet ascertained, amounts to about one hundred square miles, of which the granite at the source of the Plenty alone occupies about ten square miles, and discharges from its fissures in the dry season, when all surface drainage has ceased, about sixteen cubic feet per second, in addition to the discharge on the north side of the range, forming the source of the Sunday Creek.

It is certain, however, that the granitiform rocks do occupy a considerable area in the basin of the Upper Yarra, as it lies mostly on the great dividing range and spurs which consist almost entirely of these rocks, whose presence is further indicated by the number of constantly running streams proceeding therefrom.

COLLECTION AND STORAGE OF WATER.

The presence of these rocks in the eastern part of the great dividing’ range, forms an important geological feature, and renders the Yarra, in common with the Goulburn and the rivers of the Murray District and Gipps Land, exceptional to the generality of the streams of the colony, which, for the most part, owe their supply to surface drainage from an impervious watershed, supplemented occasionally by feeble springs. Thus the River Campaspe, below its junction with the Coliban, has a drainage basin of 500 square miles, or about one-third the area of that of the Yarra, and consisting almost wholly of slate, sandstone, and trap formations, having but a limited area of granite, and yet discharged at this point only 4| cubic feet per second, on the same day that the latter river gave 535 cubic feet. This fact, taken in connection with the ample rainfall on these high basins, forms a striking proof of the immense loss of water due to the absence of porous rocks, and to the generally impervious character of the prevailing formations in the colony, causing the rain either to be returned to the atmosphere by surface evaporation from level ground, or to be rapidly discharged into the watercourses in the form of floods after heavy rain upon steep ground, so that passing off in great volumes, no permanent flow is left more than what may be supplied by casual springs and drainage from swampy flats in the watercourses.

The area of the known clay-slate, sandstone, and trap rocks, in the Yarra basin, occupying nearly two-thirds of the whole, or about 1000 square miles (of which the trap covers one-eighth), is drained mostly by the non-permanent streams; only so much of the permanent ones receive its drainage as pass through it, while they derive their constant flow only from the porous rocks at their source. The discharge of the Yarra in the dry season does not include drainage off this area, its watercourses being then dry, excepting immediately after rain, hence the least or summer flow of the Tarra comes altogether from the remaining third part ot the basin. It is reasonable, therefore, to conclude that the amount of water drained into the Y. arra from off the former area of clay-slate, &c., during the year, forms at least two-thirds of that from ofl the whole basin, especially when the generally impervious and precipitous nature of the surface is considered, which is hence better adapted to collect and rapidly discharge the rainwater off into the creeks than more porous formations.

PRIZE ESSAY.

What the whole mean discharge of the Yarra is cannot be ascertained but by an extended series of observations, but as the least or summer flow is about 535 feet per second or 624,880,000 cubic yards per annum, derived solely fl-om granitiform formations, that from the above distinct area of clay-slate, &c., must, according* to the above conclusion, be at least twice this amount, or 1,249,760,000 cubic yards; the sum of these two will give 1,874,640,000 cubic }rards as the known least discharge per annum of the Yarra, at Melbourne, as thus estimated.

It is highly important to observe that this amount represents a depth of collected rain water of 14| inches over the Yarra basin of 1500 square miles, the summer flow alone being equivalent to nearly 4-8 inches depth of rain over the whole basin.

The following facts obtained from basins, analogous and similar to that of the Yarra, tend to confirm the approximate truth of this available collected rain.

The River La Trobe, in the month of February of this year (the driest month), discharged 674 cubic feet per second into Lake Wellington from off a drainage basin of 1900 square miles, equivalent to a depth of rain over the basin of 4-8 inches, being exactly the same as that in the Yarra basin from its summer flow.

The River Mitchell discharged into Lake King the same time (February, 1860) 497 cubic feet per second, its basin being 1800 square miles; this discharge represents a depth of rain thereon of 3i inches.

The discharge of the Mitta-Mitta in December, 1859, was 464 cubic feet per second from a basin of 2000 square miles, being equivalent to 3T inches of rain.

The Little River, draining from a basin of 700 square miles, next to that of the Mitta-Mitta, discharged into the Murray on the same day 161-8 cubic feet per second, representing a depth of collected rain of 3-1 inches, the same as the Mitta-Mitta adjacent.

The above results taken at periods subsequent to the melting of the snow at the heads of the rivers which were at their summer level, and unaffected by surface drainage, and as such representing but an inferior portion of the whole amount of water passing down annually, indicate a large mean per centage of rainfall as due from the gathering basins of the Murray and Gipps Land districts, which being of a generally hilly character facilitate the discharge of the surface drainage into the watercourses before

COLLECTION AND STORAGE OF WATER.

being evaporated from the soil, irrespective of that which is held back in the form of snow in the higher regions, and when melted maintains the saturation of the porous rocks forming the source of summer supply.

The collected rainfall of the west half of Victoria lies under more unfavorable conditions than that of the east above. The creeks rising generally in steep clay-slate and sandstone formations through which they traverse for a considerable part of their course, at length emerge upon and flow through vast basalt plains which occupy a large proportionate area of their basins, but contribute little drainage from off their surface ; so far as the creeks flow through the upper clay-slate part of their basins they are under the most favorable conditions for obtaining a large per centage of rainfall, and quite on a par with the rivers of (jipps Land and the Murray District, but there being no storage capacity -within their basins the great bulk of the water passes rapidly off and is lost for all useful purposes.