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PEINCIPLES OF MANURING 



MANURES 



AND THE 



PRINCIPLES OF MANURING 






BY 



C. M. AIKMAN, M.A., B.Sc., F.E.S.E, F.I.C. 

PROFESSOR OP CHEMISTRY, GLASGOW VETERINARY COLLEGE; 

EXAMINER IN CHEMISTRY, GLASGOW UNIVERSITY; 

AUTHOR OF 'FARMYARD MANURE,' ETC. 



WILLIAM BLACKWOOD AND SONS 

EDINBURGH AND LONDON 

MDCCCXCIV 



TO 

SIR JOHN BEMET LAWES, BAKT,, D.C.L, LL.D., F.B.S., 

OF ROTHAMSTED, 
AND 

SIR J. HENRY GILBERT, M.A., LL.D., F.R.S., 

FORMERLY SIBTHORPIAN PROFESSOR OP RURAL ECONOMY, 
UNIVERSITY OF OXFORD, 

WHOSE FAMOUS INVESTIGATIONS DURING THE LAST FIFTY YEARS 

HAVE SO LARGELY CONTRIBUTED TO BUILD UP 

THE SCIENCE OF MANURING, 

THIS WORK, 

EMBODYING MANY OF THE ROTHAMSTED RESULTS, 
IS DEDICATED. 



380432 



PREFACE. 



WHEN the present work was first undertaken there 
were but few works in English dealing with its 
subject-matter, and hardly any which dealt with 
the question of Manuring at any length. During 
the last few years, however, owing to the greatly 
increased interest taken in agricultural education, 
the demand for agricultural scientific literature has 
called into existence quite a number of new works. 
Despite this fact, the author ventures to believe that 
the gap which the present treatise was originally de- 
signed to fill is still unfilled. 

Of the importance of the subject all interested in 
agriculture are well aware. It is no exaggeration to 
say that the introduction of the practice of artificial 
manuring has revolutionised modern husbandry. In- 
deed, without the aid of artificial manures, arable 
farming, as at present carried out, would be impos- 



Vlll PREFACE. 

sible. Fifty years ago the practice may be said to 
have been unknown ; yet so widespread lias it now 
become, that at the present time the capital invested 
in the manure trade in this country alone amounts to 
millions sterling. It need scarcely be pointed out, there- 
fore, that a practice in which such vast monetary 
interests are involved is worthy of the most careful 
consideration by all students of agricultural science, 
as well as, it may be added, by political economists. 

The aim of the present work is to supply in a 
concise and popular form the chief results of recent 
agricultural research on the question of soil fertility, 
and the nature and action of various manures. It 
makes no pretence to be an exhaustive treatise 
on the subject, and only contains those facts which 
seem to the author to have an important bearing 
on agricultural practice. In the treatment of its 
subject it may be said to stand midway between 
Professor Storer's recently published elaborate and 
excellent treatise on ' Agriculture in some of ' its Re- 
lations to Chemistry ' a work which is to be warmly 
recommended to all students of agricultural science, 
and to which the author would take this opportunity 
of acknowledging his indebtedness and Dr J. M. 
H. Munro's admirable little work on ' Soils and 
Manures.' 

In order to render the work as intelligible to the 
ordinary agricultural reader as possible, all tabular 
matter and matter of a more or less technical nature 



PREFACE. ix 

have been relegated to the Appendices attached to 
each chapter. 

The author's somewhat wide experience as a Uni- 
versity Extension Lecturer, and as a Lecturer in con- 
nection with County Council schemes of agricultural 
education, during the last few years, induces him to 
believe that the work may be of especial value to 
those engaged in teaching agricultural science. 

He has to express the deep obligation he is under, 
in common with all writers on Agricultural Chemis- 
try, to the classic researches of Sir John Bennet 
Lawes, Bart., and Sir J. Henry Gilbert, now in pro- 
gress for more than fifty years at Sir John Lawes' 
Experiment Station at Eothamsted. His debt of 
gratitude to these distinguished investigators has 
been still further increased by their kindness in per- 
mitting him to dedicate the work to them, and for 
having been good enough to read portions of the work 
in proof. In addition to the free use which has been 
made throughout the book of the results of these 
experiments, the last chapter contains, in a tabular 
form, a short epitome of some of the more important 
Eothamsted researches on the action of different 
manures. 

To the numerous German and French works on the 
subject, more especially to Professor Heiden's encyclo- 
paedic 'Lehrbuch der Dlingerlehre' and the various 
writings of Dr Emil von Wolff, the author is further 
much indebted. 



x PREFACE. 

Among English works he would especially mention 
the assistance he has derived from the writings of 
Mr E. Warington, F.E.S., Professor S. W. Johnson, 
Professor Arrnsby, the late Dr Augustus Voelcker, 
and others. He would also tender his acknowledg- 
ments to the new edition of Stephens' ' Book of the 
Farm/ and he has to thank its editor, his friend Mr 
James Macdonald, Secretary to the Highland and 
Agricultural Society of Scotland, for having read 
parts of his proof-sheets. 

It is also his pleasing duty to thank his friends 
Dr Bernard Dyer, Hon. Secretary of the Society 
of Public Analysts; Dr A. P. Aitken, Chemist to the 
Highland and Agricultural Society of Scotland ; Pro- 
fessor Douglas Gilchrist of Bangor ; Mr F. J. Cooke, 
late of Flitcham ; Mr Hermann Yoss of London ; and 
Professor Wright of Glasgow, for having assisted him 
in the revision of proof-sheets. 

ANALYTICAL LABORATORY, 

128 WELLINGTON STREET, GLASGOW, 

January 1894. 



CONTENTS. 



PART I. HISTORICAL INTRODUCTION. 

PAGE 

Beginning of agricultural chemistry ...... 4 

Early theories regarding plant-growth 4 

Van Helmont ......... 4 

Digby 6 

Duhamel and Stephen Hales ...... 8 

Jethro Tull 9 

Charles Bonnet's discovery of source of plants' carbon . . 11 
Researches of Priestley, Ingenhousz, Se'ne'bier, on assimilation 

of carbon H-12 

Publication of first English treatise by Earl Dundonald . . 13 
Publication of Theodore de Saussure, * Chemical Researches on 

Vegetation,' 1804 . . .14 

Theories on source of plant-nitrogen . . . . .15 

Early experiments on this subject 16 

Sir Humphry Davy's lectures (1802-1812) .... 17 

State of agricultural chemistry in 1812 . . . . .17 

Beginning of Boussingault's researches (1834) .... 21 

Publication of Liebig's first report to the British Association . 24 
Refutation of " humus" theory ..... 26 

Liebig's mineral theory ....... 26 

Liebig's theory of source of plants' nitrogen ... 27 

Publication of Liebig's second report to British Association . 30 

Liebig's services to agricultural chemistry . . .31 

Development of agricultural research in Germany ... 32 

The Rothamsted Experiment Station ..... 33 



Xll CONTENTS. 

Sir J. B. Lawes and Sir J. H. Gilbert, the nature and value of 
their experiments 33 

Review of the present state of our knowledge of plant-growth 36 
Proximate composition of the plant . . . . .36 

Fixation of carbon by plants . . . . . .37 

Action of light on plant-growth, Dr Siemens' experiments 38 
Source of oxygen and hydrogen in the plant . . 39-40 

Source of nitrogen in the plant . . . . .40 

Relation of the free nitrogen to leguminous plants . 42-44 

Relation of nitrogen in organic forms, as ammonia salts, 
and nitrates to the plant ..... 46-50 

Nitrification and its conditions ...... 51 

Ash constituents of the plant ...... 53 

Methods of research for ascertaining essentialness of ash 

constituents of plants 53 

(a) Artificial soils, (6) water-culture .... 53-55 

Method in which plants absorb their food-constituents . 55 
Endosmosis . . . . . . . . .55 

Retention by soils of plant-food ..... 57 

Causes of retention by soils of plant-food .... 59 

Manuring ......... 60 

" Field " and " pot " experimentation .... 60 



PART II. PRINCIPLES OF MANURING. 

CHAPTER I. FERTILITY OF THE SOIL. 

What constitutes fertility in a soil ...... 65 

I. Physical properties of a soil . . . . . .66 

Kinds of soils ......... 67 

Absorptive power for water of soils ..... 67 

Absorptive power for water of sand, clay, and humus . 68 
Fineness of particles of a soil . . . . . .69 

Limit of fineness of soil-particles . . . . .69 

Importance of retentive power . . . . . .70 

Power of plants for absorbing water from a soil, experi- 
ments by Sachs ........ 73 

How to increase absorptive power of soils . . . .74 

Amount of water in a soil most favourable for plant growth 75 
' Hygroscopic power of soils . . . . . .75 

Capacity of soils for absorbing and retaining heat . . 76 



CONTENTS. Xlll 

Explanation of dew ....... 77 

Heat of soils 78 

Heat in rotting farmyard manure 78 

Causes of heat of fermentation . . . . .79 
Influence of colour on heat-retaining power ... 80 

Power of soils for absorbing gases 81 

Gases found in soils . . . . . . .81 

Variation in gas-absorbing power of soils ... 82 
Absorption of nitrogen by soils ..... 82 

Requirements of plant-roots in a soil . . . .83 

Influence of tillage on number of plants in a certain area 86 

Comparison of English and American farming . . 86 

II. Chemical composition of a soil ...... 87 

Fertilising ingredients of a soil . . . . . . 87 

Importance of nitrogen, phosphoric acid, and potash in a 

soil 88 

Chemical condition of fertilising ingredients in soils . 89 
Amount of soluble fertilising ingredients in soils . . 90 
Value of chemical analysis of soils . . . . .90 

III. Biological properties of a soil ... 92 

Bacteria of the soil . .... 92 

Recapitulation of Chapter I , .96 



APPENDIX TO CHAPTER I. 

NOTE 

I. Table of absorptive power of soil substances by Schiibler . 98 
II. Table of rate of evaporation of water in different soils by 

Schiibler 99 

III. Table of hygroscopic power of soils dried at 212 F. 

(Davy) 99 

IV. Gases present in soil . . . . . . .100 

V. Amount of plant-food in soils . . . . . .100 

VI. Chemical composition of the soil 101 

VII. Forms in which plant-foods are present in the soil . . 107 



CHAPTER II. FUNCTIONS PERFORMED BY MANURES. 

Etymological meaning of word manure 109 

Definition of manures .... 

Different classes of manures ... .111 

Action of different classes of manures 113 



XIV CONTENTS. 



CHAPTER III. POSITION OF NITROGEN IN 
AGRICULTURE. 

The Rothamsted experiments and the nitrogen question . . 115 

Different forms in which nitrogen exists in nature . . .116 

Relation of "free" nitrogen to the plant . . . .117 

Combined nitrogen in the air . . . . . .118 

Amount of combined nitrogen falling in the rain . . 119 
Nitrogen in the soil . . . . . . . .120 

Nitrogen in the subsoil . . . . . . .121 

Nitrogen of surface-soil 121 

Amount of nitrogen in the soil . . . . . .123 

Soils richest in nitrogen 123 

Nature of the nitrogen in the soil . . . . .124 

Organic nitrogen in the soil . . . . . .125 

Differences of surface and subsoil nitrogen . . .126 
Nitrogen as ammonia in soils . . . . . .127 

Amount of ammonia in soils ...... 127 

Nitrogen present as nitrates in the soil . . . .128 

Position of nitric nitrogen in soil . . . . .128 

Amount of nitrates in the soil . . . . . .129 

Amount of nitrates in fallow soils 129 

Amount of nitrates in cropped soils . . . . .130 
Amount of nitrates in manured wheat-soils . . . 131 

The sources of soil-nitrogen 131 

Accumulation of soil-nitrogen under natural conditions . 133 
Accumulation of nitrogen in pastures . . . .134 

Gain of nitrogen with leguminous crops . . . 1 35 

The fixation of " free " nitrogen ..... 136 

Influence of manures in increasing soil-nitrogen . . 136 
Sources of loss of nitrogen . . . . .137 

Loss of nitrates by drainage . . . . . .137 

Prevention of loss of nitrogen by permanent pasture and 
"catch-cropping". . . . . . . .138 

Other conditions diminishing loss of nitrates . . .139 
Amount of loss of nitrogen by drainage . . . .140 

Loss of nitrogen in form of " free " nitrogen . . .141 
Total amount of loss of nitrogen . . . . .142 

Loss of nitrogen by retrogression .... 

Artificial sources of loss of nitrogen . . . . .144 

Amount of nitrogen removed in crops . . . .144 



CONTENTS. XV 

Losses of nitrogen incurred on the farm . . . .146 

Loss in treatment of farmyard manure . . . .146 

Nitrogen removed in milk . . . . . .147 

Economics of the nitrogen question . . . . .147 

Loss of nitrogen-compounds in the arts . . . .148 

Loss due to use of gunpowder . . . . . .148 

Loss due to sewage disposal . . . . . .149 

Our artificial nitrogen supply . . . . . .150 

Nitrate of soda and sulphate of ammonia . . . .150 

Peruvian guano . . . . . . . .151 

Bones 151 

Other nitrogenous manures . . . . . .152 

Oil-seeds and oilcakes . . . . . . .153 

Other imported sources of nitrogen ..... 153 

Conclusion ......... 153 

APPENDIX TO CHAPTER III. 

NOTE. 

I. Determination of the quantity of nitrogen supplied by 
rain, as ammonia and nitric acid, to an acre of land 
during one year ........ 155 

II. Nitrogen in soils at various depths . . . . .156 

III. Nitrogen as nitrates in cropped soils receiving no nitro- 

genous manures, in Ib. per acre (Rothamsted soils) . 157 

IV. Nitrogen as nitrates in Rothamsted soils . . .157 
V. Examples of increase of nitrogen in Rothamsted soils 

laid down in pasture ....... 158 

VI. Loss by drainage of nitrates ...... 158 

VII. Examples of decrease of nitrogen in Rothamsted soils . 159 
VIII. Amount of drainage and nitrogen as nitrates in drainage- 
water from unmanured bare soil, 20 and 60 inches deep 160 



CHAPTER IV. NITRIFICATION. 

Process of nitrification . . . . . . . .161 

Occurrence of nitrates in the soil . . . . . .162 

Nitre soils of India . . . . . . . . .162 

Saltpetre plantations . . . . . . .163 

Cause of nitrification . . . . . . . .165 

Ferments effecting nitrification . . . . .167 

Appearance of nitrous organisms . . . . .168 

Nitric organism . . . . .169 



XVI CONTENTS. 

Difficulty in isolating them 169 

Nitrifying organisms do not require organic matter . .169 

Conditions favourable for nitrification 

Presence of food-constituents . . . . . .170 

Presence of a salifiable base . . . . . .171 

Only takes place in slightly alkaline solutions . . .172 

Action of gypsum on nitrification 173 

Presence of oxygen 173 

Temperature . . . . . . . . .175 

Presence of a sufficient quantity of moisture . . .176 
Absence of strong sunlight . . . . . .176 

Nitrifying organisms destroyed by poisons . . .176 

Denitrification . .177 

Denitrification also effected by bacteria . . . .178 
Conditions favourable for den itrifi cation . . . .178 
Takes place in water-logged soils 179 

Distribution of the nitrifying organisms in the soil . . .179 
Depth down at which they occur . . . . .180 
Action of plant-roots in promoting nitrification . . .181 
Nature of substances capable of nitrification . . .181 

Rate at which nitrification takes place . . . . .183 

Nitrification takes place chiefly during summer . . 183 

Process goes on most quickly in fallow fields . . .184 
Laboratory experiments on rate of nitrification . . .185 
Certain portions of soil - nitrogen more easily nitrifiable 
than the rest ........ 187 

Rate of nitrification deduced from field experiments . .187 
Quantity of nitrates formed in the soils of fallow fields . 188 
Position of nitrates depends on season .... 188 

Nitrates in drainage- waters . . . . . .188 

Amount produced at different times of year . . .189 
Nitrification of manures . . . . . . .190 

Ammonia salts most easily nitrifiable . . . .191 

Sulphate of ammonia the most easily nitrifiable manure . 191 
Rate of 'nitrification of other manures . . . .192 

Soils best suited for nitrification . . . . .192 

Absence of nitrification in forest-soils . . . .193 

Important bearing of nitrification on agricultural practice . 193 
Desirable to have soil covered with vegetation . . .194 
Permanent pasture most economical condition of soil . 194 
Nitrification and rotation of crops 195 



CONTENTS. XV11 

APPENDIX TO CHAPTER IV. 
NOTE 

I. Old theories of nitrification . . . . . .196 

II. Nitrification takes place in solutions devoid of organic 

matter 196 

III. Oxidising power of micro-organisms in soils . . .197 

IV. Effect of urine on nitrification in soils . . . .197 
V. Solution used by Professor Frankland in cultivating nitri- 

ficative micro-organisms . . . . . .198 

VI. Experiments by Boussingault on rate of nitrification . 198 
VII. Nitrogen as nitrates in Rothamsted soils after bare fallow 

in Ib. per acre ........ 198 

CHAPTER V. POSITION OF PHOSPHORIC ACID IN 
AGRICULTURE. 

Occurrence of phosphoric acid in nature 199 

Mineral sources of phosphoric acid ...... 200 

Apatite and phosphorite ........ 200 

Coprolites 201 

Occurrence of phosphoric acid in guanos ..... 202 

Universal occurrence in common rocks ..... 202 

Occurrence in the soil ........ 203 

Condition in which phosphoric acid occurs in the soil* . . 203 

Occurrence in plants ........ 204 

Occurrence in animals 205 

Sources of loss of phosphoric acid in agriculture . . . 205 
Loss of phosphoric acid by drainage . . . . .206 

Artificial sources of loss of phosphoric acid .... 206 

Amount of phosphoric acid removed in milk . . . . 207 

Loss of phosphoric acid in treatment of farmyard manure . 208 

Loss of phosphoric acid in sewage 208 

Sources of artificial gain of phosphoric acid .... 208 

APPENDIX TO CHAPTER V. 

NOTE 

I. Composition of apatite (Voelcker) 210 

II. Percentage of phosphoric acid in the commoner rocks . 211 

CHAPTER VI. POSITION OF POTASH IN AGRICULTURE. 

Potash of less importance than phosphoric acid . . .212 
Occurrence of potash 213 

b 



XV111 CONTENTS. 

Felspar and other potash minerals 213 

Stassfurt salts . . . . . . . . .214 

Occurrence of saltpetre 215 

Occurrence of potash in the soil . . . . . .215 

Potash chiefly in insoluble condition in soils . . . .216 

Percentage of potash in plants and plant-ash . . . .216 

Occurrence of potash in animal tissue . . . . .217 

Sources of loss of potash 217 

Amount of potash removed in crops . . . . .218 

Amount of potash removed in milk . . . . . .218 

Potash manures ....... .218 



APPENDIX TO CHAPTER VI. 
NOTE 

I. Amount of potash in different minerals .... 220 
II. Quantity of potash obtained from 1000 Ib. of different 

kinds of vegetation in the manufacture of potashes . 220 



PART III. MANURES. 

CHAPTER VII. FARMYARD MANURE. 

Variation in its composition ....... 223 

Made up of three classes of constituents ..... 224 

Solid excreta 

Its nature 224 

Difference in composition of the solid excreta of the 
different farm animals ...... 224 

Causes of this difference ...... 225 

Percentage of manurial ingredients in solid excreta of 
different animals . . . . . . .226 

Urine 

Its nature 228 

Variation in its composition 229 

Causes of this variation ....... 229 

Manurial value of the urine of the different farm animals 230 
Percentage of the organic matter, nitrogen, and mineral 
substances in the food, voided in the solid excreta and 

urine 232 

Comparison of manurial value of total excrements of the 
different farm animals ...... 234 



CONTENTS. xix 

Nature of changes undergone by food in process of 

digestion . . . 235 

Litter 

Its uses 236 

Straw as litter, and its qualifications . . . .237 

Composition of different kinds of straw .... 238 

Loam as litter 239 

Peat as litter 240 

Comparison of properties of peat-moss and straw . . 241 
The bracken-fern as litter . . . . . .241 

Dried leaves as litter . . . . . . . 242 

Manures produced by the different animals 
Horse-manure 

Amount produced ........ 243 

Its nature and composition ...... 243 

Amount of straw used for litter ..... 244 

Sources of loss on keeping 245 

How to prevent loss ....... 245 

Use of " fixers," and the nature of their action . . 245 
Coiv-manure 

Amount produced ........ 248 

Its nature and composition ...... 248 

Amount of straw used as litter ..... 248 

Sources of loss on keeping ...... 249 

Advantages of short dung ...... 249 

Pig-manure 

Amount produced ....... 250 

Its nature and composition ...... 250 

Amount of straw used as litter . . . . .251 

Sheep-manure 

Amount produced ....... 251 

Nature and composition ...... 251 

Amount of straw used as litter ..... 252 

Methods of calculating amount of manure produced on the 

farm 252, note 

Fermentation of farmyard manure 

Action of micro-organic life in producing fermentation . 255 
Two classes of bacteria active in this work, aerobics and 

anaerobies ......... 255 

Conditions influencing fermentation 

Temperature 256 

Openness to the air . . . . .256 



XX CONTENTS. 

Dampness . . . . . . . . . 257 

Composition of manure ....... 257 

Products of fermentation ....... 257 

Analyses of farmyard manure 

Dr Voelcker's experiments 259 

Variation in composition - . . . . . . . 259 

Amounts of moisture, organic matter (containing nitrogen), 
and mineral matter . . . . . . .260 

Its inanurial value compared with nitrate of soda, sulphate 
of ammonia, and superphosphate . . . . .260 

Comparison of fresh and rotten manure 

The nature and amount of loss sustained in the process of 

rotting 261 

Ought manure to be applied fresh or rotten ? . . . 262 
Relative merits of covered and uncovered manure-heaps . . 263 
Methods of application of farmyard manure to the field 

Merits and demerits of the different methods . . .265 
Setting it out in heaps . . . . . . .265 

Spreading it broadcast, and letting it lie . . . . 266 

Ploughing it in immediately . . . . . .267 

Value and function of farmyard manure 

As a supplier of the necessary elements of plant-food . 268 
As a " universal " manure . ...... 269 

Proportion in which nitrogen, phosphoric acid, and potash 
are required by crops . . . . . . .269 

Proportion in which they are present in farmyard manure 270 
Farmyard manure poor in nitrogen . . . . .270 

Lawes' and Gilbert's experiments . . . . .271 

How it may be best reinforced by the use of " artificials " . 271 
Indirect value of farmyard manure as a supplier of humus 

to the soil 273 

Its influence on soil-texture ...... 273 

Its influence in setting free inert fertilising matter in the 
soil .......... 274 

Rate at which farmyard manure ought to be applied . . 275 
Lasting nature of farmyard manure ..... 276 

Its economic value . . . . . . . . .276 



APPENDIX TO CHAPTER VII. 
NOTE 

I. Difference in amount of excreta voided for food con- 
sumed ... 279 



CONTENTS. xxi 

NOTE 

II. Solid excreta voided by sheep, oxen, and cows . .279 

III. Urine voided by sheep, oxen, and cows . . . 280 

IV. Percentage of food voided in the solid and liquid ex- 

crements ........ 281 

V. Pig excrements 281 

VI. Manurial constituents in 1000 parts of ordinary foods . 282 
VII. Analyses of stable - manure, made respectively with 

peat-moss litter and wheat-straw .... 283 

VIII. Analyses of bracken ' . 283 

IX. Analyses of horse-manure ...... 283 

X. The nature of the chemical reactions of ammonia 

11 fixers" 284 

XI. Analyses of cow-manure ...... 286 

XII. Composition of 'fresh and rotten farmyard manure . 286 

XIII. Comparison of fresh and rotten manure . . . 288 

XIV. Lord Kinnaird's experiments . . . . .289 
XV. Drainings of manure-heaps ...... 290 

XVI. Amounts of potash and phosphoric acid removed by 

rotation from a Prussian morgen (.631 acre) . . 290 

XVII. Composition of farmyard manure (fresh) . . . 291 

XVIII. The urine (quantity voided) 291 



CHAPTER VIII. GUANO. 

Importance in agriculture ....... 293 

Influence on British farming . . . . . . .294 

Influence of guano not wholly good ...... 295 

Value of guano as a manure ....... 296 

Origin and occurrence of guano ...... 297 

Variation in composition of different guanos .... 299 

I. Nitrogenous guano 

(a) Peruvian guano 300 

Different deposits of Peruvian guano . . . 301 

Appearance, colour, and nature of Peruvian guano . 303 

Composition of Peruvian guano .... 304 

(b) Other nitrogenous manures : Angamos, Ichaboe . 306 
II. Phosphatic guanos 

Occurrence of phosphatic guanos ..... 308 

Inequality in composition of phosphatic guanos . . 309 

" Dissolved " phosphatic guano ..... 310 

" Equalised " or " rectified " guano ..... 311 



XX11 CONTENTS. 

The action of phosphatic guauos as manures . . .312 
Proportion of fertilising constituents in guano . . 314 

Mode of application of guanos . . . . .315 

Quantity of guano to be used ...... 317 

Adulteration of guano . . . . . . .318 

So-called guanos 

Fish-guano 320 

Value of fish-guano 322 

Meat-meal guano ........ 324 

Value of meat-meal guano ...... 324 

Bat guano 325 

Pigeon and fowl dung 325 

APPENDIX TO CHAPTER VIII. 
NOTE 

I. Peruvian guano imported into United Kingdom, 1865- 

1893 327 

II. Guano deposits of the world ...... 327 

III. Composition of concretionary nodules . . . .328 

IV. Table showing gradual deterioration of Peruvian guano, 

1867-1881 329 

V. Composition of different guanos ..... 329 

VI. Liebig's theory as to the action of oxalic acid in guano . 330 

VII. Analyses of dung of fowls, pigeons, ducks, and geese . 331 



CHAPTER IX. NITRATE OF SODA. 

Amount of exports . . . . . . . . .332 

Date of discovery of nitrate deposits ..... 333 

The origin of nitrate deposits . . . . . . .334 

Forbes and Darwin on the theory of their origin . . .335 
Source of nitric acid in nitrate of soda ..... 337 

Guano theory of origin of nitrate of soda ..... 337 

Nitric acid in nitrate of soda probably derived from sea-weed . 339 
Appearance of nitrate-fields .... ... 340 

The method of mining the nitrate of soda . . . .341 

Composition of caliche . . . . . . .342 

Extent of the nitrate deposits ....... 342 

Composition and properties of nitrate of soda . . . .343 

Nitrate applied as a top-dressing . . . . . .344 

Nitrate of soda encourages deep roots ..... 344 



CONTENTS. XX111 

Is nitrate of soda an exhausting manure ? 345 

Crops for which nitrate of soda is suited . . . . .346 

Method of application of nitrate of soda ..... 347 

Importance of having a sufficiency of other fertilising con- 
stituents .......... 348 

Conclusions drawn ......... 349 

APPENDIX TO CHAPTER IX. 

Total shipments from South America, 1830-1893 . . .351 
Total imports into Europe and United Kingdom, 1873-1892 . 351 



CHAPTER X. SULPHATE OF AMMONIA. 

Value of ammonia as a manure ...... 352 

Sources of sulphate of ammonia ...... 353 

Ammonia from gas-works ....... 353 

Other sources .......... 354 

Composition, &c., of sulphate of ammonia .... 355 

Application of sulphate of ammonia . . . . .356 

APPENDIX TO CHAPTER X. 

Production of sulphate of ammonia in United Kingdom, 

1870-1892 358 



CHAPTER XI. BONES. 

Early use of bones ......... 359 

Different forms in which bones are used ..... 360 

Composition of bones ........ 362 

The organic matter of bones . . . . . . .363 

The inorganic matter of bones ....... 363 

Treatment of bones ......... 364 

Action of bones ......... 365 

Dissolved bones ......... 368 

Crops suited for bones ........ 368 

Bone-ash 369 

Bone-char or bone-black ........ 369 



XXIV CONTENTS. 

APPENDIX TO CHAPTER XI. 
NOTE 

I. Analysis of bone-meal 371 

II. Analysis of dissolved bones 371 

III. Composition of bone-ash ....... 372 

IV. Composition of bone-char 372 



CHAPTER XII. MINERAL PHOSPHATES. 
Coprolites .......... 373 

Canadian apatite or phosphorite . . . . . .374 

Estremadura or Spanish phosphates 375 

Norwegian apatite . . . . . . . . .376 

Charlestown or South Carolina phosphate . . . .376 

Belgian phosphate ......... 377 

Somnie phosphate . . . . . . . . .378 

Florida phosphate 378 

Lahn phosphate . . . . . . . . .379 

Bordeaux or French phosphate ...... 379 

Algerian phosphate . . . . . . . . .379 

Crust guanos .......... 379 

Value of mineral phosphates as manures 380 

APPENDIX TO CHAPTER XII. 

Imports of phosphates . . . . . . . .381 



CHAPTER XIII. SUPERPHOSPHATES. 

Discovery of superphosphate by Liebig ..... 382 

Manufacture of superphosphate 383 

Nature of the reaction taking place ...... 385 

Phosphates of lime ......... 385 

Reverted phosphate . . . . . . . .389 

Value of reverted phosphate . . . . . . .391 

Composition of superphosphates ...... 391 

Action of superphosphates . . . . . . .392 

Action of superphosphate sometimes unfavourable . . . 395 
Application of superphosphate . . . . . . .395 

Value of insoluble phosphates ....... 396 

Rate at which superphosphate is applied 397 



CONTENTS. XXV 



APPENDIX TO CHAPTER XIII. 
NOTE 

I. The formulae, and molecular and percentage composition, 

of the different phosphates ...... 398 

II. Reactions of sulphuric acid and phosphate of lime . . 398 

III. Table for conversion of soluble phosphate into insoluble 

phosphate 399 

IV. Action of iron and alumina in causing reversion . . 399 
V. Relative trade values of phosphoric acid in different 

manures ......... 400 



CHAPTER XIV. THOMAS-PHOSPHATE OR 
BASIC SLAG. 

Its manufacture ......... 401 

Not at first used 403 

Discovery of its value as a manure 403 

Composition of basic slag ....... 404 

Processes for preparing slag ....... 406 

Solubility of basic slag . . . . . . . .408 

Darmstadt experiments with basic slag . . . . . 410 

Results of other experiments . . . . . . .413 

Soils most suited for slag . . . . . . .414 

Rate of application . . . . . . . . .414 

Method of application . . . . . . . .416 

APPENDIX TO CHAPTER XIV. 

Analysis of basic slag . . . . . . . .417 



CHAPTER XV. POTASSIC MANURES. 

Relative importance . . . . . . . .418 

Scottish soils supplied with potash . . . . . .419 

Sources of potassic manures . . . . . . .419 

Stassfurt potash salts . . . . . . . .420 

Relative merits of sulphate and muriate of potash . . .421 
Application of potash manures ....... 422 

Soils and crops suited for potash manures .... 423 

Rate of application ......... 423 



XXVI CONTENTS. 



CHAPTER XVI. MINOR ARTIFICIAL MANURES. 

Scutch 427 

Shoddy and wool-waste ........ 427 

Soot 428 



CHAPTER XVII. SEWAGE AS A MANURE. 

Irrigation .......... 431 

Effects of continued application of sewage .... 433 

Intermittent irrigation . . . . . . . .434 

Crops suited for sewage . . . . . . . .434 

Treatment of sewage by precipitation, &c. .... 436 

Value of sewage sludge ........ 439 



CHAPTER XVIII. LIQUID MANURE .... 442 



CHAPTER XIX. COMPOSTS. 

Farmyard manure a typical compost . . . . .446 
Other composts ......... 447 



CHAPTER XX. INDIRECT MANURES. 

Lime 449 

Antiquity of lime as a manure . . . . . .449 

Action of lime ......... 449 

Lime a necessary plant-food ...... 450 

Lime of abundant occurrence ...... 452 

Lime returned to the soil in ordinary agricultural practice 452 

Different forms of lime 453 

Caustic lime ......... 453 

Lime acts both mechanically and chemically . . .455 
I. Mechanical functions of lime ...... 455 

Action on soil's texture ....... 455 

Lime renders light soils more cohesive . . . .457 

II. Chemical action of lime ....... 457 



CONTENTS. XXV11 

III. Biological action of lime . ' . . . . . .459 

Action of lime on nitrogenous organic matter . .460 
Recapitulation . . . . . . . . .461 

CHAPTER XXL INDIRECT MANURES GYPSUM, 
SALT, ETC. 

Gypsum ........... 462 

Mode in which gypsum acts . . . . . .462 

Salt 465 

Antiquity of the use of salt . . . . . . 465 

Nature of its action ........ 465 

Salt not a necessary plant-food . . . . . .466 

Can soda replace potash ? . . . . . . .466 

Salt of universal occurrence . . . . . .467 

Special sources of salt . . . . . . .468 

The action of salt 468 

Mechanical action on soils . . . . . . .470 

Solvent action . . . . . . . . .470 

Best used in small quantities along with manures . .472 
Affects quality of crop . . . . . . .472 

Rate of application 473 



CHAPTER XXII. THE APPLICATION OF MANURES. 

Influence of manures in increasing soil-fertility . . .474 
Influence of farmyard manure on the soil . . . .475 

Farmyard manure v. artificials ....... 476 

Farmyard manure not favourable to certain crops . . . 477 
Conditions determining the application of artificial manures . 477 

Nature of the manure . . . . . . .478 

Nitrogenous manures . . . . . . . .478 

Phosphatic manures . . . . . . . .480 

Potash manures ......... 480 

Nature of soil .......... 481 

Nature of previous manuring . . . ... . . 482 

Nature of the crop ......... 483 

Amounts of fertilising ingredients removed from the soil by 
different crops ......... 484 

Capacity of crops for assimilating manures .... 486 

Difference in root-systems of different crops . . . 488 



XXviii CONTENTS. 

Period of growth 489 

Variation in composition of crops . . . . .490 

Absorption of plant-food ....... 490 

Fertilising ingredients lodge in the seed .... 491 

Forms in which nitrogen exists in plants 491 

Bearing of above on agricultural practice .... 492 

Influence of excessive manuring of crops . . . . .492 



CHAPTER XXIII. MANURING OF THE COMMON 
FARM CROPS. 

Cereals ........... 493 

Especially benefited by nitrogenous manures . . . 494 
Power of absorbing silicates . . . . . .494 

Barley 495 

Period of growth ....... 495 

Most suitable soil ....... 496 

Farmyard manure not suitable 497 

Importance of uniform manuring of barley . . 497 

Norfolk experiments on barley 497 

Proportion of grain to straw . . . . .498 

Wheat 499 

Rothamsted experiments ....... 500 

Continuous growth ....... 500 

Flitcham experiments . . . . . . .500 

Oats 501 

A very hardy crop ....... 502 

Require mixed nitrogenous manuring . . . .502 

Arendt's experiments 503 

Aveniue ......... 503 

Quantities of manures ...... 504 

Grass 504 

Effect of manures on herbage of pastures . . . .505 

Influence of farmyard manure . . . . . .506 

Influence of soil and season on pastures .... 507 

Manuring of meadow land ...... 508 

Baiigor experiments . . . . . . .508 

Norfolk experiments . . . . . . 509 

Manuring of permanent pastures ..... 509 

Roots .510 

Influence of manure on composition . . . .512 
Nitrogenous manures increase sugar 512 



CONTENTS. xxix 

Amount of nitrogen recovered in increase of crop . .513 

Norfolk experiments 513 

Manure for swedes . . . . . . .514 

Highland Society's experiments 515 

Manuring for rich crops of turnips . . . .516 
Experiments by the author on turnips . . . .516 

Potatoes 517 

Highland Society's experiments . . . . .518 

The Rothamsted experiments . . . . . .519 

Effect of farmyard manure ..... 520 

Manuring of potatoes in Jersey 521 

The influence of manure on the composition . . 521 
Leguminous crops ......... 522 

Leguminous plants benefit by potash .... 523 

Nitrogenous manures may be hurtful .... 523 

Clover sickness ........ 524 

Alternate wheat and bean rotation ..... 524 

Beans . . .525 

Manure for beans ....... 525 

Relative value of manurial ingredients . . ' . 526 
Gypsum as a bean manure ...... 526 

Effect of manure on composition of crop . . . 527 

Peas 527 

Hops 528 

Cabbages 528 

APPENDIX TO CHAPTER XXIII. 

Experiments on bean-manuring . . . . . 530 



CHAPTER XXIV. ON THE METHOD OF APPLICATION, 
AND ON THE MIXING OF MANURES." 

Equal distribution of manures ....... 531 

Mixing manures ......... 532 

Risks of loss in mixtures ........ 533 

Loss of ammonia ........ 533 

Effects of lime on ammonia . . . . . .535 

Loss of nitric acid ........ 536 

Reversion of phosphates . . . . . . .537 

Manurial ingredients should be applied separately . . . 538 



XXX CONTENTS. 



CHAPTER XXV. ON THE VALUATION AND ANALYSIS 
OF MANURES. 

Value of chemical analysis ....... 539 

Interpretation of chemical analysis . . . . . .539 

Nitrogen . . . . . . . . . . 540 

Phosphoric acid ......... 541 

Importance of mechanical condition of phosphate . . 542 

Potash 542 

Other items in the chemical analysis of manures . . . 543 

Fertilisers and Feeding Stuffs Act ...... 543 

Different methods of valuing manures . . . . . 544 

Unit value of manurial ingredients ...... 544 

Intrinsic value of manures ....... 545 

Field experiments 545 

Educational value of field experiments ..... 547 

Value of manures deduced from experiments .... 548 

Value of unexhausted manures ...... 549 

Potential fertility of a soil 549 

Tables of value of unexhausted manures ..... 551 

APPENDIX TO CHAPTER XXV. 
NOTE 

I. Factors for calculating compounds from manurial in- 
gredients . . . . . . . . . 553 

II. Units for determining commercial value of manures and 

cash prices of manures 554, 555 

III. Manurial value of nitrogen and potash in different sub- 

stances .......... 556 

IV. Comparative manurial value of different forms of nitrogen 

and potash ......... 557 

V. Lawes' and Gilbert's tables for calculating unexhausted 

value of manures ........ 559 



CHAPTER XXVI. THE ROTHAMSTED EXPERIMENTS. 

Nature of experiments on crops and manures . . . .561 
Soil of Rothamsted 561 

Table I. List of Rothamsted field experiments . . .562 

Wheat experiments 

Unmanured plots 562 



CONTENTS. XXXI 

Wheat grown continuously on same land (unmanured) . 562 
Table II. Results of first eight years . . .562 
ii III. Results of subsequent forty years . . 562 
Table IV. Wheat grown continuously with farmyard man- 
ure (14 tons per annum) .... 564 
ii V. Wheat grown continuously with artificial man- 
ures 565 

Table VI. Experiments on the growth of barley, forty years, 

1852-91 566 

it VII. Experiments on the growth of oats, 1869-78 . 567 

ii VIII. Experiments on root crops Swedish turnips 568, 569 
ii IX. Experiments on mangel-wurzel . . . 568, 569 
.. X. Experiments with different manures on permanent 

meadow-land, thirty-six years, 1856-91 . . 570 
.1 XI. Experiments on the growth of potatoes average 

for five seasons, 1876-80 571 

u XII. Experiments on growth of potatoes (continued) 

average for twelve seasons, 1881-92 . . . 572 



INDEX 573 



PAET I. 
HISTORICAL INTRODUCTION 



MANUKES AND THE PEINCIPLES 
OF MANUEING. 



HISTOEICAL INTBODUCTIOJST. 

AGRICULTURAL CHEMISTRY, like most branches of nat- 
ural science, may be said to be entirely of modern 
growth. While it is true we have many old specu- 
lations on the subject, they can scarcely be said to 
possess much scientific value. The great questions 
which had first to be solved by the agricultural 
chemist were, What is the food of plants ? and, 
What is the source of that food ? The second of 
these two questions more easily admitted of answer 
than the first. The source of plant-food could only 
be the atmosphere or the soil. As the composition 
of the atmosphere, however, was not discovered till 
the close of last century, and the chemistry of the 
soil is a question which is still requiring much work 



4 HISTORICAL INTRODUCTION. 

ere we shall be in possession of anything like a full 
knowledge of it, it will be at once obvious that the 
very fundamental conditions for a solution of the 
question were awanting. The beginning, then, of a 
true scientific agricultural chemistry may be said to 
date from the brilliant discoveries associated with 
the names of Priestley, Scheele, Lavoisier, Cavendish, 

and Black that is, towards the close of last century. 

* 

Early Theories on Source of Plant-food. 

While this is so, and while we must regard the 
early attempts made towards solving this question as 
being, for the most part, of little scientific value, it 
is not without interest, from the historical point of 
view, to glance briefly at some of these old interesting 
speculations. 

The Aristotelian doctrine, regarding the possibility 
of dividing matter into the so-called four primary 
elements, /ire, air, earth, and water, which obtained 
in one form or another till the birth of modern 
chemistry, had naturally an important influence on 
these early theories. 

Van Helmont s Theory. 

Among the earliest and most important attempts 
made to solve the problem of plant-growth was that 
by Jean Baptiste Van Helmont, one of the best known 
of the alchemists, who flourished about the beginning 
of the seventeenth century. Van Helmont believed 






VAN HELMONT'S THEOKY. 5 

that he had proved by a conclusive experiment that 
all the products of vegetables were capable of being 
generated from water. The details of this classical 
experiment were as follows : 

" He took a given weight of dry soil 200 Ib. and 
into this soil he planted a willow-tree that weighed 
5 Ib., and he watered this carefully from time to time 
with pure rain-water, taking care to prevent any dust 
or dirt falling on to the earth in which the plant 
grew. He allowed this to go on growing for five 
years, and at the end of that period, thinking his 
experiment had been conducted sufficiently long, he 
pulled up his tree by the roots, shook all the earth 
off, dried the earth again, weighed the earth and 
weighed the plant. He found that the plant now 
weighed 169 Ib. 3 ounces, whereas the weight of the 
soil remained very nearly what it was about 200 Ib. 
It had only lost 2 ounces in weight." l 

The conclusion, therefore, come to by Van Helmont 
was that the source of plant-food was water. 2 

1 The History of the Chemical Elements. By Sir Henry E. Ros- 
coe, F.K.S. (Wm. Collins, Sons, & Co.) 

2 Van Helmont's science was, however, of an extremely rudimentary 
nature, as may be evidenced by the belief he entertained that the 
smells which arise from the bottom of morasses produce frogs, slugs, 
leeches, and other things ; as well as by the following recipe which 
he gave for the production of a pot of mice: " Press a dirty shirt 
into the orifice of a vessel containing a little corn, after about twenty- 
one days the ferment proceeding from the dirty shirt, modified by the 
odour of the corn, effects a transmutation of the wheat into mice." 
The crowning point ill this recipe, however, lay in the fact that he 



6 HISTORICAL INTRODUCTION. 

Diybys Theory. 

Some fifty years later an extremely interesting book 
was published bearing the following title : ' A Dis- 
course concerning the Vegetation of Plants, spoken 
by Sir Kenelm Digby, at Gresham College, on the 
23d of January 1660. (At a meeting of the Society 
for promoting Philosophical Knowledge by Experi- 
ments. London : Printed for John Williams, in Little 
Britain, over against St Botolph's Church, 1669.) ' 
The author attributes plant-growth to the influence 
of a lalsam which the air contains. This book is 
especially interesting as containing the earliest rec- 
ognition of the value of saltpetre as a manure. The 
following is an extract from this interesting old 
work : 

" The sickness, and at last the death of a plant, 
in its natural course, proceeds from the want of that 
balsam ick saline juice ; which, I have said, mak'es it 
swell, germinate, and augment itself. This want may 
proceed either from a destitution of it in the place 
where the plant grows, as when it is in a barren soil 
or bad air, or from a defect in the plant itself, that 
hath not vigour sufficient to attract it, though it be 
within the sphere of it ; as when the root has become 

asserted that he had himself witnessed the fact, and, as -an interest- 
ing and corroborative detail, he added that the mice were born full- 
grown. See 'Louis Pasteur: His Life and Labours.' By his Son- 
in-law. Translated by Lady Claud Hamilton. (Longmans, Green, 
& Co.) P. 89. 



DIGBY'S THEORY. 7 

so hard, obstructed and cold, as that it hath lost its 
vegetable functions. Now, both these may be renie- 
dy'd, in a great measure, by one and the same physick. 
. . . The watering of soils with cold hungray springs 
doth little good ; whereas muddy saline waters brought 
to overflow a piece of ground enrich it much. But 
above all, well-digested dew makes all plants luxuriate 
and prosper most. Now what may it be that endues 
these liquors with such prolifick virtue ? The meer 
water which is common to them all, cannot be it; 
there must be something else enclosed within it, to 
which the water serves but for a vehicle. Examine 
it by spagyric art, and you will find that it is nothing 
else than a nitrous salt, which is dilated in the water. 
It is this salt which gives foecundity to all things : 
and from this salt (rightly understood) not only all 
vegetables, but also all minerals draw their origine. 
By the help of plain salt-peter, dilated in water and 
mingled with some other fit earthy substance, that 
may familiarize it a little with the corn into which 
I endeavoured to introduce it, I have made the bar- 
renest ground far out-go the richest, in giving a pro- 
digiously plentiful harvest. I have seen hemp-seed 
soaked in this liquor, that hath in due time made 
such plants arise, as, for the tallness and hardness 
of them, seemed rather to be coppice-wood of fourteen 
years' growth at least, than plain hemp. The fathers 
of the Christian doctrine at Paris still keep by them 
for a monument (and indeed it is an admirable one) 



8 HISTORICAL INTRODUCTION. 

a plant of barley consisting of 249 stalks, springing 
from one root or grain of barley ; in which they 
counted above 18,000 grains or seeds of barley. But 
do you think that it is barely the salt-peter, imbibed 
into the seed or root, which causeth this fertility ? 
no : that would be soon exhausted and could not 
furnish matter to so vast a progeny. The salt-peter 
there is like a magnet, which attracts a like salt 
which fecundates the air, and gave cause to the 
Cosmopolite to say there is in the air a hidden food 
of life." 1 

DuJiamel and Hales. 

The names of the French writer, Duhamel, and of the 
English, Stephen Hales, may be mentioned in passing 
as authors of works bearing on the question of veg- 
etable physiology. Both of these writers flourished 
about the middle of the eighteenth century. The 
writings of the former contained much valuable in- 
formation on the effects of grafting, motion of sap, and 
influence of light on vegetable growth, and also the 
results of experiments which the author had carried 
out on the influence of treating plants with certain 
substances. ' Statical Essays, containing Vegetable 
Staticks ; or an Account of some Statical Experiments 
on the Sap of Vegetables, by Stephen Hales, D.D.' (2 

1 He then goes on to relate a number of experiments by Cornelius 
Drebel and Albertus Magnus, showing the refreshing power of this 
balsam, and then those of Quercitan with roses and other flowers, 
and his own with nettles. 



JETHKO TULLS THSOBY. 9 

vols.), was published in London in 1738 ; and contain- 
ed, as will be seen from its title, records of experiments 
of very much the same nature as those of Duhamel. 

Jethro TulVs Theory. 

Some reference may be made to a theory which 
created a considerable amount of interest when it was 
first published viz., that of Jethro Tull. The chief 
value of Tull's contribution to the subject of agricul- 
tural science was, that he emphasised the importance 
of tillage operations by putting forward a theory to 
account for the fact, universally recognised, that the 
more thoroughly a soil was tilled, the more luxuriant 
the crops would be. As Tull's theory had a very 
considerable influence in stirring up interest in many 
of the most important problems in agricultural chem- 
istry, and as it contained in itself much, the value of 
which we have only of late years come to understand, 
a brief statement of this theory may not be without 
interest. 

According to Tull the food of plants consists of the 
particles of the soil. These particles, however, must 
be rendered very minute before they become available 
for the plant, which absorbs them by means of its root- 
lets. This pulverisation of the soil goes on in nature 
independently of the farmer, but only very slowly, and 
the farmer has therefore to hasten it on by means of 
tillage operations. The more efficiently these opera- 
tions are carried on, the more abundant will the supply 



10 HISTORICAL INTRODUCTION. 

of plant -food be rendered in the soil. He conse- 
quently introduced and advocated the system of horse- 
hoe husbandry. This theory, he informs us, was sug- 
gested to him by the custom, which he had noticed on 
the Continent, of growing vines in rows, and hoeing the 
intervals between these rows from time to time. The 
excellent results which followed this mode of cultiva- 
tion induced him to adopt it in England for his farm 
crops. He accordingly sowed his crops in rows or 
ridges, wide enough apart to admit of thorough tillage 
of the intervals by ploughing as well as by hand- 
hoeing. This he continued until the plant had reached 
maturity. As to the exact width of the interval most 
suitable, he made a large number of experiments. At 
first, in the cultivation of wheat, he made this interval 
six feet wide; but latterly he adopted an interval 
of lesser width, that finally arrived at being between 
four and five feet. He likewise experimented on each 
separate ridge as to which was the best number of 
rows of wheat to be sown, latterly adopting, as 
most convenient, two rows at ten inches apart. The 
great success which he met with in this system of 
cultivation induced him to publish the results of 
his experiments in his famous work, ' Horse-Hoeing 
Husbandry/ 

While Tull's theory was based on principles at 
heart thoroughly sound, he was carried away by his 
personal success into drawing unwarrantable deduc- 
tions. Thus he came to the conclusion that rotation 



DISCOVERY OF THE SOURCE OF PLANTS' CARBON. 11 

of crops was unnecessary, provided that a thorough 
system of tillage was carried out. Manures also, ac- 
cording to him, might be entirely dispensed with 
under his system of cultivation, for the true function 
of all manures is to aid in the pulverisation of the 
soil by fermentation. 

The first really valuable scientific facts contributed 
to the science were made by Priestley, Bonnet, Ingen- 
housz, and Senebier. 

Discovery of the Source of Plants Carbon. 

To Charles Bonnet (1720-1793), a Swiss naturalist, 
is due the credit of having made the first contribu- 
tion to a discovery of very great importance viz., 
the true source of the carbon, which we now know 
forms so large a portion of the plant - substance. 
Bonnet, who had devoted himself to the question of 
the function of leaves, noticed that when these were 
immersed in water bubbles were seen, after a time, 
to collect on their surface. De la Hire, it ought 
to be pointed out, had noticed this same fact about 
sixty years earlier. It was left to Priestley, how- 
ever, to identify these bubbles with the gas he had 
a short time previously discovered viz., oxygen. 
Priestley had observed, about this time, the interest- 
ing fact that plants possessed the power of purify- 
ing air vitiated by the presence of animal life. 1 The 

1 Priestley, however, did riot realise that carbonic acid gas was a 
necessary plant-food ; on the contrary, he considered it to have a 



12 HISTOKICAL INTRODUCTION. 

next step in this highly interesting and important 
discovery was taken by John Ingenhousz (1730-1799), 
an eminent physician and natural philosopher. In 
1779, Ingenhousz published a work in London entitled 
* Experiments on Vegetables.' In it he gives the 
results of some important experiments he had made 
on the question already investigated by Bonnet and 
Priestley. These experiments proved that plant- 
leaves only gave up their oxygen in the presence of 
sunlight. In 1782 he published another work on 
'The Influence of the Vegetable Kingdom on the 
Animal Creation/ l 

The source of the gas, which Bonnet had first 
noticed to be given off from plant-leaves, Priestley had 
identified as oxygen, and Ingenhousz had proved to be 
only given off under the influence of the sun's rays, 
was finally shown by a Swiss naturalist, Jean Senebier 2 
(1742-1809), to be the carbonic acid gas in the air, 
which the plant absorbed and decomposed, giving out 
the oxygen and assimilating the carbon. 

deleterious action on plant -growth. Percival was really the first to 
point out that carbonic acid gas was a plant-food. 

1 It is recorded as an instance of the scientific enthusiasm of the 
man, that he was wont to carry about with him bottles containing 
oxygen, which he had obtained from cabbage-leaves, as also coils of 
iron wire, with which he could illustrate the brilliant combustion 
which ensued on burning the latter in oxygen gas. 

2 For a full account of Senebier's researches, see l Physiologic 
vegetale, contenant une description des organes des plantes, et une 
exposition des pheuomenes produits par leur organisation, par Jean 
Senebier.' (5 tomes. Geneve, 1800.) 



TREATISE ON AGRICULTURAL CHEMISTRY. 13 

Publication of First English Treatise on Agricultural 
Chemistry. 

In 1795, a book dealing with the relations between 
chemistry and agriculture was published. This work 
was written by a Scottish nobleman, the Earl of 
Dundonald, and possesses especial interest from the 
fact that it is the first book in the English language 
on agricultural chemistry. The full title is as follows : 
* A Treatise showing the Intimate Connection that 
subsists between Agriculture and Chemistry/ 

In his introduction the author says : " The slow 
progress which agriculture has hitherto made as a 
science is to be ascribed to a want of education on 
the part of the cultivators of the soil, and to a want 
of knowledge, in such authors as have written on 
agriculture, of the intimate connection that subsists 
between the science and that of chemistry. Indeed, 
there is no operation or process not merely mechanical 
that does not depend on chemistry, which is defined 
to be a knowledge of the properties of bodies, and of 
the effects resulting from their different combinations." 

In quoting this passage Professor S. W. Johnson 
remarks : l " Earl Dundonald could not fail to see that 
chemistry was ere long to open a splendid future for 
the ancient art that had always been and always will 
be the prime supporter of the nations. But when he 

1 How Crops Grow. By Professor S. W. Johnson. Macmillan & 
Co. (Introduction, p. 4.) 



14 HISTORICAL INTRODUCTION. 

wrote, how feeble was the light that chemistry could 
throw upon the fundamental questions of agricultural 
science ! The chemical nature of the atmosphere was 
then a discovery of barely twenty years' standing. 
The composition of water had been known but twelve 
years. The only account of the composition of plants 
that Earl Dundonald could give was the following: 
' Vegetables consist of mucilaginous matter, resinous 
matter, matter analogous to that of animals, and some 
proportion of oil. . . . Besides these, vegetables con- 
tain earthy matters, formerly held in solution in the 
newly-taken-in juices of the growing vegetables.' To 
be sure, he explains by mentioning in subsequent 
pages that starch belongs to the mucilaginous matter, 
and that on analysis by fire vegetables yield soluble 
alkaline salts and insoluble phosphate of lime. But 
these salts, he held, were formed in the process of 
burning, their lime excepted; and the fact of their 
being taken from the soil and constituting the indis- 
pensable food of plants, his lordship was unacquainted 
with. The gist of agricultural chemistry with him 
was, that plants ' are composed of gases with a small 
proportion of calcareous matter ; for although this dis- 
covery may appear to be of small moment to the prac- 
tical farmer, yet it is well deserving of his attention 
and notice.' " 

De Saussure. 

The year 1804 witnessed the publication of by far 
the most important contribution made to the science 



SOURCE OF PLANT-NITROGEN. - 15 

up till this time. This was ' Eecherches Chimique sur 
la Vegetation/ by Theodore de Saussure, one of the 
most illustrious agricultural chemists of the century. 
De Saussure was the first to draw attention to the 
mineral or ash constituents of the plant; and thus 
anticipate, to a certain extent, the subsequent famous 
" mineral " theory of the great Liebig. The French 
chemist maintained that these ash ingredients were 
essential; and that without them plant-life was im- 
possible. He also adduced fresh experiments of his 
own in support of the theory, based on the experi- 
ments of Bonnet, Priestley, Ingenhousz, and Senebier, 
that plants obtain their carbon from the carbonic 
acid gas in the air, under the influence of the sunlight. 
He was of opinion that the hydrogen and oxygen of 
the plant were, probably, chiefly derived from water. 
He showed that by far the largest portion of the 
plant's substance was derived from the air and from 
water, and that the ash portion was alone derived from 
the soil. To Saussure we owe the first definite state- 
ment on the different sources of the plant's food. It 
may be said that the lapse of nearly a century has 
shown his views to be, in the main, correct. 

Source of Plant-nitrogen. 

There was one question, which, even at that remote 
period in the history of the subject, engaged the atten- 
tion of agricultural chemists viz., the question of the 
source of the plant's nitrogen a question which may 



16 HISTORICAL INTRODUCTION. 

be fitly described at the present hour as still the burn- 
ing question of agricultural chemistry. 1 

As soon as it was discovered that nitrogen was a 
constituent of the plant's substance, speculations as to 
its source were indulged in. The fact that the air 
furnished an unlimited storehouse of this valuable 
element, and the analogy of the absorption of carbon 
(from the same source by plant-leaves), naturally sug- 
gested to the minds of early inquirers that the free 
nitrogen of the air was the source of the plant's 
nitrogen. As, however, no direct experiments could 
be adduced to prove this theory, and as, moreover, 
nitrogen was found in the soil, and seemed to be a 
necessary ingredient of all fertile soils, the opinion 
that the soil was the only source gradually supplanted 
the older theory. Little value, however, must be 
attached to these early theories, as they can scarcely 
be said to have been based on experiments of serious 
value. Indeed it may be safely affirmed, in the light 
of subsequent experiments, that it was impossible for 
this question to be decided at this early period, from 
the fact that analytical apparatus, of a sufficiently 
delicate nature, was then wholly unknown. Indeed 
it is only within the last few years that it has been 
possible to carry out experiments which may be re- 
garded as at all crucial. A short sketch of the 
development of our knowledge of the relation of 
nitrogen to the plant will be given further on. 
1 See p. 40 to 45. 



&' 



INDEX. 



577 






Cress, experiments with, 41. 

Crimea, bones from, 360. 

Cropped soils, nitrates in, 157 lost 
by drainage in, 141. 

Crops, capacity of, for assimilating 
manures, 486 ; difference in root- 
sy stems of, 488 ; manuring of com- 
mon farm, 493 - 530 ; period of 
growth of, 489 ; potash removed 
in, 218 ; suited for sewage, 434 ; 
variation in composition of, 490. 

Crusius on phosphoric acid removed 
from the farm, 207. 

Crust guanos, 308, 379. 

Crystalloids, 491. 

Cura?ao phosphates, 308, 330, 379. 

Darmstadt experiments with basic 
slag, 410-413. 

Darwin on origin of nitrate-fields, 335. 

Daubeny on mineral sources of phos- 
phoric acid, 200. 

Davy, Sir Humphry, lectures of, on 
agricultural chemistry, 17-19 ; on 
heat and water absorbing and re- 
taining properties of soils, 57 ; on 
hygroscopic power of soils, 99. 

Deherain, on nitrification, 52 ; on 
nitrification in sulphate of am- 
monia, 191 ; on rate of nitrification. 
186. 

Denitrification, 177 ; conditions fav- 
ourable for, 178 ; effected by bac- 
teria, 178. 

Derby, Lord, introduction of Peruvian 
guano by, 301. 

Detmer on humus in soil, 47. 

Dew, action of, on guano, 300 ; ex- 
planation of, 77 ; most abundant 
in summer, 78. 

Dicalcic phosphate, 387 ; formula of, 
398; molecular composition of, 
398 ; percentage composition of, 
398. 

Digby, Sir Kenelm, on value of 
nitrates to plants, 45 ; theory of, 
on plant-food, 6-8. 

Diorite, phosphoric acid in, 202, 211. 

Direct manures, 113. 

Dissolved-bone compound, 372. 

Dissolved bones, 368; composition 
of, 371. 

Dissolved guano, 310. 

Dolerite, phosphoric acid in, 202, 211 . 



Dolomite, phosphoric acid in, 202, 
211. 

Downton experiments on sewage- 
sludge, 439. 

Drainage, average of thirteen years, 
160 ; nitrates in, 160 ; nitrates lost 
by, 140 ; phosphoric acid lost by, 
206 ; potash lost by, 217. 

Drainings of manure-heaps, analysis 
of, 290. 

Dried blood, 424 ; composition of, 
424 ; manure for sugar-cane, 425 ; 
potash in, 219 ; rate of nitrification 
in, 192 ; source of nitrogen, 152 ; 
suited for horticulture, 425. 

Dried flesh, 425 ; nitrogen in, 425. 

Dried leaves, as litter, 242 ; compo- 
sition of, 242 ; nitrogen in, 242 ; 
phosphoric acid in, 242 ; potash in, 
242. 

Ducks' dung, analysis of, 331. 

Duhamel and Hales, theory of, on 
plant-growth, 8. 

Dundonald, Earl, treatise by, on agri- 
cultural chemistry, 13. 

Dung and urine, composition of, 
234. 

Dutrochet on absorption of plant - 
food, 55. 

Dyer, Dr Bernard, analyses of stable 
manure by, 283 ; experiments on 
peat as litter, 240 ; on nitrate of 
soda as manure for mangolds, 349. 

Earth, an adulterant of guano, 319 ; 
composition of solid crust of, 102. 

Ecuador, guano deposits at, 327. 

Egyptian guano, nitrogen in, 329; 
phosphoric acid in, 329. 

Elbe, waters of, phosphoric acid in, 
206 ; potash in, 217. 

Elm-tree, water transpired by, 71. 

Enderbury Island guano, 309, 328; 
phosphoric acid in, 328. 

Endosmosis, 55. 

English farming, 86. 

Equalised guano, 311. 

Essex, coprolites from, 374. 

Estremadura phosphate, 375. 

Ethylamine, nitrification in, 182. 

Evaporation from soil, 71, 72, 98. 

Excreta, amount of nitrogen in, 149, 
292 ; composition of, 226, 292 ; dif- 
ference in amount of, for food con- 



2 



578 



INDEX. 



sumed, 279 ; liquid, in farmyard 
manure, 224 ; solid, in farmyard 
manure, 224 ; solid, undigested 
food in, 224 ; solid, voided by cows, 
280, 292 ; solid, voided by horse, 
292 ; solid, voided by oxen, 280 ; 
solid, voided by sheep, 280, 292. 

Factors for calculating manurial in- 
gredients into their different com- 
pounds, 553. 

Falkland guano, 308 ; nitrogen in, 
330 ; phosphoric acid in, 330. 

Fallow-fields, nitrates formed in, 188. 

Fanning Island guano, 328 ; phos- 
phoric acid in, 330. 

Farmyard manure, 223-292 ; action 
of, on soils, 273 ; ammonia in, 258 ; 
amount produced on farm per year, 
252 ; analyses of, 259, 286 ; appli- 
cation of, 264 ; ash of, 287, 288 ; 
carbonic acid gas in, 258 ; classes 
of constituents of, 224 ; compared 
with artificials, 476; composition 
of, 259 ; denitrification in, 179 ; 
depth to plough to, 267 ; effect of, 
on potatoes, 520 ; fertilising matter 
in, 270 ; fire-fang in, 264 ; fresh, 
composition of, 286, 288 ; functions 
of, 268 ; heat in fermentation of, 
78, 253 ; humates in, 259 ; hurnic 
acid in, 258 ; inadequate source of 
nitrogen to soil, 271 ; indirect in- 
fluence of, 273 ; influence of, on 
soil, 475 ; Lawes, Sir J ohn, on 
composition of, 291 ; Lord Kin- 
naird's experiments with, 289 ; 
marsh-gas in, 258 ; mineral matter 
in, 260 ; moisture in, 260 ; nitric 
acid in, 259 ; nitrogen in, 260 ; 
ratio of, to ash ingredients, 271 ; 
organic matter in, 260 ; phosphor - 
etted hydrogen in, 258 ; phosphoric 
acid in, 260 ; potash in, 260 ; pro- 
ducts of decomposition of, 257 ; 
rate of application of, 275 ; re- 
trogression of nitrogen in, 142 ; 
rotten, composition of, 287, 288 
value of, 261 ; rotting, effects of, on, 
262 ; solid excreta in, 224 ; sul- 
phuretted hydrogen in, 258 ; sup- 
plemented with nitrogen, 271 ; 
supplemented with phosphoric acid, 
272 ; temperature, effect of, on soil, 



79, 274 ; typical compost, 446 ; 
ulmates in, 259 ; ulmic acid in, 
258 ; unfavourable to certain crops, 
477 ; urine in, 228 ; value of, 268 ; 
variation in composition of, 223 ; 
water in, 258. 

Fatty acids in guano, 305. 

Felspars, 103 ; albite, 103 ; composi 
tion of, 103 ; labradorite, 220 ; 
oligoclase, 103, 214, 220; ortho- 
clase, 103, 214, 220; phosphoric 
acid in, 211 ; potash manures, 213; 
potash in, percentage of, 213, 220. 

Ferment, aerobic, 173, 255 ; anaerobic, 
255. 

Fermentation, ammonium carbonate 
formed during, 245 ; in bones, 
365 ; heat of, 79 ; of farmyard 
manure, 253 ; of guano, 299 ; tem- 
perature of, 256. 

Fern, bracken, as litter, 241. 

Ferric chloride, test for sulphocyan- 
ates, 355. 

Fertilisers and Feeding Stuffs Act, 543. 

Fertilising ingredients, amount of 
soluble, in soil, 90 ; amounts re- 
moved by different crops, 484, 485 ; 
chemical condition of, in soil, 89 ; 
lodge in seed, 491 ; in soil, 87. 

Fertility, of the soil, 65-97 ; poten- 
tial, of soil, 214, 549 ; properties 
necessary for, 66 ; supply of oxy- 
gen necessary for, 81. 

Field experiments, 545, 548 ; educa- 
tional value of, 547 ; on rate of 
nitrification, 187. 

Finger-and-toe prevented by lime, 
461. 

Fire-fang in farmyard manure, 264. 

Fischer on absorption of plant-food, 
55. 

Fish-guano, 320-323 ; application of, 
323 ; consumption of, 152 ; manu- 
facture of, 321 ; nitrogen in, 321 ; 
phosphoric acid in, 321 ; production 
of, 322 ; source of nitrogen, 152 ; 
value of, 322. 

Fixers, 246 ; chemical reactions with, 
284. 

Fleece, potash in, 217. 

Fleischer, Professor, on solubility of 
phosphates, 408. 

Flesh-guano, 320. 

Flint Island guano, 309. 



INDEX. 



579 



Flitcham experiments on growth of 

wheat, 500. 

Floated bones, 362, 365. 
Florida phosphate, 378. 
Fluorapatite, composition of, 210. 
Food, consumed by pigs, 281 ; dry 

matter of, voided in dung, 228 ; 

percentage of, in excrements, 281. 
Food-constituents, plant, necessary 

for nitrification, 170. . 
Forbes, David, on nitrate - fields of 

Chili, 334. 
Forest-soils, absence of nitrification 

in, 193. 
Fowl-dung, 320, 326; analysis of, 

331. 
Fownes on phosphoric acid in rocks, 

202. 
Frankland, P. F., experiments on 

nitrification, 52, 167, 198. 
Franklin, Benjamin, experiment of, 

with gypsum, 462. 
Frey Bentos, meat-meal guano from, 

324. 

Gallopagos Islands, guano deposits 
at, 327. 

Garden earth, absorptive power of, 
98 ; ammonia in, 128. 

Gas-liquor, ammonia in, 353. 

Gas-works, ammonia from, 353, 358. 

Gases, absorbed by soils, 81 ; present 
in soil, 100. 

Gazzeri on retention by soil of plant - 
food, 57. 

Geese-dung, analysis of, 331. 

Geic acid in humus, 47. 

Gelatin, nitrification in, 182 ; from 
bones, 364. 

Germany, agricultural research in, 
32 ; bones imported from, 360 ; 
manufacture of meat-meal guano 
in, 324. 

Germination, influence of temperature 
on, 76 ; oxygen necessary for, 81. 

Gilbert, Sir J. Henry, on barley- 
manuring, 496 ; on Liebig's mineral 
theory, 28 ; on manuring of po- 
tatoes, 520 ; Presidential address 
of, 61 ; and see Lawes and Gilbert. 

Glauber on artificial production of 
nitre, 164. 

Glue, 364. 

Glycin, assimilated by plants, 47. 



Glycocoll, experiments with, 46. 

Gneiss, 106 ; phosphoric acid in, 207. 

Grandeau, Professor, on forms of 
plant-food in soil, 107 ; on loss of 
phosphoric acid, 207. 

Granite, 105 ; in guano, 303 ; phos- 
phoric acid in. 202, 211 ; potash in, 
214. 

Grass, Bangor experiments on, 508 ; 
effect of manure on, 505 ; influence 
of farmyard manure on, 506 ; man- 
uring of, 504-510. 

Gray, Asa, on transpiration by plants, 

Great Cayman guano, 379. 

Green manures, 113. 

Grouven on guano, 313. 

Guanape Island guano, 302, 327 ; 
nitrogen in, 329 ; phosphoric acid 
in, 329. 

Guanine, 304 ; experiments with, 46. 

Guano, 293-331 ; action of, as a man- 
ure, 312 ; adulteration of, 318 ; ap- 
plication of, 315 ; bat, 325 ; com- 
position of, 305, 329 ; crust, 308 ; 
deposits of the world, 327 ; dis- 
solved, 310; equalised, 309; fer- 
mentation of, 299 ; fertilising con- 
stituents in, 314; fish, 320-323; 
importance of, in agriculture, 293 ; 
inequality in composition of, 309 ; 
influence of, on farming, 294 ; meat- 
meal, 324 ; mode of application of, 
315 ; nitrification in, rate of, 192 ; 
nitrogenous, 300-308 ; origin of, 
297; Peruvian, 300-306; phos- 
phatic, 308 ; quantity to apply, 
317 ; rectified, 311 ; so-called, 320 ; 
source of phosphoric acid, 202 ; 
source of potash, 219 ; value of, as 
a manure, 296 ; variation in com- 
position of, 299. 

Gulf of Mexico, guano deposits at, 
328. 

Gulls, guano from, 297. 

Gunning on sources of plant-nitrogen, 
42. 

Gunpowder, exports of, 149 ; nitrogen 
lost in, 149 ; production, annual, 
of, 149 ; saltpetre in, 149, 333. 

Gypsum, 462-464 ; absorptive power 
of, 98 ; action of, mode of, 462 on 
nitrification, 173 ; an adulterant of 
guano, 319 ; as a fixer, 246, 247, 



580 



INDEX. 



285 ; decomposes double silicates, 
463 ; favourable to clover, 464 ; 
as an oxidising agent, 464. 

Hales, Stephen, theory of, on plant- 
growth, 8. 

Hampe, Dr, on nitrogen in plants, 46. 

Harting on sources of plant-nitrogen, 
42. 

Heat, of soils, 76-78 ; of fermenta- 
tion, 78. 

Heiden, Dr, on application of farm- 
yard manure, 265 ; on fixation of 
bases and acids by soil, 59 ; ou loss of 
ammonia from dung, 249 ; on per- 
centage of food voided by animals, 
253 ; on straw as litter, 244, 249. 

Hellriegel, on amount of water in 
soils, 75 ; on barley, 498 ; on ni- 
trogen in plants, 44. 

Helmout, Van, theory of, on source 
of plant-food, 4. 

Henslow, Professor, on coprolites, 
374. 

Heraus on organisms in soil, 95. 

Herbage, effect of manure on, 505. 

Herrings as manure, 321. 

Herve-Mangon, experiments on action 
of light on plants by, 38. 

Hilgeustock on tetracalcic phosphate, 
405. 

Hippuric acid, experiments with, 46 ; 
in farmyard manure, 257. 

Hire, De la, on evolution of gases by 
plants, 11. 

Hofmeister on horse excrements, 
243. 

Hoof-guano, source of nitrogen, 152. 

Hoofs and horns, manure from, 425. 

Hops, manuring of, 528 ; potash re- 
moved by, 217 ; slow-acting man- 
ures benefit, 528. 

Horn, capable of nitrification, 182 ; 
as manure, 425 ; nitrogen in, 426 ; 
phosphoric acid in, 426. 

Hornblende, 105. 

Horse-dung, alkalies in, 226 ; com- 
position of, in dry state, 227 ; hot, 
225 ; nitrogen in, 225, 226 ; phos- 
phoric acid in, 226 ; water in, 225, 
226. 

Horse-manure, 242 ; amount produced 
per day, 243 ; amount produced per 
year, 243 ; analyses of. 283 ; dry 



matter in, 243 ; dry nature of, 245 ; 
fermentation rapid in, 245 ; mineral 
matter in, 243; nitrogen in, 243, 

Horse-urine, alkalies in, 230 ; com- 
position of, in dry state, 231 ; fer- 
tilising ingredients in, 232 ; nitrogen 
in, 230 ; phosphoric acid in, 230 ; 
water in, 230. 

Hosaus on assimilation of ammonia, 
50. 

Howland Island guano, 309, 328 ; 
phosphoric acid in, 330. 

Huanillos, guano from, 302, 327 ; 
nitrogen in, 330 ; phosphoric acid 
in, 330. 

Huano, 297. 

Hueppe on organisms in soil, 95. 

Hughes, John, on bracken-fern as 
litter, 241 ; on composition of 
bracken, 283. 

Humates in farmyard manure, 259. 

Humboldt, A., discovery of Peruvian 
guano by, 300. 

Humic acid in farmyard manure, 
258 ; in humus, 47. 

Humin in humus, 47. 

Humus, absorptive power of, 68, 98 ; 
evaporation from, 99 ; nature of, in 
soil, 47 ; soils improved by addi- 
tion of, 273. 

Huou Island guano, 309, 328 ; phos- 
phoric acid in, 330. 

Huxtable and Thompson on retention 
of plant-food by soil, 57. 

Hydrated silicates, 107, 459. 

Hydrochloric acid as a fixer, 245. 

Hydrogen, amount of, in plants, 40 ; 
source of, in plants, 40. 

Hygroscopic power of soils, 75. 

Ichaboe guano, 307 ; nitrogen in, 

329 ; phosphoric acid in, 329. 
Independence Bay guano, 302, 327 ; 

nitrogen in, 329 ; phosphoric acid 

in, 329. 

India, nitre soils of, 162. 
Indirect manures, 113, 114, 449-473. 
Ingenhousz, John, experiments by, on 

nitrogen in plants, 41 ; on oxygen 

evolved by plants, 12. 
Insoluble phosphate, 386; value of, 396. 
Iodine, in ash of plants, 55 ; in 

nitrate of soda, 340, 342. 



INDEX. 



581 



Iquique, nitrate of soda from, 333. 
Iron in ash of plants, 54 ; necessary 

for plant-growth, 55 ; reversion in 

superphosphates caused by, 390, 

399. 
Iron-works, ammonia from, 353, 355, 

358. 
Irrigation, 431 - 433 ; intermittent, 

434 ; subsoil, 432. 

Jamieson, Professor, experiments 
with coprolites, 380. 

Jarvis Island guano, 309, 328 ; phos- 
phoric acid in, 330. 

Jersey, manuring of potatoes in, 521. 

Johnson^ Professor S. W., on appli- 
cation of superphosphate, 395 ; on 
Earl Dundonald, 13 ; on nitrogen 
in buffalo-horn shavings, 426 ; on 
nitrogen in soils, 123 ; on solubil- 
ity of basic slag, 408 ; value of 
organic nitrogen to plant, 46. 

Jurgensen on nitrogen in excreta, 234. 

Kainit, as a fixer, 247 ; potash in, 
percentage of, 214, 220, 421 ; rate 
of application of, 423. 

Kaolin clay, analysis of, 104. 

Karmrodt/ analysis of Chincha Island 
guano, 305 ; of concretionary nod- 
ules, 328. 

Karnallite, potash in, 220. 

Kellner, experiments on nitrification 
by, 52. 

Kelp, potash in, 420. 

Kieserite, 420. 

Kinuaird, Lord, experiments by, with 
farmyard manure, 289. 

Kitchen-garden soil, nitrogenous mat- 
ter in, 122. 

Knop on condition of nitrates in 
soil, 138. 

Koosaw River, phosphates from, 376. 

Kreatin assimilated by plants, 47. 

Kuria Muria guano, 309, 328. 

Labrador, guano deposits at, 328. 
Labradorite, 214 ; potash in, 220. 
Lacepede Island guano, 309, 328 ; 

phosphoric acid in, 330. 
Lahn phosphate, 379. 
Lava, phosphoric acid in, 202, 211. 
Lawes, Sir J. B., and Gilbert, early 

researches of, at Rothamsted, 34 ; 



experiments with farmyard man- 
ure, 271 ; experiments with Per- 
uvian guano, 301 ; inauguration of 
Rothamsted experiments by, 33 ; 
on composition of farmyard man- 
ure, 291 ; on manuring of wheat, 
483 ; on motion of plant's sap, 56 ; 
on percentage of food in excreta, 
233 ; on rate of nitrification, 186 ; 
on sources of plant-nitrogen, 43 ; 
on sulphate of ammonia, 356 ; on 
unexhausted manures, 550, 557-559. 

Lawes, Sir J. B., experiments with 
guano by, 301 ; manufacture of 
superphosphate by, 382 ; on ap- 
plication of superphosphate, 395 ; 
on bones, 359 ; on composition of 
farmyard manure, 291 ; on farm- 
yard manure, 477 ; on loss of ni- 
trates, 142 ; on sources of nitrogen, 
154. 

Leather, as manure, 428 ; nitrogen 
in, 428. 

Leaves, dried, as litter, 242; nitro- 
gen in, 242 ; phosphoric acid in, 
242 ; potash in, 242. 

Legrange, Charles, on extent of ni- 
trate-fields, 343. 

Leguminous plants, benefited by basic 
slag, 414 by potash, 523 ; fixation 
of free nitrogen by, 42 ; gain of 
nitrogen with, 135 ; manuring of, 
522-527, 530 ; nitrogenous manures 
hurtful to, 523. 

Lehmann on ammonia as plant-food, 
50, 352. 

Leipzig, bones from, 361. 

Leones, guano deposits at, 327. 

Leucite, potash in, 220. 

Lias chalk, phosphoric acid in, 211. 

Liebig, criticism of humus theory by, 
25 ; dissolved bones discovered by, 
361 ; first report to British Associ- 
ation, 24 ; manufacture of super- 
phosphate from bones by, 359 ; 
mineral theory of, 26-29 ; on am- 
monia as a manure, 352 ; on im- 
portation of bones by Britain, 360 ; 
researches of, in agricultural chem- 
istry, 23-32 ; services of, to agri- 
cultural chemistry, 31 ; theory of 
manures by, 29 ; theory of, on ro- 
tation of crops, 29. 

Light, action of, on plant-growth, 38. 



582 



INDEX. 



Lime, 449-461 ; abundant occurrence 
of, 452 ; action of, 461 contradic- 
tory, 450 not thoroughly under- 
stood, 449 on nitrogenous organic 
matter, 460 on soil's texture, 455 ; 
antiquity of, as a manure, 449 ; 
binding effect of, 457 ; biological 
action of, 459 ; caustic, 453 ; chem- 
ical action of, 457 ; decomposes 
minerals, 458 ; different forms of, 
453 ; effect of, on soils, 112 ; fixed 
by soils, 58 ; in ash of plants, 54 ; 
mechanical functions of, 455 ; mild, 
453 ; necessary for nitrification, 
171, 459 for plant-growth, 55, 
450 ; neutralises acidity in soils, 
458 ; phosphates of, 385-388 ; pig 
excrements contain, 281 ; prevents 
clay puddling, 456 ; returned to 
soil, 452 ; soils contain, 450-452. 

Limestone, analyses of, 106 ; evapora- 
tion of water from, 99 ; occurrence 
of, 452. 

Linseed, imports of, 153 ; manurial 
constituents of, 282. 

Linseed-cake, manurial constituents 
of, 282. 

Liquid manure, 442-444. 

Lithia in ash of plants, 55. 

Litter, loam as, 239 ; peat as, 240 ; 
straw as, 236 ; uses of, 236. 

Lloyd on fattening animals, 253. 

Loam, as litter, 239 ; evaporation of 
water from, 99 ; poor in fertilising 
matter, 239. 

Lobos, guano deposits at, 327. 

Lobos de Afuera guano, 302, 327. 

Macabi Island guano, 302, 327 ; ni- 
trogen in, 329 ; phosphoric acid in, 
329. 

Maercker, Professor, on destruction 
of nitrifying organisms, 177. 

Magnesia, fixed by soils, 58 ; in ash 
of plants, 54 ; in pig excrements, 
281 ; necessary for nitrification, 
171; necessary for plant -growth, 
55 ; sulphate of, as a fixer, 246, 285. 

Maize, absorbs ammonia, 352 ; fer- 
tilising ingredients removed from 
soil by, 485 ; manurial constituents 
in, 282 ; source of nitrogen, 153. 

Maiden Island guano, 309, 328 ; 
phosphoric acid in, 330. 



Malpighi on importance of atmo- 
spheric air for germination, 39. 

Malt-dust, manurial constituents in, 
282. 

Manganese, oxide of, in ash of plants, 
04. 

Mangels, fertilising ingredients re- 
moved from soil by, 485 ; guano a 
manure for, 318 ; mauurial con- 
stituents in, 282 ; manuring of, 
346, 511, 513, 514 ; Rotham- 
sted experiments on growth of, 
568. 

Manitoba soils, nitrogen in, at various 
depths, 156 ; rate of nitrification 
in, 186. 

Manure, cow, 247 ; farmyard, 223- 

292 ; horse, 243 ;' liquid, 442-444 ; 
meaning of word, 109 ; pig, 250 ; 
sewage, 430-441 ; sheep, 251 ; stable, 
from peat-moss, 283 wheat-straw, 
283. 

Manures, action of, 61 ; analysis of, 
interpretation of, 539-544 ; appli- 
cation of, 474-492 ; method of, 531- 
538 ; cash prices of, 555 ; equal 
distribution of, 531 ; functions of, 
109 ; increase soil - fertility, 474 ; 
intrinsic value of, 545 ; lasting 
effects of, 483 ; methods of valuing, 
544 ; minor artificial, 424 - 429 ; 
mixing of, 531-538 ; nitrogenous, 

293 - 359 ; phosphatic, 359 - 417 ; 
potassic, 418 - 423 ; quantities of, 
applied to oats, 504 ; unexhausted, 
549-552, 558 ; units for determining 
commercial value of, 554 ; valuation 
of, 539-559 ; value of, deduced from 
experiments, 548 ; various classes 
of, 111-114. 

Manurial constituents of various 
foods, 282. 

Manurial ingredients, unit value of, 
544. 

Manuring of, barley, 495-498 ; beans, 
525-527, 530 ; cabbages, 528 ; cere- 
als, 493-504 ; clover, 524 ; common 
farm crops, 493-530 ; grass, 504- 
510 ; hops, 528 ; leguminous crops, 
522-528 ; mangels, 511, 513, 514 ; 
oats, 493 - 504 ; peas, 527 ; pota- 
toes, 517-522 ; roots, 510 - 517 ; 
turnips, 510, 511, 513-517 ; wheat, 
499-501. 



INDEX. 



583 



Maraeaibo guano, nitrogen in, 330 ; 
phosphoric acid in, 330. 

Marl, phosphoric acid in, 211. 

Marsh -gas from farmyard manure, 
258. 

Meadow -hay, fertilising ingredients 
removed from soil by, 485 ; man- 
urial constituents in, 282 ; Roth- 
amsted experiments on manuring 
of, 570. 

Meadow-land, benefited by basic slag, 
414, 508 ; manuring of, 508 ; Nor- 
folk experiments on, 509. 

Meat-meal guano, 320, 324 ; com- 
position of, 152 ; imports of, 324 ; 
manufacture of, 324 ; nitrogen in, 
324 ; phosphoric acid in, 324 ; rate 
of nitrification in, 192 ; source of 
nitrogen, 152 ; value of, 324. 

Mechi on liquid manure, 442. 

Mejillones guano, 309, 327 ; phos- 
phoric acid in, 330. 

Mene, on sources of plant - nitrogen, 
42. 

Menhaddo. guano manufactured from, 
322. 

Mexico phosphate, 308, 328. 

Mica, analysis of, 105 ; potash in, 
214, 220. 

Micro-organisms, convert ammonia 
into nitrous acid, 167 ; convert 
nitrous acid into nitric acid, 168 ; 
effect fermentation, 80 ; effect fix- 
ation of free nitrogen, 44 ; effect 
nitrification, 161 ; oxidising power 
of, 197. 

Mild lime, 453. 

Milk, nitrification in albuminoids of, 
182 ; nitrogen removed in, 147 ; 
phosphoric acid removed in, 207 ; 
potash removed in, 218. 

Mineral phosphates, 373-381 ; value 
of, as a manure, 380. 

Mineral salts necessary for nitrifica- 
tion, 52. 

Minor artificial manures, 424-429. 

Mixing manures, 532-538 ; ammonia 
lost in, 533 ; nitric acid lost in, 
536 ; phosphates reverted in, 536. 

Moisture, atmospheric, action on 
guano, 300 ; in farmyard manure, 
260 ; in manures, 543 ; necessary 
for nitrification, 52, 176. 

Molds, 94. 



Mona guano, 309. 

Mond, Ludwig, on nitrogen in coal, 
354. 

Monks guano, 327; phosphoric acid 
in, 330. 

Monocalcic phosphate, 386 ; formula 
of, 398 ; molecular composition of, 
398 ; percentage composition of, 
398 ; reversion of, with iron and 
alumina compounds, 399 with 
tricalcic phosphate, 399. 

Mulder on humus in soil, 47, 126. 

Miiller, A., on nitrogen in soil, 121, 
124. 

Munro, Dr J. M. H. , on nitrification, 
52 ; on sewage-sludge as manure, 
439 ; on urine voided, 292. 

Muntz, on ammonia in air, 118 ; on 
nitrifying organisms in soil, 180 ; 
on oxidising power of micro-organ- 
isms, 197. 

Muriate of potash, application of, 
423 ; forms calcium chloride, 422 ; 
harmful effects of, 421 ; more con- 
centrated than sulphate, 422. 

Mustard, 139. 

Navassa phosphate, 308, 328, 379. 

Nesbiton composition of guano, 301, 

New Granada, guano deposits at, 327. 

New Zealand, meat-meal guano from, 
324. 

Nile, nitrates in waters of, 159. 

"Nitraries,"163. 

Nitrate - fields, appearance of, 340 ; 
origin of, 334. 

Nitrate of soda, 332 - 351 ; amount 
exported from Chili, 151, 332, 351 ; 
amount imported into Britain, 151, 
351 ; appearance of fields of, 340 ; 
application of, 347 ; Chili and Peru 
chief source of, 161 ; composition 
of, 343 ; crops suited by, 346 ; dis- 
covery of deposits of, 333 ; extent 
of deposits of, 342 ; encourages deep 
roots, 344 ; formation of fields of, 
334-340 ; method of applying, 347 ; 
method of mining, 341 ; nitric acid 
in, source of, 337 ; nitrogen in, 
percentage of, 343 ; not an exhaust- 
ing manure, 345 ; origin of fields of, 
334 ; properties of, 343 ; quantity 
to apply, 348 ; shipments of, 351 ; 
soils benefited by, 348 ; source of 



584 



INDEX. 



nitrogen, 150 ; top - dressing with, 
o44. 

Nitrates, amount lost by drainage, 
140 ; amount produced at different 
times, 189 ; amount in soil, 129 ; 
conditions diminishing loss of, 139 ; 
constantly formed in soil, 138 ; in 
barley -soils, 158 ; in cropped soils, 
130, 157 ; in drainage-waters, 160, 
188 ; in fallow-soils, 129 ; in man- 
ured wheat-soils, 131, 157 ; in soil, 
129, 162 ; lost by drainage, 137 ; 
most formed in summer, 139 ; 
nitrogen as, in Rothamsted soils, 
198 ; position of, in soil, 188 ; 
quantity formed in fallow -fields, 
188. 

Nitre, beds, 163 ; occurrence of, 162 ; 
soils of India, 162. 

Nitric acid, amount of, supplied to 
soil by rain, 155 ; derived from sea- 
weed, 337 ; formed from ammonia, 
118 ; formed from nitrous acid, 168 ; 
in farmyard manure, 259 ; in soil, 
128 ; lost in mixing manures, 536 ; 
most important nitrogen compound 
for plants, 161 ; relation of, to 
plants, 50 ; source of, in nitrate 
of soda, 337. 

Nitrification, 51, 52, 161-198 ; action 
of gypsum on, 173 ; alkalinity 
necessary for, 172 ; in asparagin, 
182 ; bearing of, on agriculture, 
193 ; in bones, 182 ; cause of, 165 ; 
conditions favourable for, 170 ; 
deuitrification, 177 - 179 ; effected 
by micro-organisms, 51, 167 ; in 
ethylamine, 182 ; in fallow-fields, 
184 ; food - constituents necessary 
for, 170 ; field experiments on rate 
of, 187 ; in gelatin, 182 ; in horn, 
182 ; laboratory experiments on 
rate of, 185 ; in manures, 190, 192 ; 
in milk albuminoids, 182 ; mineral 
salts necessary for, 52 ; moisture 
necessary for, 52, 176 ; old theories 
on, 196 ; organic matter not neces- 
ary for, 169, 196 ; oxygen necessary 
for, 52, 173 ; plant-roots promote, 
181 ; in rape-cake, 182 ; rate of, 
183 ; rotation of crops, bearing of, 
on, 195 ; soil best suited for, 192 ; 
in subsoils, conditions favourable 
for, 181 ; substances capable of, 181; 



in summer, 183 ; sunlight, effect 
of, on, 176 ; temperature necessary 
for, 52, 175 ; in thiocyanates, 182 ; 
hi urea, 182 ; in wool, 182. 

Nitrifying organisms, depth found 
at in soil, 180 ; distribution of, in 
soil, 179 ; effect of poisons on, 176 ; 
organic matter not required by, 169. 

Nitrobaeter, 167. 

Nitrogen, 115-160 ; absorbed by soil, 
81, 131 ; accumulates in pastures, 
134 ; in air, 116 ; as ammonia in 
soils, 127 ; amount of, in plants, 
40; amount of, in soil, 123; arti- 
ficial supply of, 150 ; in bat guano, 
325 ; in bones, 363, 364 ; combined, 
in air, 118 ; combined, in rain, 119, 
155 ; condition of, in manures, 540 ; 
converted into nitrates in soil, 51 ; 
in cow - dung, 226 - 228 ; in cow 
excrements, 278 ; in cow - urine, 
230 ; difference between surface and 
subsoil, 126 ; different forms of, 45, 
116 ; dissolved in rain, 131 ; in 
dried blood, 424 ; in farmyard 
manure, 260; in fish -guano, 321; 
fixation of free, 136 ; forms of, in 
plants, 491 ; free, relation of, to 
plant, 117; gain of, with legumin- 
ous crops, 135 ; in guanos, 329 ; 
in hoofs and horns, 426 ; in horse- 
dung, 226 - 228 ; in horse - man- 
ure, 243 ; in horse - urine, 230 ; 
importance of, in soil, 88 ; in lean 
flesh, 424 ; in leather, 428 ; least 
abundant of manurial ingredients 
in soil, 271 ; loss of, artificial sources 
of, 144 ; loss of, by crops, 144 ; 
loss of, on farm, 146 ; loss of, 
sources of, 137-150 ; loss of, total 
amount of, 142 ; lost in the arts, 
148; lost in free condition, 141; 
lost in treating farmyard manure, 
146; lost in milk, 147; lost by 
retrogression, 142 ; in Manitoba 
soils, 156 ; in meat - guano, 324 ; 
nature of, in soil, 124 ; as nitrates 
in soil, 128 ; as nitrates in cropped 
soils, 130, 157 ; as nitrates in Eoth- 
amsted soils, 198 ; as nitrates 
in wheat - soils, 157 ; in nitrate of 
soda, 343 ; nitric, in soil, 128 ; 
organic, absorbed by plants, 47 ; 
organic, in soil, 125 ; original 



INDEX. 



585 



source of, m soil, 133 ; in oxen 
excrements, 280 ; in pasture-lands, 
158 ; peat-soils richest in, 123 ; in 
Peruvian guano, 302, 306, 307, 329 ; 
in pig-dung, 226-227 ; position of, 
in agriculture, 115-160; relative 
manurial value of, 556; Rotham- 
sted experiments on, 115 ; in 
scutch, 427 ; in sewage, 431 ; in 
sewage-sludge, 439 ; in sheep -dung, 
226 - 228 ; in sheep excrements, 
280 ; in sheep-urine, 230 ; in soil, 
120 ; in soil, portion of, easily 
nitrifiable, 187 ; in soils at various 
depths, 156 ; in soot, 428 ; source 
of, in plants, 15, 16, 40-52 ; sources 
of soil, 131-137 ; in straw, 237, 243 ; 
in subsoil, 121 ; in surface - soil, 
121 ; in swine-urine, 230 ; in wool- 
len rags, 427. 

Nitrogenous guano, 300-308, 329. 

Nitrogenous manures, application of, 
478 ; benefit cereals, 494 ; hurtful 
to leguminous crops, 523. 

Nitrogenous organic substances, in 
Chincha guano, 305 ; in concretion- 
ary nodules, 328. 

Nitros omon as, 167. 

Nitrous acid, converted into nitric 
acid, 168 ; formed from ammonia, 
167. 

Nobbe, on fixation of free nitrogen, 
136 ; on potash in soil, 108. 

Nollner on origin of nitrate - fields, 
339. 

Norfolk, coprolites from, 374 ; experi- 
ments on barley, 497 on meadow- 
land, 509 on turnips, 513. 

North America, guano from, 298, 328. 

Norwegian apatite, 375. 

Oak-tree, water transpired by, 71. 

Oat-straw, composition of, 238 ; man- 
urial constituents in, 282. 

Oats, Arendt's experiments with, 503 ; 
avenine in, 503 ; fertilising ingre- 
dients removed from soil by, 485 ; 
hardy crop, 502 ; manurial con- 
stituents in, 282 ; manuring of, 
501-504 ; nitrogen removed in crop 
of, 148 ; require mixed nitrogenous 
manures, 502 ; source of nitrogen, 
153 ; Rothamsted experiments on 
growth of, 567. 



Oficinas, 342. 

Ohlendorff, introduction of dissolved 
guano by, 311. 

Oilcakes, imports of, 153 ; source of 
nitrogen, 153. 

Oil-seeds, source of nitrogen, 153. 

Oligoclase felspars, 103, 214 ; com- 
position of, 103 ; potash in, 220. 

Organic matter, in bones, 363 ; in 
dung, 228, 260 ; in manures, 543 ; 
not necessary for nitrifying organ- 
ism, 169. 

Orthoclase felspars, 103, 214 ; com- 
position of, 103 ; potash in, 220. 

Ox-dung, fertilising ingredients in, 
for food consumed, 228. 

Ox-urine, fertilising ingredients in, 
232. 

Oxalic acid in guano, action of, 330. 

Oxen, excrements of, 280 ; food aided 
by, 280 ; solid excreta voided by, 
280 ; urine voided by, 280. 

Oxidation, 79 ; products of, 79, 80. 

Oxygen, absorbed by plant-roots, 81 ; 
absorbed by soil, 81 ; evolved by 
plants, 11 ; necessary for fertility, 
81 ; necessary for nitrification, 52, 
173 ; percentage of, in plants, 39 ; 
source of, in plants, 39. 

Pabellon de Pica, guano from, 298, 
302, 327; nitrogen in, 330; phos- 
phoric acid in, 330. 

Pacific Islands, guano from, 298. 

Pacific Ocean, sea-weed in, 339. 

Palagonite as potash manure, 213. 

Palm-kernel meal, manurial constit- 
uents in, 282. 

Pasteur, on fermentation in urine, 
255 ; on nitrification, 166. 

Pastures, accumulation of nitrogen in, 
134 ; benefited by basic slag, 414 ; 
deficient in lime, 451 ; effect of 
manure on herbage of, 505 ; nitro- 
gen in, 158 ; permanent, 138, 194 
manuring of, 509 ; season influ- 
ences, 507 ; soil influences, 507. 

Patagonian guano, 308, 327 ; nitrogen 
in, 330 ; phosphoric acid in, 330. 

Patent phosphate meal, 405. 

Patillos, guano deposits at, 327. 

Patos Island, guano deposits at, 328 ; 
phosphoric acid in, 330. 

Patterson on superphosphate, 399. 



586 



INDEX. 



Payen and Boussingault on composi- 
tion of dried flesh, 425. 

Peas, mamirial constituents in, 282 ; 
manuring of, 527 ; phosphorus in, 
205 ; source of nitrogen, 153. 

Peat, absorbing properties of, 239 ; 
adulterant of guano, 317 ; analysis 
of stable-manure from, 281 ; litter, 
239 ; nitrogen in, 240 ; retaining 
properties of, 240 ; soils, 123. 

Pelicans, guano from, 297. 

Penguin Island guano, 330 ; nitrogen 
in, 330 ; phosphoric acid in, 330. 

Penguins, guano from, 297. 

Percival on carbonic acid in plants, 
12. 

Peru, guano deposits in, 327 ; guano 
first used in, 297 ; nitrate of soda 
from, 161, 162. 

Peruvian guano, 300-306 ; appearance 
of, 303 ; composition of, 304-306 ; 
deposits of, 301 ; imports of, 151, 
297 ; source of nitrogen, 151. 

Peters and Eichhorn on solvent power 
of salt, 471. 

Petzholdt on sources of plant's nitro- 
gen, 42. 

Pfeffer on action of light on plant - 
growth, 38. 

Phoenix Island guano, 309. 

Phosphate of iron in Chincha guano, 

Phosphate of lime, in Algerian phos- 
phate, 379 ; in apatite, 374 : in 
Belgian phosphate, 377 ; in bones, 
364 ; in Cambridge coprolites, 374 ; 
in Carolina phosphates, 376 ; in 
crust guanos, 379 ; in Estremadura 
phosphate, 375 ; in Florida phos- 
phate, 378 ; hi French phosphates, 
379 ; in Lahn phosphates, 379 ; in 
Somme phosphate, 378 ; reverted in 
mixing manures, 537. 

Phosphates of lime, 385-388, 398 ; im- 
portance of mechanical condition 
of, 542. 

Phosphates, mineral, 373-381 ; imports 
of, 381 ; value as a manure, 380. 

Phosphatic guano, 308, 330. 

Phosphatic manures, application of, 
480. 

Phosphoretted hydrogen in farmyard 
manure, 258. 

Phosphoric acid, 199-211 ; in ash of 



plants, 54 ; in basic slag, 404 ; in 
bat guano, 325 ; in bones, 363 ; 
condition of, in soil, 203 ; in cow- 
dung, 226-228; in cow excre- 
ments, 280 ; in cow-urine, 230 ; in 
farmyard manure, 260 ; in fish- 
guano, 321 ; fixed by soils, 58 ; gain 
of, 208 ; in guano, percentage of, 
329, 330 ; guano a source of, 202 ; 
in hoofs and horns, 426 ; in horse- 
dung, 226-228; in horse - nrine, 
230; importance of, 88; loss of, 
artificial sources of, 206 by drain- 
age, 206 in farmyard manure, 208 
in milk, 207 in sewage, 208 
sources of, in agriculture, 205 ; in 
meat-guano, 324 ; mineral sources 
of, 200; necessary for plant-growth, 
55 ; occurrence of, in animals, 205 
in nature, 199 in plants, 204 in 
soil, 203 ; in oxen excrements, 280 ; 
in pig-dung, 226, 227 ; in pig excre- 
ments, 281; in pig-urine, 230; po- 
sition of, in agriculture, 199-211 ; 
relative trade values of, in manures, 
400 ; in rocks, 202, 211 ; in sewage- 
sludge, 441; in sheep-dung, 226 
228 ; in sheep excrements, 280 ; 
in sheep-urine, 230; statement of, 
in analyses of manures, 541. 

Phosphorite, 201, 374. 

Phosphorus, in albuminoids, 205; in 
animals, 205; in beans, 205; in 
peas, 205; in plants, 204; in pig- 
iron, 401. 

Physical properties of soils, 66-87. 

Pichard on action of gypsum on ni- 
trification, 173. 

Pig-dung, composition of, 226 ; in dry 
state, 227. 

Pig excrements, 281 ; composition of, 

Pig-manure, 250; amount produced 
per day, 251 ; mineral matter in, 
251 ; nitrogen in, 251 ; poor in 
nitrogen, 251. 

Pig-urine, composition of, 230 in dry 
state, 231. 

Pigeon-dung, 320, 325; analysis of, 
331. 

Pigs, excrements of, 281; food con- 
sumed by, 281. 

Pisagua, nitrate-fields at, 340. 

Plant, action of light on, 38 ; amount 



INDEX. 



587 



of hydrogen in, 40 nitrogen in, 
40 oxygen in, 40 ; ash constituents 
of, 53-55; carbon fixed by, 37, 38; 
food, absorption of, by, 55; phos- 
phoric acid in, 204 ; potash in, 216 ; 
proximate composition of, 36; re- 
lation of ammonia to, 48-50 ; source 
of hydrogen in, 40 nitrogen in, 
40-52 oxygen in, 39, 40. 

Plant-food, absorption of, 490; amount 
of soluble, in soil, 100 ; early theories 
on source of, 4; retained by soil, 
57. 

Plant-roots, grow downwards, 84; 
nitrification promoted by, 181; 
openness required by, 83; room 
required by, 85; soil in relation 
to, 84. 

Pliny, on lime as a manure, 449 ; on 
salt as a manure, 465. 

Pockets a source of phosphoric acid, 
202. 

Poisons, effect of, on nitrifying organ- 
isms, 176. 

Polstorff on ash constituents of plants, 
53. 

Polyhallite, potash in, 220, 420. 

Porphyry, in guano, 303 ; phosphoric 
acidX 202, 211. 

Potash, 212-220, 418-423; in ash of 
plants, 54 ; in barilla, 420 ; chloride 
of, 218 ; condition of, in soil, 216 ; 
in cows' excrements, 280 ; in drain- 
age-waters, 217 ; in farmyard man- 
ure, 260 ; in felspars, 220 ; in fleece, 
217 ; fixed by soils, 58 ; importance 
of, in soil, 88; in kelp, 420; less 
important than phosphoric acid, 
212 ; manures, 218, 418-423 ; muri- 
ate of, 218, 421 ; necessary for nitri- 
fication, 171 ; necessary for plant- 
growth, 55; occurrence of, 213; in 
ocean, 213; in oxen excrements, 
280; in pig excrements, 280; in 
plants, 216 ; position of, in agricul- 
ture, 212-220; relative manurial 
value of, 556; Scottish soils sup- 
plied with, 419 ; in sheep excre- 
ments, 280; soda replaces, 466; 
sources of loss of, 217 ; in Stassfurt 
salts, 214 ; statement of, in analyses 
of manures, 542 ; in sugar-beet ref- 
use, 219 ; sulphate of, 218, 421 ; in 
wood-ashes, 218, 220, 419. 



Potash manures, 218, 418-423 ; appli- 
cation of, 422, 480 rate of, 423; 
barilla , as, 420; crops suited for, 
423 ; relative importance of, 418 ; 
soils suited for, 423; sources of, 
419 ; Stassfurt salts as, 420 ; wood- 
ashes a source of, 419. 

Potassium phosphate in concretionary 
nodules, 328. 

Potassium sulphate, in Chincha guano, 
305 ; in concretionary nodules, 328. 

Potatoes, effect of farmyard manure 
on, 520 ; fertilising ingredients re- 
moved from soil by, 485; grown 
with covered manure, 289 ; High- 
land Society's experiments on, 518 ; 
manurial constituents in, 282 ; man- 
uring of, 517-522 in Jersey, 529 
influences composition of, 521 ; po- 
tash removed in, 217 ; Rothamsted 
experiments on, 519, 571. 

Precipitated ammonium phosphate in 
concretionary nodules, 328. 

Precipitated phosphate, 330, 387. 

Precipitation, treatment of sewage by, 
436. 

Priestley, discovery of evolution of 
oxygen by plants, 11 ; on nitrogen 
in plants, 40. 

Prussiate of potash, manufacture of, 
353. 

Pugh on sources of plant-nitrogen, 
42. 

Punta de Lobos guano, 302 ; nitrogen 
in, 303 ; phosphoric acid in, 303. 

Punta de Patillos, guano deposits at, 
327. 

Pyroxene, potash in, 220. 

Quartz, evaporation of water from, 

99. 
Queensland, meat-meal guano from, 

324. 
Quercitan, experiments of, with 

roses, 8. 

Rape -cake, capable of nitrification, 
182 ; manurial constituents in, 282. 

Rape-seeds, imports of, 153. 

Raza Island guano, 328 ; phosphoric 
acid, 330. 

Rectified guano, 311. 

Relative trade values of phosphoric 
acid, 400. 



588 



INDEX. 



Resin in guano, 305. 

Retentive power of soils for water, 
70-73. 

Retrogression, nitrogen lost by, 142. 

Reverted phosphates, 389-391 ; deter- 
mination of amount of, 391 ; for- 
mation of, 387 ; value of, 391. 

Rhine, nitrates in waters of, 158. 

Rice-meal, an adulterant of guano, 
319 ; manurial constituents of, 282. 

Rocks, phosphoric acid in, 202. 

Roots, influence of manures on com- 
position of, 512 ; manuring of, 510- 
522 ; Norfolk experiments on, 513 ; 
potash removed in, 217. 

Rotation of crops, bearing of, on 
nitrification, 195. 

Rotations, phosphoric acid in, 290 ; 
potash removed in, 290. 

Rothamsted, alternate Avheat and 
bean rotation at, 524 ; ammonia in 
rain at, 49 ; barley experiments at, 
566 ; Broadbalk Field, alteration in 
composition of, 159 manuring of, 
159 produce of wheat on, 159 ; 
early experiments at, 33-36 ; ex- 
periments, 560 - 572 ; experiments 
with nitrate of soda at, 347 ; ex- 
periments on nitrogen question at, 
115 mangel - wurzel, 568 oats, 

567 potatoes at, 519 value of 
nitrogen in farmyard manure, 271 ; 
increase of nitrogen with manures 
at, 137, 513 ; nitrates in barley- 
soils of, 158 ; nitrates in cropped 
soils of, 130, 157 ; nitrates in drain- 
age of, 189 ; nitrates in wheat-soils 
of, 131, 157 ; nitrogen as nitrates 
in soils of, 129, 198 ; nitrogen, de- 
crease of, in soils, 159 ; nitrogen in 
pasture at, 126 ; pasture, increase 
of nitrogen in, 158 ; retrogression 
of nitrogen at, 142 ; soil, nature of, 
561 nitrogen in, at various depths, 
156 ; total amount of nitrogen lost 
at, 142 ; turnip experiments at, 

568 ; unmanured fallow-land loses 
nitrogen by drainage at, 141 ; wheat 
experiments at, 500, 562-565. 

Roy on sources of plant-nitrogen, 42. 
Rubidia in ash of plants, 55. 
Ruffle, John, on superphosphate, 388. 
Rye, manurial constituents in, 282. 
Rye-grass suited for sewage, 435. 



Rye-straw, summer, composition of, 
238 ; winter, composition of, 238. 

St Helena, experiments at, with 
Peruvian guano, 301. 

Saldanha Bay guano, 328 ; nitrogen 
in, 329 ; phosphoric acid in, 329. 

Salinas, 335. 

Salm - Horstmar, Prince, on water- 
culture, 54. 

Salt, 465-473 ; action of, on crops, 
472 ; adulterant of guano, 319 ; 
amount applied, 473 ; antiquity of 
use of, 465 ; an antiseptic, 468 ; 
application of, 472 ; clarifies water, 
470 ; coagulates clay, 470 ; decom- 
poses minerals, 470 ; a germicide, 
468 ; indirect action of, 468 ; me- 
chanical action of, 470 ; nature of 
action of, 465 ; not a necessary 
plant -food, 466 ; occurrence of, 
467 ; prevents rapid fermentation, 
471 ; quantity to apply, 473 ; sol- 
vent action of, 470 ; sources of, 468. 

Saltpetre, formation of, 164 ; occur- 
rence of, 215 ; plantations, 163. 

Sand, absorptive power of, 68 ; an 
adulterant of guano, 319 ; cal- 
careous, absorptive power of, 98 ; 
siliceous, absorptive power of, 98. 

Sandy soils deficient in lime, 451. 

Sandwich Islands, guano deposits at, 
328. 

Saragossa Sea, sea-weed in, 339. 

Saussure, De, on absorption of gases 
by soil, 81 ; on nitrogen in plants, 
41 ; researches on plant-food by, 15. 

Sawdust an adulterant of guano, 319. 

Scheibler, Professor, on basic slag, 
404. 

Schloesing and Muntz, on nitrifica- 
tion, 51, 166 ; experiments on rate 
of nitrification by, 185 ; on denitri- 
fication, 179 ; on ferments effecting 
nitrification, 167 ; on fixation of 
free nitrogen, 42 ; on ammonia in 
air, 119, 132 ; on nitrogen absorbed 
by soil from air, 132 ; on tempera- 
ture favourable for nitrification, 
175. 

Schoenite, potash in, 220. 

Schlibler, on absorptive power of 
soils, 98 ; on retentive power 'of 
soils, 98. 



INDEX. 



589 



Schulze on fixers, 246. 

Scutch, 427 ; manufacture of, 427 ; ni- 
trogen in, 427. 

Sea- weed, nitric acid in, 339. 

Seals, guano from, 297. 

Seed, fertilising ingredients lodge in, 
491. 

Seine, nitrates in waters of, 158. 

Senebier, Jean, on carbon in plants, 
12 ; on nitrogen in plants, 41. 

Sewage, 430-441 ; charcoal a filter for, 
437; crops suited for, 434; de- 
nitrification in, 179 ; dry matter 
in, 431 ; effects of continued appli- 
cations of, 433 ; filters for, 437 ; 
irrigation with, 431-433 ; nitrifica- 
tion in, 166 ; nitrogen lost in, 149 ; 
phosphoric acid lost in, 149 ; puri- 
fied by soils, 435 ; treatment of, by 
precipitation, 436 ; value of, as a 
manure, 430. 

Sewage-sick land, 433. 

Sewage-sludge, 438-441 ; as a manure, 
experiments with, 438 ; nitrogen in, 
439 ; phosphoric acid in, 439 ; pro- 
fitable treatment of, 441 ; value of, 
439 ; water in, 438. 

Shale -works, sulphate of ammonia, 
from, 358. 

Shark's Bay guano, 309, 328. 

Sheep, excrements of, 280, 281 ; solid 
excreta voided by, 280 ; urine voided 
by, 280. 

Sheep-dung, alkalies in, 226 ; com- 
position of, in dry state, 227 ; most 
valuable excrement, 227 ; nitrogen 
in, 226 ; phosphoric acid in, 226 ; 
water in, 226. 

Sheep-manure, 251 ; amount produced 
per day, 251 per year, 252 ; dry 
matter in, 252 ; mineral matter in, 
252 ; nitrogen in, 252. 

Sheep-urine, alkalies in, 230 ; com- 
position of, in dry state, 231 ; most 
valuable urine, 231 ; nitrogen in, 
230 ; phosphoric acid in, 230 ; water 
in, 230. 

Shoddy, 427; production of, 152, 
425 ; nitrogen in, 152, 427. 

Sicily, bones from, 360. 

Sidney Island guano, phosphoric acid 
in, 330. 

Siemens, Dr, experiments by, with 
light on plants, 38. 



Silica, in ash of plants, 55 ; in Chincha 
guano, 305 ; jelly, 169 ; necessary 
for plant-growth, 55. 

Silicates, 102 ; absorbed by cereals, 
494. 

Silicic acid fixed by soils, 58. 

Simon on humus in soil, 47. 

Slaked lime, 454. 

Slugs killed by lime, 461. 

Smut prevented by lime, 461. 

Soda, in ash of plants, 54 ; fixed by 
soils, 58 ; necessary for plant- 
growth, 55 ; nitrate of, 332 - 351 ; 
in salinas. 335 : replaces potash, 
466. 

Sodium chloride in Chincha Island 
guano, 305. 

Sodium phosphate in concretionary 
nodules, 328. 

Sodium sulphate in concretionary 
nodules, 328. 

Soil, 65-108 ; absorptive power of, for 
water, 67, 98 ; acids fixed by, 58- 
60 ; action of lime on, 453 ; am- 
monia absorbed by, 81 ; amount of 
soluble plant - food in, 100 ; arti- 
ficial, 54 ; barley, nitrates in, 158 ; 
bases fixed by, 58-60 ; best suited 
for nitrification, 192 ; biological 
properties of, 92-96 ; capacity for 
heat, 76-78 ; carbonic acid absorbed 
by, 81 ; chemical composition of, 
87 - 92, 101 - 107 ; colour of, 80 ; 
cropped, nitrates in, 157 ; denitri- 
fication in, 177 ; evaporation from, 
71, 72 ; farmyard manure, action of, 
on, 272 ; fertilising ingredients in, 
87 ; fertility of, 65-108 ; fineness of, 
69-70 ; gases in, 100 ; hygroscopic 
power of, 75-76, 99; improved by 
humus, 272 ; innueiice of farmyard 
manure on, 475 ; on nitrification, 
180 ; manures increase fertility of, 
474 ; nitrates in, amount of, 128- 
131 ; nitrifying organisms in, 179 ; 
distribution of, 179 ; nitrogen ab- 
sorbed by, 81, 82, 131 ; nitrogen 
accumulates, 133 ; nitrogen in, 
amount of, 120-128 ; nitrogen least 
abundant of manurial ingredients 
in, 270 ; nitrogen at various depths 
in, 156 ; oxygen absorbed by, 81 ; 
phosphoric acid in, 203 condition 
of, in, 203 occurrence of, in, 203 ; 



590 



INDEX. 



peat, 123 ; possesses power of fixing 
ammonia, 57 ; potash in, 215 con- 
dition of, in, 216 ; potential fertility 
of, 549 ; power of, for absorbing 
gases, 81 ; relation of, to plant- 
roots, 84 ; retention of plant-food 
by, 57 ; retentive power of, for 
water, 70-73 ; sewage purified by, 
435 ; shrinkage of, 74 ; variation in 
absorbing powers of, 82 ; varieties 
of, 67 ; virgin, 133 ; water in, most 
favourable amount of, 75 ; water- 
logged, 179 ; wheat, nitrates in, 157. 

Soluble phosphate, 386. 

Sombrero phosphate, 308, 328, 330, 
379 ; phosphoric acid in, 330. 

Somme phosphate, 378. 

Soot, 428 ; application of, rate of, 
429 ; crops suited by, 429 ; nitro- 
gen in, 428. 

South America, guano deposits in, 
327 ; meat-meal guano from, 324. 

Starbuck Island guano, 309, 328; 
phosphoric acid in, 330. 

Stassfurt salts, 214 ; potash in, 215, 
420. 

Stead and Eibsdale on formation of 
basic slag, 407. 

Stoeckhardt, on composition of solid 
excreta, 226 ; on composition of 
urine, 229. 

Storer, Professor, on composition of 
birds' dung, 331 ; on composition of 
leaves, 242 ; on fish - guano, 323 ; 
on nitrogen removed in milk, 147. 

Straw, composition of, 238 ; imports 
of, 153 ; as litter, 236, 248 ; mineral 
matter in, 238, 243 ; nitrogen in, 
237, 243 ; variation in composition 
of, 237. 

Subsoil, conditions favourable for 
nitrification in, 181. 

Suffolk coprolites, 374. 

Sugar-beet refuse, potash in, 219. 

Sulphate of alumina, a precipitant of 
sewage, 437. 

Sulphate of ammonia, 352-358 ; am- 
monia in, 355 ; application of, 356 ; 
composition of, 355; a concentrat- 
ed nitrogenous manure, 356 ; con- 
verted into nitrates, 356 ; from 
gas-works, 353 ; from iron-works, 
355 ; from shale-works, 354 ; manure 
for cereals, 356 ; most easily nitri- 



fiable manure, 191 ; production of, 
151, 358 ; properties of, 355 ; source 
of nitrogen, 149 ; sources of, 353, 
354, 358 ; sulphocyanate of ammonia 
in, 355. 

Sulphate of lime a fixer, 246. 

Sulphate of magnesia, an adulterant 
of guano, 319 ; as a fixer, 246. 

Sulphate of potash, application of, 
422 rate of, 423 ; compared with 
muriate, 421 ; sources of, 218, 420. 

Sulphuretted hydrogen from farm- 
yard manure, 258. 

Sulphuric acid, action of, on bones, 
382 on guano, 311 on tricalcic 
phosphate, 398 ; in ash of plants, 
54 ; as a fixer, 245, 285 ; necessary 
for plant -growth, 55; superphos- 
phate manufactured with, 384, 388. 

Superphosphate, 382-400; action of, 
392-395 sometimes unfavourable, 
395 ; application of, 395 rate of, 
397 ; composition of, 391 ; discovery 
of, 382 ; hastens early growth, 394 ; 
high -class, 392 ; low -class, 392 ; 
manufacture of, 383 - 385 phos- 
phates suitable for, 384 ; medium- 
class, 391 ; production of, 382 ; 
reversion in, 389, 399, 400 causes 
of, 389, 390 ; reverted in soil, 392. 

Surprise Island guano, 328. 

Swan Island guano, 328. 

Swedes, fertilising ingredients remov- 
ed from soil by, 485 ; manurial con- 
stituents in, 282 ; manuring of, 514. 

Swine-dung, alkalies in, 226 ; com- 
position of, 227 ; nitrogen in, 226 ; 
phosphoric acid in, 226 ; water in, 
226. 

Swine-urine, alkalies in, 230 ; com- 
position of, 231 ; nitrogen in, 230 ; 
phosphoric acid in, 230; water in, 
230. 

Sydney Island guano, 309. 

Syenite, 106 ; phosphoric acid in, 202, 

Sylvin, potash in, 220. 
Symbiosis, 44. 

Tamarugal, Pampa de, nitrate deposits 
in, 340. 

Tarapaca, nitrate deposits in, 340. 

Temperature necessary for nitrifica- 
tion, 52, 175. 



INDEX. 



591 



Tetracalcic phosphate, 387 ; occur- 
rence of, 387, 405 ; solubility of, 
387. 

Thaer on application of farmyard 
manure, 275. 

Thiocyanates, nitrification in, 182. 

Thomas - Gilchrist process of steel- 
smelting, 402. 

Thomas-slag. See Basic slag. 

Tillage increases number of plants, 86. 

Timor Island guano, 309. 

Tobacco, potash in, 217. 

Torrefied horn, 426. 

Torrefied leather, 428. 

Tortola guano, 309. 

Trachyte, phosphoric acid in, 202, 211. 

Transpiration, by elm-tree, 71 ; by 
oak-tree, 71. 

Trees, as pumping-engines, 76 ; water 
transpired by, 71. 

Tricalcic phosphate, 386, 398. 

Tubercles on roots of plants, 44. 

Tull, Jethro, theory of, on plant- 
growth, 9-11, 69, 109. 

Turkey, dung produced by, 331. 

Turnips, fertilising ingredients re- 
moved from soil by, 485 ; manurial 
constituents in, 282 ; manuring of, 
510, 511, 513 - 517 ; Kothamsted 
experiments on growth of, 568. 

Twigs, potash in, 217. 

Tyrosin, assimilated by plants, 47. 

Ulmates in farmyard manure, 259. 
Ulmic acid, in farmyard manure, 258 ; 

in humus, 47. 
Ulmin in humus, 47. 
Uncovered farmyard manure, 263, 

289. 
Unexhausted manures, valuation of, 

549-552, 558. 
Unit value of manurial ingredients, 

544. 
Units for determining commercial 

value of manures, 554. 
Urate of ammonium in Chincha Is- 
land guano, 305. 
Urea, assimilated by plants, 46 ; in 

farmyard manure, 257 ; nitrification 

in, 182. 
Uric acid, experiments with, 46 ; in 

Chincha Island guano, 305. 
Urine, 228 ; amount voided, 291 ; 

composition of, varies, 228 ; con- 



tains digested manurial ingredients, 
228, 232 ; devoid of phosphoric acid, 
205 ; and dung, composition of, 
234 ; influence of food on, 229 ; 
nitrification in, 197 ; nitrogen in, 
292 ; potash in, 292 ; voided by 
cows, 280 ; voided by oxen, 280 ; 
voided by pigs, 281 ; voided by 
sheep, 280. 
Uruguay, meat-meal guano from, 324. 

Valuation of manures, 539-559. 

Vegetation, desirable to have soil cov- 
ered with, 194. 

Venezuela, guano deposits at, 327. 

Ville, Georges, on assimilation of 
ammonia, 50 ; theory of, on source 
of plant-nitrogen, 41. 

Vine, potash removed by, 216. 

Virgin soils, 133. 

Voelcker, Dr, analysis of apatite, 210 
of farmyard manure, 259 ; on 
action of superphosphate, 395 ; on 
fresh and rotted dung, 261, 286 ; on 
guano, 316 ; on salt as a manure, 
473. 

Voss, Hermann, on manures used, 
152. 

Wagner, Professor, on, application of 
basic slag, 416 ; assimilation of 
organic nitrogen, 46 ; experiments 
with basic slag, 408-413 ; fineness 
of basic slag, 409 ; manures, 412 ; 
relative manurial value of nitrogen 
compounds, 556 ; solubility of basic 
slag, 408. 

Wallace, Dr, on sewage purification, 
436. 

Walruses, guano from, 297. 

Warington, E., on ammonia in rain, 
49 ; on appearance of nitrous organ- 
isms, 168 ; on conditions favourable 
for nitrification, 181 ; experiments 
on rate of nitrification, 186 ; on 
composition of farmyard manure, 
260 ; on manufacture of superphos- 
phate, 383 ; on manurial constitu- 
ents of foods, 282 ; on nitrification 
in alkaline solutions, 197 ; on ni- 
trogen in excrements, 233 ; on ni- 
trogen in soil, 122 ; on potash in 
wool, 227 ; researches of, on nitrifica- 
tion, 35, 52, 166-168, 180, 186. 



592 



INDEX. 



Water, absorbed by plants, 73 ; 
amount of, transpired by plant- 
leaves, 56 ; an adulterant of guano, 
319 ; a carrier of plant-food, 55 ; 
in cow-dung, 226 cow-urine, 230 ; 
from decomposition of farmyard 
manure, 257 ; in horse-dung, 226 
horse - urine, 230 ; necessary for 
plant, 67 ; in pig-dung, 226 pig- 
urine, 230 sheep - dung, 226 
sheep - urine, 230 ; transpired by 
elm-tree, 71 oak-tree, 71. 

Water-culture, 54. 

Water-logged soils, 179. 

Waterloo, bones from, 360. 

Way, Thomas, on retention of plant- 
food by soil, 57, 59 ; on sewage, 437. 

West Indies, guano from, 298. 

Whales, guano from, 322. 

Wheat, fertilising ingredients removed 
from soil by, 485 ; Flitcham experi- 
ments on, 500 ; manurial constitu- 
ents in, 282 ; manuring of, 499-501 ; 
nitrogen removed in crop of, 145 ; 
requires nitrogenous manures, 499 ; 
Rothamsted experiments on, 500, 
562-565 ; a source of nitrogen, 153. 

Wheat-soils, nitrates in, 157. 

Wheat-straw, analysis of stable man- 
ure made from, 283 ; composition 
of, 238 ; manurial constituents in, 
282. 



White clover, growth of, promoted by 
lime, 451. 

Wiegmann on ash constituents of 
plants, 53. 

Wilfarth on nitrogen in plants, 44. 

Wilting, 73. 

Winogradsky, on nitrification, 52, 
167, 169, 197 : on organisms in 
soil, 94. 

Wolff on, analysis of manure - heap 
draiiiings, 290 ; composition of 
fresh and rotten dung, 288 ; assimi- 
lation of organic nitrogen by plants, 
47 ; relative manurial value of 
manurial compounds, 556 ; urine, 
232. 

Wood-ashes as potash manure, 218, 
419. 

Woodhouse, researches of, on nitrogen 
in plants, 41. 

Wool, capable of nitrification, 182 ; 
potash in, 217. 

Wool-waste, 427 ; nitrogen in, 427. 

Wooluey, on organisms in soils, 93, 
95 ; on water in soils, 75. 

Wrightson, Professor, on application 
of basic slag, 414. 

Yeast, 94. 

Yorkshire, bones first used in, 359. 

Zeolites, potash in, 220. 



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