1844.] 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



71 



restoration of the celebrated Pompeian mosaic, supposed to be a battle of 

 Alexander and Darius. 



The king of Prussia has restored the castle of Stolzenfels, on the Rhine. 



St. Paul's church, at Auckland, in New Zealand, is completed, and a small 

 church is to be erected at Windsor. 



The lightning conductors for the Royal Exchange have been arranged 

 und^T the direction of Mr. C. Walker, the able secrerary of the Lonilun 

 Ulcctrical Society, and author of the continuation of Dr. Lardner's work on 

 electricity. 



The Exposition of Arts and Manufactures at Berlin, was opened on the 

 2-ttb ult. It belongs to the Trade Union, a society established four and 

 twenty years, reckoning 972 subscriliers, and now largely endowed. 



The Cologne and Bonn railway is completed. This opens the communica- 

 tion with Antwerp and Ostend. 



The General Steam Navigation Company have oftered to establish a daily 

 communication between Brighton and Diepjje, if the authoritiei of Dieppe 

 will go to a little expence in dredging the channel. 



The works in Trafalgar Square are, with the exception of the Nelson 

 monument, fast coming to a com]iletion. The stone is all down, the con- 

 crete is commenced as well as the bitumen of the Bastenne Company, and 

 when the weather will admit the completion of the concreting, the bitumen 

 paving, which is to cover the whole area around the fountains, will be finished. 

 This will be the largest space so covered in this country, and will form a new 

 feature in our public, as well as private walks. It appears by the works pro- 

 ceeding during the late frost, that there is no fear of any injurious effect from 

 this description of material being laid in winter as well as lummer. We hope 

 to be able very shortly to give a plan of the square, describing the terrace 

 and fountains, and also showing how the different stones, bitumen and 

 cement have been used. 



The South Eastern Railway wai opened on Tuesday throughout to Dover. 



AGRICULTURAL CHEMISTRY. 



A Course of ten Lecturer by Professor Bramde, F.R.S., tit the Royal Institution, 



deiwered January 27th. (Specially reported for tbit Journal,) 



Lecture I, 



The Professor commenced by observing that he entered upon this course 

 of U'Clures with great diifidcnce and anxiety, and at the same time with a 

 great deal of pleasure — be was aware that the subject of Agricultural Chemis- 

 try is one that is attracting a great share of attention, and that it is in the 

 hanils of eminent chemists and skilful practical agriculturists i he was also 

 aware that a great deal has been held out as to what chemistry may do, and 

 can do, and will do in this very important subject ; upon this subject he 

 would endeavour to bring before his bearers, in plain and intelligent language, 

 the main subject which the agricultural chemist ought to attend to— in fact, 

 the practical agriculturist ; because hu did not hesitate to say that every 

 farmer — every practical agriculturist, ought to be acquainted with at least 

 the principles of agricultural chemistry. 



He entered upon the subject with pleasure, because he was appointed by Sir 

 Humphrey Davy, many years ago. to deliver a course of lectures to the then 

 existing board of agriculture, at the time that he retired from the oRice of 

 Professor of Agricultural Chemistry to that body. He bad still the notes 

 and memoranda which Sir Humphrey gave him upon that occasion, and be 

 looked back to them with much pleasure as containing the germs of almost 

 everything that has been done in agricultural chemistry since that period. 

 The business of the practical farmer is in fact very simple. It is, to raise from 

 a given extent of land the largest quantity of the most valuable produce, and 

 to do that in the most economical way, both as regards time and money, 

 and further in such a manner as permanently to impoverish the soil as little 

 as possible. It is his business tu show what aids are derivable from chemistry 

 in reference to the accomplishment of this highly important object. The sub- 

 ject of agricultural chemistry, if we consider it as bearing upon the iminove- 

 ment of land, in its practical, rather than its theoretical, bearing— has now 

 of course become a matter of the greatest importance. Our population in- 

 creases rapidly upon our territory, and unless means be found to increase 

 the produce of the land, emigration or other didiculiies must occur to a great 

 extent ; and he thought it was perfectly obvious that a great deal.of cultivateil 

 land in this country may be brought into a higher state of cultivation, and 

 that a great deal of uncultivated land may be brought into a state of practi- 

 cal cultivation. There is something very extraordinary— though being every 

 day before our eyes, we do not regard it as such, in the growth of a seed.— 

 If we take for instance a seed of turnip, or rape, or wheat, we find that in the 

 course of a certain time, and under particular circumstances, it produces a plant 

 or a tree. Nothing, fur example, can be more remarkable than that in the 

 course of a few weeks, a small seed becomes a perfect plant ; nothing can be 

 more astonishing, if we look at it in all its details, than that a small acorn 

 in a few years grows into the stately and majestic oak. The question we 

 have to examine into is, '• How is all this to be elfected ?" and to this end it 

 is obvious that we should consider the changes in the seed itself, which is a 

 matter of great importance. We find when toe .'ejd is placed in a congenia 



soil, that it soon expands, and then the germ begins to grow, it puts forth a 

 rootlet, and after a time it makes its way downwards, and the stem makes 

 its way upwards. During these changes there are very curious chemical 

 alterations going on in the constitution of the seed itself, to which he will 

 hereafter call your attention. Here we find that as soon as the young plant 

 has taken such nourishment as it could get from the seed, it becomes de- 

 pendent upon the soil which contains the root, and upon the atmosphere to 

 which the branches are exposed. From the soil there is a considerable quan- 

 tity of matter taken, and the leaves also imbibe a considerable quantity from 

 the air. These agents therefore we have to create. 



1st. As to the soil— we have to consider it as the mechanical support of 

 the plant, and in this respect the texture of the soil is a matter of importance. 

 Then we find that it derives nourishment from the soil in three ways: — 1st. 

 we have to examine the inorganic constituents which the soil gives to the 

 plant — and if «e take the stem, or the leaves, or any other portion of a plant, 

 it will be found that it contains a quantity of saline, or earthy, or other par- 

 ticles which we call inorganic matter, which it cannot take from the air, and 

 which therefore it must take from the soil. 2nd. There is also a quantity of 

 organic matter taken up from the soil — and 3rd. It will be found to be under- 

 going changes through the influence of the air affecting both itself and the 

 atmosphere. 



T'hese are some of the principles to which the learned Professor observed 

 that he should have to revert in reference to the soil.— Next, in reference to 

 the state of the air. Having determined what are the elements of the plant, 

 and which it cannot get from the soil, we must search the air, and having 

 ascertained its constituents, ascertain how far they contribute to the growth 

 of the plant. It is extraordinary, but nevertheless true with regard to plants, 

 that the nourishment they derive from the soil is very insignificant compared 

 with what it obtains from the air. Take an oak for instance, in the course of 

 a certain number of years it will contain perhaps several tons of wood. Now 

 it is quite clear that the oak must have derived this either from the soil or the 

 atmosphere. Has it impoverished the soil';' — taken anything from it? — Cer- 

 tainly not J on the contrary, we find that the soil so far from having imparted 

 organic substances, has in fact gained them, and there is an increase of the 

 organic matter in the soil, arising from the shedding of the leaves, or the 

 accidental fall of a branch, &c. — It is obvious then that this great acquisition 

 of mattir must have come from the atmosphere. — The atmosphere is a con- 

 tinual source of food to the plant ; and as the plant cannot go about like an 

 animal to search for its food, the atmosphere is continually wafting about 

 the plant, and no sooner is the nourishment abstracted from one portion of 

 atmusphere, than a fresh portion brings fresh nourishment which the plant 

 greedily devours. 



Without the soil it is true the plant could not get those inorganic consti- 

 tuents to which he has referred, if, for instance, we find in a plant lime, a 

 phosphoric acid, it is clear they must come from the soil ; but the carbon, 

 hydrogen, and oxygen come from the atmosphere — not entirely, but princi- 

 pally — and in such quantities as not only enable the tree to grow, but, as he 

 said before, by the shedding of the leaves, &c. to enrich the soil : and wc do 

 find actually that by the growth uf trees the soil is considerably enriched, 

 as far as organic matter is involved. 



Having then examined how far the soil and the air are concerned in these 

 matters.wearenext to look at what will be brought before you as the ultimate 

 and proximate elements of a vegetable. By ultimate elements, we mean 

 those actual elementary substances which cannot be decomposed : by proxi- 

 mate elements, their secondary arrangements and results — sugar, starch, 

 gum, &c., and the approximate elements of a vegetable. 



Then there is another subject i must bring before you, viz., ** \\"hat are the 

 functions ol the different class of plants?" And lastly, bow far mechanical 

 and chemical expedients may be resorted to, to render barren soils fertile, and 

 fertile soils continuously so. We shall find that the roots and the leaves of 

 plants atlect peculiar functions — tliat the roots take up certain matiers from 

 the soil, and that the leaves and all the green parts of the plant are ener- 

 getically employed in taking up an immense quantity of nourishment from 

 the atmosphere, We are all aware of the beautiful provision by which the 

 vegetable is made to take up, as it were, the refuse of animals. Wi' may say 

 that we are deteriorating the air as far as we ourselves are concerned, but 

 we are impunng it fur the growth of plants. We are like organs engaged 

 in infusing into the air what is pio|>er for plants, which they take up, thereby 

 again rendering the atmosphere fit for our use. 



Under the head of the mechanical and chemical expedients to be resorted 

 to for rendering barren soils fertile, and fertile soils continuously, so we shall 

 of course come to a number of facts connected with the influence of ma- 

 nures and the dilferentoperationsof tillage. Looking at soils, in the first place 

 they must of course originate in the action of the air, water, heat and light, 

 or of those agents commonly designated under the term of " the weather " 

 upon the earth; and as the dilfecent rucks or strata which form the crust 

 of the earth, are some exposed in one place and some in another, giving 

 thereby a dilierent constitution to the soil, we see the important bearing of 

 geological science upon agriculture. 



