Familiar Letters on Chemistry


The Letters contained in this little Volume embrace some of the most important points of the science of Chemistry, in their application to Natural Philosophy, Physiology, Agriculture, and Commerce. Some of them treat of subjects which have already been, or will hereafter be, more fully discussed in my larger works. They were intended to be mere sketches, and were written for the especial purpose of exciting the attention of governments, and an enlightened public, to the necessity of establishing Schools of Chemistry, and of promoting, by every means, the study of a science so intimately connected with the arts, pursuits, and social well-being of modern civilised nations.

For my own part I do not scruple to avow the conviction, that ere long, a knowledge of the principal truths of Chemistry will be expected in every educated man, and that it will be as necessary to the Statesman, the Political Economist, and the Practical Agriculturist, as it is already indispensable to the Physician, and the Manufacturer.

In Germany, such of these Letters as have been already published, have not failed to produce some of the results anticipated. New professorships have been established in the Universities of Goettingen and Wuertzburg, for the express purpose of facilitating the application of chemical truths to the practical arts of life, and of following up the new line of investigation and research—the bearing of Chemistry upon Physiology, Medicine, and Agriculture,—which may be said to be only just begun.

My friend, Dr. Ernest Dieffenbach, one of my first pupils, who is well acquainted with all the branches of Chemistry, Physics, Natural History, and Medicine, suggested to me that a collection of these Letters would be acceptable to the English public, which has so favourably received my former works.

I readily acquiesced in the publication of an English edition, and undertook to write a few additional Letters, which should embrace some conclusions I have arrived at, in my recent investigations, in connection with the application of chemical science to the physiology of plants and agriculture.

My esteemed friend, Dr. Gardner, has had the kindness to revise the manuscript and the proof sheets for publication, for which I cannot refrain expressing my best thanks.

It only remains for me to add a hope, that this little offering may serve to make new friends to our beautiful and useful science, and be a remembrancer to those old friends who have, for many years past, taken a lively interest in all my labours.

Giessen, Aug. 1843.



The Subject proposed. Materials employed for Chemical Apparatus:— GLASS—CAOUTCHOUC—CORK—PLATINUM. THE BALANCE. The "Elements" of the Ancients, represent the forms of matter. Lavoisier and his successors. Study of the materials composing the Earth. Synthetic production of Minerals—LAPIS LAZULI. Organic Chemistry.


Changes of Form which every kind of Matter undergoes. Conversion of Gases into Liquids and Solids. Carbonic Acid—its curious properties in a solid state. Condensation of Gases by porous bodies. By Spongy Platinum. Importance of this property in Nature.


The Manufacture of Soda from Culinary Salt; its importance in the Arts and in Commerce. Glass—Soap—Sulphuric Acid. Silver Refining. Bleaching. TRADE IN SULPHUR.


Connection of Theory with Practice. Employment of MAGNETISM as a moving power—its impracticability. Relation of Coals and Zinc as economic sources of Force. Manufacture of Beet-root Sugar—its impolicy. Gas for illumination.


ISOMERISM, or identity of composition in bodies with different chemical and physical properties. CRYSTALLISATION. AMORPHISM. ISOMORPHISM, or similarity of properties in bodies totally different in composition.


ALLIANCE OF CHEMISTRY WITH PHYSIOLOGY. Division of Food into nourishment, and materials for combustion. Effects of Atmospheric Oxygen. Balance of CARBON and OXYGEN.


ANIMAL HEAT, its laws and influence on the Animal Functions. Loss and SUPPLY. Influence of Climate. Fuel of Animal Heat. Agency of Oxygen in Disease. Respiration.


ALIMENTS. Constituents of the Blood. Fibrine, Albumen. Inorganic Substances. Isomerism of Fibrine, Albumen, and elements of nutrition. Relation of animal and vegetable organisms.


Growth of Animals. Uses of Butter and Milk. Metamorphoses of Tissues. Food of Carnivora, and of the Horse.


Application of the preceding facts to Man. Division of human Food. Uses of Gelatine.


CIRCULATION OF MATTER IN THE ANIMAL AND VEGETABLE KINGDOMS. The Ocean. AGRICULTURE. RESTITUTION OF AN EQUILIBRIUM IN THE SOIL. Causes of the exhaustion of Land. Virginia. England. Relief gained by importation of bones. Empirical farming unsatisfactory. Necessity for scientific principles. Influence of the atmosphere. Of Saline and Earthy matters of the soil.


SCIENCE AND ART OF AGRICULTURE. NECESSITY OF CHEMISTRY. Rationale of agricultural processes. Washing for gold.


ILLUSTRATION OF THE NECESSITY OF CHEMISTRY TO ADVANCE AND PERFECT AGRICULTURE. Manner in which FALLOW ameliorates the soil. Uses of Lime. Effects of Burning. Of Marl.


NATURE AND EFFECTS OF MANURES. Animal bodies subject to constant waste. Parts separating—exuviae—waste vegetable matters—together contain all the elements of the soil and of food. Various value of excrements of different animals as manure.


SOURCE OF THE CARBON AND NITROGEN OF PLANTS. Produce of Carbon in Forests and Meadows supplied only with mineral aliments prove it to be from the atmosphere. Relations between Mineral constituents, and Carbon and Nitrogen. Effects of the Carbonic Acid and Ammonia of Manures. Necessity of inorganic constituents to the formation of aliments, of blood, and therefore of nutrition. NECESSITY OF INQUIRIES by ANALYSIS to advance AGRICULTURE.


RESULTS OF THE AUTHOR'S LATEST INQUIRIES. Superlative importance of the PHOSPHATES OF LIME and ALKALIES to the cultivation of the CEREALIA. Sources of a SUPPLY of these MATERIALS.


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