A History of Chemistry (Moore)

A History of Chemistry (1918) is a work by American chemist Forris Jewett (F.J.) Moore, Ph.D., who taught chemistry at M.I.T. from 1894 until 1925, when he retired from active teaching due to poor health.

Quotes

Preface

This volume is the outgrowth of a series of talks which the author had for several years given to his students at the Institute of Technology... The lectures have dealt in a direct informal way with the fundamental ideas of the science: their origin, their philosophical basis, the critical periods in their development, and the personalities of the great men whose efforts have contributed to that development.

[T]he person addressed is the more mature student of chemistry, though it is believed that few portions of the book will present serious difficulties to the general reader.

The aim has been to emphasize only those facts and influences which have contributed to make the science what it is today... [T]he claim of a topic for consideration has been not its practical but its historical importance... [i.e.,] did it contribute a new fundamental idea.

Little attention has been paid to questions of priority. A great discovery is usually preceded by a multitude of earlier observations, the sum total of which may even include all the fundamental facts involved. ...[F]rom the historical standpoint the discoverer of a great truth is usually the one through whose efforts it first becomes available to the [human] race.

The value of the historical method for studying every department of human thought is now so universally recognized that it requires no emphasis, but... by observing the errors and misunderstandings of the past, we learn to avoid errors in our own thinking; by acquaintance with the way in which great men have solved problems, we are assisted in solving problems of our own; by observing the different aspects presented by the same facts in the light of successive theories, we acquire an insight obtainable in no other way into the nature, limitations and proper function of all theories.

[A]s we study how man's knowledge of nature has broadened and deepened with the years, we acquire a better understanding of the trend of thought in our own times, and of the exact bearing of each new discovery upon the old but ever recurring problems of the science.

At no period has the development of chemistry been more rapid or more interesting than it is today, and the author indulges the hope that even this brief sketch of its history may assist the reader to follow that development with a fuller appreciation of its significance, for, after all, we study the past that we may understand the present and judge wisely of the future.

Ch. V. The Later Phlogistians—The Discovery of Oxygen

Black on Magnesia Alba

With Joseph Black (1728-1799) we come to the eminent group of distinguished chemists whose work contributed so largely to the overthrow of the phlogiston theory... [T]hey themselves almost without exception remained blind to this, its most important significance.

Black was long professor in Glasgow, and made some important discoveries in physics, developing independently the idea of specific heat and of latent heat, though his work was not formally published.

He is best remembered... for his work on magnesia alba which he presented for the doctor's degree in 1754. In this investigation he took up the study of what we now call magnesium carbonate as a new substance... we may sum up Black's results in a series of propositions:
I. Magnesia alba when strongly heated loses about half its weight and yields a new substance magnesia usta (magnesium oxide)
II. With vitriolic acid magnesia alba yields epsom salt (magnesium sulphate) with effervescence.
III. Magnesia usta when similarly treated yields epsom salt without effervescence.
IV. In a solution of epsom salt, mild alkali (potassium carbonate) precipitates magnesia alba and the solution on evaporation yields vitriolated tartar (potassium sulphate).
V. Mild alkali effervesces with acids while caustic does not.
VI. Mild alkali is made caustic by addition of magnesia usta.

[I]t is... easy to see what a handicap upon the chemists of that time was the use of a nomenclature necessarily incapable of expressing chemical relationships, and how impossible it then was to know whether all substances in a reaction were accounted for or not. Nevertheless, Black interpreted his results with perfect accuracy.

From II and III he concluded that the difference between magnesia alba and magnesia usta was the gas ("fixed air") liberated from the former by acids, and that it was the expulsion of the same gas which accounted for the loss of weight when magnesia alba was heated (I).

II and IV showed that magnesia alba could be regenerated from magnesia usta by the aid of mild alkali, hence the latter must contain fixed air which it surrenders in the reaction. This is further confirmed by V which shows that mild alkali differs from caustic by its content of fixed air.

VI completes the caustifying of the alkali by the action of magnesia.

Black saw at once that these reactions were analogous to those involved in the ancient method of preparing caustic alkali from quicklime. He accordingly repeated his experiments using limestone instead of magnesia alba and so reached the correct conclusion that the 'burning' of lime consists essentially in the expulsion of fixed air.

Such a result was utterly opposed to [previous] explanations... [i.e.,] when lime was heated in the kiln phlogiston entered into it making it fiery or caustic. Later when the quicklime was treated with mild alkali another transfer of phlogiston occurred and the latter became caustic in its turn.

[I]n later years, when Lavoisier had once shown the way, Black was among the first to adopt the new views.

Cavendish

[A]lthough in middle life he inherited a fortune which made him one of the richest men in England, this had no influence upon his regular and frugal habits.

[H]is work was done with little thought of fame, and much of the best of it remained entirely unknown till long after his death.

Cavendish was the first to make a thorough study of hydrogen and he gave it the name of "inflammable air" in a paper published in 1766. The evolution of a combustible gas when a metal is dissolved in acids was observed much earlier. We are reasonably sure that it was known to Paracelsus and Van Helmont, and we know that it was isolated by Boyle.

Cavendish identified hydrogen with phlogiston, and this was entirely in the spirit of current views, for if a metal is a compound of a base with phlogiston then when the base unites with an acid to form a salt phlogiston must escape.

About 1783, after the discovery of oxygen. Cavendish combined this gas with hydrogen by means of the electric spark, and so established the composition of water.

In 1785... he noticed that oxygen and nitrogen when sparked... over water yielded nitric acid... He always found... a small inert residue whose volume... he estimated at about 1/120 of the whole. ...in spite of this valuable clue ...argon and the other rare gases of the atmosphere remained undiscovered for more than a hundred years.

Cavendish... accounted for his results in terms of the phlogiston theory... on the assumption of Priestley that oxygen was "dephlogisticated air," that portion... which unites with phlogiston on combustion.

He was not ignorant of the work of Lavoisier, and acknowledged frankly that the latter's views would explain the results of his experiments "nearly as well," but after weighing both opinions he clung to the old for what now seems a curious reason. He writes:
"There is one circumstance also, which though it may appear to many not to have much force, I own has some weight with me; it is, that as plants seem to draw their nourishment almost entirely from water and fixed and phlogisticated air, and are restored back to those substances by burning, it seems reasonable to conclude, that notwithstanding their infinite variety they consist almost entirely of various combinations of water and fixed and phlogisticated air, united according to one of these opinions to phlogiston, and deprived according to the other of dephlogisticated air; so that, according to the latter opinion, the substance of a plant is less compounded than a mixture of those bodies into which it is resolved by burning; and it is more reasonable to look for great variety in the more compound than in the more simple substance."

About A History of Chemistry

F. J. Moore was born at Pittsfield, Mass., June 9, 1867. ...He ...went to the University of Heidelberg, where he studied with Victor Meyer and with Gatterman ...and was awarded the degree of doctor of philosophy in 1893. ...In ... 1894 he came to the Massachusetts Institute of Technology ...The condition of his health caused him to retire from active teaching in 1925 ...All American students of the history of chemistry are familiar with Moore's book on the subject. Many owe to it their first interest in the history of their science. ...He published "Outlines of Organic Chemistry (1910), "Experiments in Organic Chemistry" (1911), and "A History of Chemistry (1918). The last book shows the character of the man—widely read, witty, and lucid. It is entertainingly written and can be recommended to chemist and non-chemist alike. The writer has found it excellent medicine for the student who thinks that organic chemistry is difficult, for it gives him an interest which removes difficulties and makes intricacies appealing. As an undergraduate at Amherst, F.J. Moore was interested in chemistry and in philosophy... Although he decided to pursue the chemistry, his "History of Chemistry" makes it clear that he never abandoned the philosophy.
- Tenney L. Davis, "F.J. Moore—Historian of Chemistry" The Journal of Industrial and Engineering Chemistry (September 1, 1927) Vol. 19, No. 9, p. 1066.

External links

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- A History of Chemistry (1918) by F. J. Moore