Philosophy Of Science

"So great a result is not the work of one day or the conquest of a revolution; it is the result of slow and continued progress. But if we... carry our ideas back to the starting-point, we must avow that the progress is immense. Compared with the science of that time, the science of the present day appears to us not only enlarged, but transformed and regenerated."

"Is it complete, as regards its doctrines; and are the new paths... made altogether plain? We do not think so. But the greatness of the advance permits us to affirm that the roads are good. We may then halt for a moment, and, casting our eyes over the distance already traversed, mark with certainty the point at which we have arrived."

"Free use has been made of all the chief authorities; the historical works of Kopp, Berthelot, Hoefer, Thomson, Ernst v. Meyer, Ladenburg, Rodwell, Muir, Wurtz, Hartmann, Gmelin, Karmarsch, and Siebert, besides the original works of nearly all the chemists mentioned for the past century and a half, have been consulted."

"The ovum from which chemistry has been slowly evolved seems to have been sorcery and magic."

"It is therefore the occult or hidden science, the black art."

"Two difficulties meet one in studying the early history of the science. One is... mysticism... and the other is the custom among the early writers of ascribing their discoveries, books, etc., to fabulous names or ancient heroes and gods. This latter had two objects, the first being to shield the true author in time of persecution, and the second to gain a certain amount of credit and reputation... by the use of the names of such celebrities as Moses, Solomon, Alexander, or Cleopatra. This tendency is especially noticeable among the writers of the Middle Ages, and also the early Greek authors, and is not peculiar to authors of alchemical treatises."

"The reason generally assigned for this absence of early records is that burned all writings of the Egyptians bearing upon alchemy, because, as he said, these taught the art of making gold and silver; and, by destroying them, he took away from the Egyptians the power of enriching themselves and rebelling against the Romans."

"[T]he Chinese... had... knowledge of metals, alloys, colors, and salts for a long time, and that they manufactured gun powder and porcelain before they were known in Europe."

"[T]here is a similarity easily detected between the hieroglyphics and the alchemical signs. The phraseology in the early treatises is similar to that in the priestly writings."

"[N]ote the important part played by the number four with the alchemists as well as with the Egyptian priests. There are the four bases or elements, the tetrasomy of ; the four zones, four funeral deities, four cardinal points, four winds, four colors, etc."

"Ostanes, the Mede, was one of the celebrated early alchemists. Several writers have recorded for us the existence of a book called The Book of the Divine Prescriptions, which seems to have been the most famous writing of these Persian sages."

"The belief in some wonderful connection between planets and metals is due to these ns. The signs of the heavenly bodies became the symbols for the metals. These planets influenced a supposed growth of the metals, and were esteemed all-powerful in regulating human life and fate. Many of these notions are to be attributed to the Alexandrian epoch."

"In 1774 he thought he had obtained ... in 1775 he saw the gas as dephlogisticated air... If we refuse the palm to Priestley, we cannot award it to Lavoisier for the work of 1775... Lavoisier insisted that oxygen was an atomic "principle of acidity"... formed only when that "principle" united with "caloric"... Ignoring Scheele, we can safely say that oxygen had not been discovered before 1774, and we would probably say that it had been discovered by 1777 or shortly thereafter. But... any attempt to date the discovery must inevitably be arbitrary because discovering a new sort of phenomenon is necessarily a complex event, one which involves recognizing both that something is and what it is."

"We avoid the gravest difficulties when, giving up the attempt to frame hypotheses concerning the constitution of matter, we pursue statistical inquiries as a branch of rational mechanics."

"In writing a textbook of general chemistry, Mendeleev devoted separate chapters to families of elements with similar properties, including the alkali metals, the alkaline earth metals, and the halogens. Reflecting on the properties of these and other elements, he proposed in 1869 a primitive version of today's periodic table. Indeed, he predicted detailed properties for three such elements (scandium, gallium, and germanium). By 1886 all of these elements had been discovered and found to have properties very similar to those he had predicted."

"It was in consequence of living for some time in the neighbourhood of a public brewery, a little after Midsummer in 1767, that I was induced to make experiments on fixed air..."

"We must not forget that when was discovered no one knew that it would prove useful in hospitals. The work was one of pure science. And this is a proof that scientific work must not be considered from the point of view of the direct usefulness of it. It must be done for itself, for the beauty of science, and then there is always the chance that a scientific discovery may become like the radium a benefit for humanity."

"By convention (νόμῳ) sweet is sweet, by convention bitter is bitter, by convention hot is hot, by convention cold is cold, by convention color is color. But in reality there are atoms and the void. That is, the objects of sense are supposed to be real and it is customary to regard them as such, but in truth they are not. Only the atoms and the void are real."

"Alkimia Speculativa... treats of the generation of things from their elements, and of all inanimate things—as of the elements and liquids (humores) simple and compound; common stones, gems, and marbles; gold, and other metals; sulphur, salts, pigments, lapis lazuli, minium, and other colours; oils, bitumen, and very many other things—of which we find nothing in the books of Aristotle; nor are the natural philosophers or any of the Latins acquainted with these things. And being ignorant of them, they can know nothing of what follows in physics, that is, of the generation of animate things—as vegetables, animals, and man—because knowing not what is prior, they must remain ignorant of what is posterior. For the generation of men, and of brutes, and of plants, is from elemental and liquid substances, and is of like manner with the generation of inanimate things. Wherefore, through ignorance of this science, neither can natural philosophy... be known, nor the theory, and therefore neither the practice, of medicine; not merely because natural philosophy and theoretical medicine are necessary for the practice, but because all simple medicines are derived from inanimate things by this science."

"Even though Mendeleev always denied that electrons exist, they later turned out to be vital for ordering the elements in his table."

"Dimitri was writing a textbook and wanted to organize the elements properly. So he wrote each element onto its own card to help him sort them out. Dimitri enjoyed playing cards, especially patience, and one evening he dosed off while working. He had a dream in which each of the cards lined up in rows, just like a game of patience. When he woke, he realized that he should put the elements in order of atomic mass."

"Berthollet's conclusion that chlorine is oxymuriatic acid was universally accepted until Gay-Lussac and Thénard in 1809 endeavoured to decompose the gas and failed. They concluded that it contained water because it yielded water when passed over litharge. Their researches read to the Institute in 1809 led Davy to investigate muriatic acid (hydrochloric acid) gas, which in 1808 he had shown to be decomposed by potassium, with evolution of hydrogen. In 1810 he proved that chlorine is an element, and that muriatic acid gas is a compound of chlorine and hydrogen. He thus overturned the oxygen-acid theory, and demonstrated that muriates are compounds of metals with chlorine. He pointed to the fact that some acids, such as sulphuretted hydrogen, contain no oxygen, and argued that muriatic acid gas was one of these, chlorine in it taking the place of oxygen. ...The conclusions of Davy were at first doubted, but when iodine and bromine were also discovered, Gay-Lussac and his followers adopted Davy's views. The latter worked out fluorine, and proved that hydrofluoric acid (HF) contains no oxygen. Berzelius also opposed Davy until the discovery of iodine, but embraced the latter's opinion in 1820."

"Davy held that if the battery is strong enough any compound may be decomposed, and that chemical affinity is merely a form of electric attraction. He vigorously put his theory into practice..."

"[T]he first period [prehistory to 500 B.C.] into which the history of chemistry naturally divides itself is that during which a number of chemical facts were known, but not understood or explained. These facts were not correlated, nor was the subject studied with scientific purpose and method, consequently during this period chemistry was not a science."

"The Greeks were no chemists. The bent of their mind was not towards natural science; few observations or experiments were made by them, and they preferred to argue from general principles to particulars, rather than from particular observations to general principles."

"The ancient Egyptians... had a profound knowledge of the art of making, tinting, and working glass."

"The use of the expression "chemist" to indicate a druggist reminds us of another branch of alchemy, the art of making drugs which received much attention in Ancient Egypt, and probably in other eastern countries, and was combined with the art of preparing poisons and their antidotes."

"The arts and industries of dyeing, painting, and staining were known and practised in eastern lands in very ancient times. ...[T]he dyeing of skins and garments... is mentioned in most writings of antiquity. The colours used in early Egyptian art remain bright and clear. ...Remains found in Chaldea include coloured articles, as well as articles made of metal."

"[T]he Alchemical Period... may with propriety be called "The Ancient History of Chemistry.""

"The origin of the science of chemistry must... be sought in the art of alchemy. ...[I]n the course of their labours they gained much definite information regarding the properties of metals and other substances, devised the necessary apparatus and processes for chemical operations, and laid a foundation upon which later investigators have built up the modern science."

"The application of the term [alchemy] has frequently but wrongfully been restricted to the pretended arts of making gold and silver, and the more profitable arts of adulterating and of imitating gold. It had, however, a wider application, and ought to be regarded as including all the arts known in ancient times which dealt with things now comprehended in the science of chemistry."

"We are apt to suppose that the use of s is of modern origin, but that is not so. Not only did the Hebrews and the Greeks employ antiseptics in their religious rites, but in Egypt a very high degree of skill must have been attained in their preparation and use, before the body of King Rameses... and hundreds of others could have been preserved for between three and four thousand years so perfectly..."

"Lucretius pictured a solid substance as a vast number of atoms squeezed closely together, a liquid as composed of not so many atoms less tightly packed, and a gas as a comparatively small number of atoms with considerable freedom of motion. Essentially the same picture is presented by the molecular theory of to-day."

"I have... hinted at the probability that Boyle himself was involved only in a very limited way in 'his' experimental manipulations. The device which became known as the machina Boyleana [air pump] was almost certainly constructed for him by remunerated assistants Ralph Greatorex and Robert Hooke, and even the extent of Boyle's rule in its evolving design remains unclear. The glass J-shaped tube that yielded his law of pressures and volumes was again almost certainly made for him and had to be manipulated by him in collaboration with assistants, if not solely by them. The furnaces in his laboratory, and the alembics in which long-term distillations were performed, were probably tended by assistants."

"The word chemistry, in Greek should be wrote χημια, and in Latin and English chemia and chemistry; not as usual, chymia and chymistry. The first author in whom the word is found is Plutarch, who lived under the Emperors ', ', and '. That philosopher, in his treatise of ' and ', takes occasion to observe that Egypt, in the sacred dialect of the country, was called by the same name as the black of the eye viz., χημια—by which he seems to intimate that the word chemia in the Egyptian language signified black, and that the country, Egypt, might take its denomination from the blackness of the soil. ...Instead of black, some will have it originally denote secret, or occult; and hence derive it from the Hebrew chaman, or '—a mystery, whose radix is cham. And, accordingly, Plutarch observes that Egypt, in the same sacred dialect, is sometimes wrote in Greek χαμια—chamia; whence the word is easily deduced further from Cham, eldest son of Noah, by whom Egypt was first peopled after the deluge, and from whom, in the Scripture style, it is called the land of Cham, or Chem. Now, that chaman, or haman, properly signifies secret appears from the same Plutarch, who, mentioning an ancient author named Menethes Sibonita, who had asserted that Amman and Hammon were used to denote the god of Egypt, Plutarch takes this occasion to observe that in the Egyptian language anything secret or occult was called by the same name, αμμον—Hammon... Lastly, the learned Bochart, keeping to the same sense of the word, chooses to derive it from the Arabic chema, or kema—to hide; adding that there is an Arabic book of secrets called by the same name Kemi."

"Chemistry as an earnest and respectable science is often said to date from 1661, when Robert Boyle of Oxford published The Sceptical Chymist — the first work to distinguish between chemists and alchemists — but it was a slow and often erratic transition. Into the eighteenth century scholars could feel oddly comfortable in both camps — like the German Johann Becher, who produced sober and unexceptionable work on mineralogy called Physica Subterranea, but who also was certain that, given the right materials, he could make himself invisible."

"I need only remind you of Davy's great researches: nitrous oxide; electric conduction and decomposition—resulting, on the one hand, in the separation of potassium and sodium, the decomposition of the earths following as a necessary consequence, and on the other in the electro-chemical theory; iodine and chlorine—resulting in the extension and confirmation of the word element, the discovery of the so-called hydrogen acids, and the important modification of the French theory of the constitution of acids; the investigation of gaseous explosion and of flame, and the invention of the safety lamp. These are the contributions to science which stand out more prominently in connection with Davy. But over and above all this is the peculiar manner of his discoveries. He was no patient plodder. He did not elaborate his work in minute detail. He dashed it off in broad masses; but just on that account there has never been anyone to follow up his investigations. Davy's mantle fell on no one, not even on Faraday."

"The laws of thermodynamics, as empirically determined, express the approximate and probable behavior of systems of a great number of particles, or, more precisely, they express the laws of mechanics for such systems as they appear to beings who have not the fineness of perception to enable them to appreciate quantities of the order of magnitude of those which relate to single particles, and who cannot repeat their experiments often enough to obtain any but the most probable results."

"The distinction would only come to Mendeleev halfway through writing his Principles of Chemistry. ...chemical practice and not chemical theory had provided his initial organizing principle... Up to this point [Chapter 20], Mendeleev had only treated four elements in any detail: oxygen, carbon, nitrogen, and hydrogen—the so-called "organogens." Mendeleev began this chapter as usual by purifying the central substance, sodium chloride, from sources such as seawater. A discussion of sodium and chlorine followed in the next few chapters, and finally the halogens appeared... that were closely related to chlorine... and the alkali metals (the sodium family) form the first chapter of volume 2. ...he had dealt with only 8 elements, relegating 55... to the second volume. ...Mendeleev's earlier system of pedalogically useful organization—using laboratory practices... could no longer sustain the burden of exposition. He needed a new system... and he hit upon the idea of using a numerical marker for each element. Atomic weight seemed the most likely candidate for a system that would (a) account for all remaining elements; (b) do so in limited space; and (c) maintain some pedagogical merit. His solution, the periodic system, remains one of the most useful tools in chemistry."

"Why were Priestley, Boyle and Black able to see the question clearly enough to begin trying to answer it? ...because they had new tools. The air pump designed by Otto von Guericke and Boyle (...in collaboration with his assistant Robert Hooke...) were essential to Priestley's lab in Leeds. ...In a way, the air pump had enabled the entire field of pneumatic chemistry in the seventeenth century."

"[C]hemistry has always been as much about the making of products as it has been about discovering and scientifically explaining natural knowledge. It has always contained both craft and scientific components. In contemporary research in the history of chemistry, the science of chemistry is being recognized in its full extent."

"The law of conservation of mass was first put into definite form by Lavoisier, in the eighties of the eighteenth century. In considering the fermentation of fruit-juices, wherein carbonic acid gas and alcohol are produced, Lavoisier said:—"We must evidently have a complete knowledge of the analyses and the nature of the substances which can be fermented; for nothing is created, either in the operations of art, or in those of nature, and it may be laid down as a principle that, in every operation there is an equal quantity of matter before and after the operation; ...there is nothing but certain changes, certain modifications. The whole art of experimenting in chemistry rests on this principle; in all experiments one is obliged to assume an actual equality between the principles [that is, elements] of the substances examined and those obtained by the analysis of these substances. Thus, inasmuch as grape-juice yields carbonic acid gas and alcohol, I can affirm that grape juice=carbonic acid gas+alcohol.""

"On the one hand, the student has been informed by some writers that the only certain way lies in the use of the entropy-function and the thermodynamic potentials; on the other hand, he is told with equal authority that the method used by the original investigators has been the consideration of cyclic processes, and that the former method is nothing but a mathematical (perhaps unnecessary) refinement of the results obtained by the latter. These extreme attitudes appear to me to be unfortunate, and more especially when one observes the physical clearness introduced by the use of cyclic processes, but at the same time remembers that most of the results obtained by separate investigators using cyclic processes had, with a great many more, previously been found by J. Willard Gibbs by means of a purely analytical method."

"There exists in Egypt a wonderful method of dyeing. The white cloth is stained in various places, not with dye stuffs, but with substances which have the property of absorbing (fixing) colours, these applications are not visible upon the cloth; but when they are dipped into a hot caldron of the dye they are drawn out an instant after dyed. The remarkable circumstance is, that though there be only one dye in the vat, yet different colours appear upon the cloth; nor can the colour be afterwards removed."

"The emphasis on the role of 'spirits' in chemical processes helps to explain why the alchemists placed so much importance on . For, by distillation, one could drive off the 'spiritual' part of a body and collect it separately in a pure form. In this way the ancient techniques of the perfumiers acquired a new theoretical significance. The oils and perfumes driven off when rose-petals were boiled in a closed vessel appeared to to embody the very soul (or essence or attar) of the original plant. This is in fact how phrases like 'essential oils' and 'vanilla essence' originated."

"[M]etals remained the alchemists' chief concern... they seemed in their own way alive, whereas the calces (s) from which they were manufactured crumbled to dust and looked like cinders. Theory at once suggested a natural analogy. The metal was formed from the calx by the incorporation of or spirit; and this theory of metal-formation long remained in favour, being revived around 1700 as the 'phlogiston' theory. The central problem about metals was to identify the volitile constituents which combined with the calces to form the finished metal. For a long time, the status of quicksilver was ambiguous... resembling much more the volitile reagents which corrode metallic surfaces: mercury, in fact, forms an amalgam with other metals, and is even capable of dissolving gold... So the Alchemy of Avicenna classed mercury as a 'spirit' rather than a 'body'..."

"We may lay it down as an incontestible axiom, that, in all the operations of art and nature, nothing is created; an equal quantity of matter exists both before and after the experiment; the quality and quantity of the elements remain precisely the same; and nothing takes place beyond changes and modifications in the combination of these elements. Upon this principle the whole art of performing chemical experiments depends: We must always suppose an exact equality between the elements of the body examined and those of the products of its analysis."

"Chemistry is a French science. It was founded Lavoisier, of immortal memory."

"Lavoisier... was at once the author of a new theory and the creator of the true method in chemistry; and the superiority of the method gave wings to the theory. Sprung from exact observation of the phenomena of combustion, this theory was able to embrace all important facts known at that epoch. It had within itself both exactness and scope; it has become a system."

"Another objector urges—"You say the atoms are always moving, yet the things we look at, which you assert to be vast numbers of moving atoms, are often motionless." ...Lucretius answers by an analogy. " And herein you need not wonder at this, that... since they are themselves beyond what you can see, they must withdraw from sight their motion as well; and the more so, that the things which we can see do yet often conceal their motions when a great distance off.""