111. History of Wax.

112. History of Basket-making.

113. History of Mat-making, and of manufactures of Straw, Rushes, and the like.

114. History of Washing, Scouring, etc.

115. History of Agriculture, Pasturage, Culture of Woods, etc.

116. History of Gardening.

117. History of Fishing.

118. History of Hunting and Fowling.

119. History of the Art of War, and of the arts thereto belonging, as Armoury, Bow-making, Arrow-making, Musketry, Ordnance, Cross-bows, Machines, etc.

120. History of the Art of Navigation, and of the crafts and arts thereto belonging.

121. History of Athletics and Human Exercises of all kinds.

122. History of Horsemanship.

123. History of Games of all kinds.

124. History of Jugglers and Mountebanks.

125. Miscellaneous History of various Artificial Materials,--Enamel, Porcelain, various cements, etc.

126. History of Salts.

127. Miscellaneous History of various Machines and Motions.

128. Miscellaneous History of Common Experiments which have not grown into an Art.

_Histories must also be written of Pure Mathematics; though they are rather observations than experiments_

129. History of the Natures and Powers of Numbers.

130. History of the Natures and Powers of Figures.

The fragment containing this catalogue (_Parasceve_--Day of Preparation) was added to Bacon's work on method, _The New Logic_ (_Novum Organum_), 1620. Besides completing his survey and cla.s.sification of the sciences (_De Augmentis Scientiarum_), 1623, he published a few separate writings on topics in the catalogue--_Winds_, _Life and Death_, _Tides_, etc. In 1627, a year after his death, appeared his much misunderstood work, _Sylva Sylvarum_. He had found that the Latin word _sylva_ meant _stuff_ or _raw material_, as well as a _wood_, and called this final work _Sylva Sylvarum_, which I would translate, "Jungle of Raw Material." He himself referred to it as "an undigested heap of particulars"; yet he was willing it should be published because "he preferred the good of men to anything that might have relation to himself." In it, following his catalogue, he fulfilled the promise made in 1620, of putting nature and the arts to question. Some of the problems suggested for investigation are: congealing of air, turning air into water, the secret nature of flame, motion of gravity, production of cold, nourishing of young creatures in the egg or womb, prolongation of life, the media of sound, infectious diseases, accelerating and preventing putrefaction, accelerating and staying growth, producing fruit without core or seed, production of composts and helps for ground, flying in the air.

In the _New Atlantis_, a work of imagination, Bacon had represented as already achieved for mankind some of the benefits he wished for: artificial metals, various cements, excellent dyes, animals for vivisection and medical experiment, instruments which generate heat solely by motion, artificial precious stones, conveyance of sound for great distances and in tortuous lines, new explosives. "We imitate,"

says the guide in the Utopian land, "also flights of birds; we have some degree of flying in the air; we have ships and boats for going under water." Bacon believed in honoring the great discoverers and inventors, and advocated maintaining a calendar of inventions.

He was a fertile and stimulating thinker, and much of his great influence arose from the comprehensiveness that led to his celebrated cla.s.sification of the sciences.

REFERENCES

Bacon's _Philosophical Works_, vol. IV, _Parasceve_, edited by R. L.

Ellis, J. Spedding, and D. D. Heath.

Karl Pearson, _Grammar of Science_.

J. A. Thomson, _Introduction to Science_.

CHAPTER VI

SCIENTIFIC METHOD--GILBERT, GALILEO, HARVEY, DESCARTES

The previous chapter has given some indication of the range of the material which was demanding scientific investigation at the end of the sixteenth and the beginning of the seventeenth century. The same period witnessed a conscious development of the method, or methods, of investigation. As we have seen, Bacon wrote in 1620 a considerable work, _The New Logic_ (_Novum Organum_), so called to distinguish it from the traditional deductive logic. It aimed to furnish the organ or instrument, to indicate the correct mental procedure, to be employed in the discovery of natural law. Some seventeen years later, the ill.u.s.trious Frenchman Rene Descartes (1596-1650) published his _Discourse on the Method of rightly conducting the Reason and seeking Truth in the Sciences_. Both of these philosophers ill.u.s.trated by their own investigations the efficiency of the methods which they advocated.

[Ill.u.s.tration: _Painting by A. Ackland Hunt_

DR. GILBERT SHOWING HIS ELECTRICAL EXPERIMENTS TO QUEEN ELIZABETH AND HER COURT]

Before 1620, however, the experimental method had already yielded brilliant results in the hands of other scientists. We pa.s.s over Leonardo da Vinci and many others in Italy and elsewhere, whose names should be mentioned if we were tracing this method to its origin. By 1600 William Gilbert (1540-1603), physician to Queen Elizabeth, before whom, as a picture in his birthplace ill.u.s.trates, he was called to demonstrate his discoveries, had published his work on the Magnet, the outcome of about eighteen years of critical research. He may be considered the founder of electrical science. Galileo, who discovered the fundamental principles of dynamics and thus laid the basis of modern physical science, although he did not publish his most important work till 1638, had even before the close of the sixteenth century prepared the way for the announcement of his principles by years of strict experiment. By the year 1616, William Harvey (1578-1657), physician at the court of James I, and, later, of Charles I, had, as the first modern experimental physiologist, gained important results through his study of the circulation of the blood.

It is not without significance that both Gilbert and Harvey had spent years in Italy, where, as we have implied, the experimental method of scientific research was early developed. Harvey was at Padua (1598-1602) within the time of Galileo's popular professoriate, and may well have been inspired by the physicist to explain on dynamical principles the flow of blood through arteries and veins. This conjecture is the more probable, since Galileo, like Harvey and Gilbert, had been trained in the study of medicine. Bacon in turn had in his youth learned something of the experimental method on the Continent of Europe, and, later, was well aware of the studies of Gilbert and Galileo, as well as of Harvey, who was indeed his personal physician.

Although these facts seem to indicate that method may be transmitted in a nation or a profession, or through personal a.s.sociation, there still remains some doubt as to whether anything so intimate as the mental procedure involved in invention and in the discovery of truth can be successfully imparted by instruction. The individuality of the man of genius engaged in investigation must remain a factor difficult to a.n.a.lyze. Bacon, whose purpose was to hasten man's empire over nature through increasing the number of inventions and discoveries, recognized that the method he ill.u.s.trated is not the sole method of scientific investigation. In fact, he definitely states that the method set forth in the _Novum Organum_ is not original, or perfect, or indispensable. He was aware that his method tended to the ignoring of genius and to the putting of intelligences on one level. He knew that, although it is desirable for the investigator to free his mind from prepossessions, and to avoid premature generalizations, interpretation is the true and natural work of the mind when free from impediments, and that the conjecture of the man of genius must at times antic.i.p.ate the slow process of painful induction. As we shall see in the nineteenth chapter, the psychology of to-day does not know enough about the workings of the mind to prescribe a fixed mental att.i.tude for the investigator.

Nevertheless, Bacon was not wrong in pointing out the virtues of a method which he and many others turned to good account. Let us first glance, however, at the activities of those scientists who preceded Bacon in the employment of the experimental method.

Gilbert relied, in his investigations, on oft-repeated and verifiable experiments, as can be seen from his work _De Magnete_. He directs the experimenter, for example, to take a piece of loadstone of convenient size and turn it on a lathe to the form of a ball. It then may be called a _terrella_, or earthkin. Place on it a piece of iron wire. The ends of the wire move round its middle point and suddenly come to a standstill. Mark with chalk the line along which the wire lies still and sticks. Then move the wire to other spots on the _terrella_ and repeat your procedure. The lines thus marked, if produced, will form meridians, all coming together at the poles. Again, place the magnet in a wooden vessel, and then set the vessel afloat in a tub or cistern of still water. The north pole of the stone will seek approximately the direction of the south pole of the earth, etc. It was on the basis of scores of experiments of this sort, carried on from about 1582 till 1600, that Gilbert felt justified in concluding that the terrestrial globe is a magnet. This theory has since that time been abundantly confirmed by navigators. The full t.i.tle of his book is _Concerning the Magnet and Magnetic Bodies, and concerning the Great Magnet the Earth: A New Natural History (Physiologia) demonstrated by many Arguments and Experiments_. It does not detract from the credit of Gilbert's result to state that his initial purpose was not to discover the nature of magnetism or electricity, but to determine the true substance of the earth, the innermost const.i.tution of the globe. He was fully conscious of his own method and speaks with scorn of certain writers who, having made no magnetical experiments, constructed ratiocinations on the basis of mere opinions and old-womanishly dreamed the things that were not.

Galileo (1564-1642) even as a child displayed something of the inventor's ingenuity, and when he was nineteen, shortly after the beginning of Gilbert's experiments, his keen perception for the phenomena of motion led to his making a discovery of great scientific moment. He observed a lamp swinging by a long chain in the cathedral of his native city of Pisa, and noticed that, no matter how much the range of the oscillations might vary, their times were constant. He verified his first impressions by counting his pulse, the only available timepiece. Later he invented simple pendulum devices for timing the pulse of patients, and even made some advances in applying his discovery in the construction of pendulum clocks.

b +---------+ | | | | | | +---------+ | | +---------+

| c | | | | | | | d | | | | e

In 1589 he was appointed professor of mathematics in the University of Pisa, and within a year or two established through experiment the foundations of the science of dynamics. As early as 1590 he put on record, in a Latin treatise _Concerning Motion_ (_De Motu_), his dissent from the theories of Aristotle in reference to moving bodies, confuting the Philosopher both by reason and ocular demonstration. Aristotle had held that two moving bodies of the same sort and in the same medium have velocities in proportion to their weights. If a moving body, whose weight is represented by _b_, be carried through the line _c--e_ which is divided in the point _d_, if, also, the moving body is divided according to the same proportion as line _c--e_ is in the point _d_, it is manifest that in the time taken to carry the whole body through _c--e_, the part will be moved through _c--d_. Galileo said that it is as clear as daylight that this view is ridiculous, for who would believe that when two lead spheres are dropped from a great height, the one being a hundred times heavier than the other, if the larger took an hour to reach the earth, the smaller would take a hundred hours? Or, that if from a high tower two stones, one twice the weight of the other, should be pushed out at the same moment, the larger would strike the ground while the smaller was still midway? His biography tells that Galileo in the presence of professors and students dropped bodies of different weights from the height of the Leaning Tower of Pisa to demonstrate the truth of his views. If allowance be made for the friction of the air, all bodies fall from the same height in equal times: the final velocities are proportional to the times; the s.p.a.ces pa.s.sed through are proportional to the squares of the times. The experimental basis of the last two statements was furnished by means of an inclined plane, down a smooth groove in which a bronze ball was allowed to pa.s.s, the time being ascertained by means of an improvised water-clock.

Galileo's mature views on dynamics received expression in a work published in 1638, _Mathematical Discourses and Demonstrations concerning Two New Sciences relating to Mechanics and Local Movements_.

It treats of cohesion and resistance to fracture (strength of materials), and uniform, accelerated, and projectile motion (dynamics).

The discussion is in conversation form. The opening sentence shows Galileo's tendency to base theory on the empirical. It might be freely translated thus: "Large scope for intellectual speculation, I should think, would be afforded, gentlemen, by frequent visits to your famous Venetian Dockyard (_a.r.s.enale_), especially that part where mechanics are in demand; seeing that there every sort of instrument and machine is put to use by numbers of workmen, among whom, taught both by tradition and their own observation, there must be some very skillful and also able to talk." The view of the shipbuilders, that a large galley before being set afloat is in greater danger of breaking under its own weight than a small galley, is the starting-point of this most important of Galileo's contributions to science.

Vesalius (1514-1564) had in his work on the structure of the human body (_De Humani Corporis Fabrica_, 1543) shaken the authority of Galen's anatomy; it remained for Harvey on the basis of the new anatomy to improve upon the Greek physician's experimental physiology. Harvey professed to learn and teach anatomy, not from books, but from dissections, not from the dogmas of the philosophers, but from the fabric of nature.

There have come down to us notes of his lectures on anatomy delivered first in 1616. A brief extract will show that even at that date he had already formulated a theory of the circulation of the blood:--

"[Ill.u.s.tration: WH monogram][1] By the structure of the heart it appears that the blood is continually transfused through the lungs to the aorta--as by the two clacks of a water-ram for raising water.