The history of the microscope is closely connected with that of the telescope. In the first half of the seventeenth century the simple microscope came into use. It was developed from the convex lens, which, as we have seen in a previous chapter, had been known for centuries, if not from remote antiquity. With the simple microscope Leeuwenhoek before 1673 had studied the structure of minute animal organisms and ten years later had even obtained sight of bacteria. Very early in the same century Zacharias had presented Prince Maurice, the commander of the Dutch forces, and the Archduke Albert, governor of Holland, with compound microscopes. Kircher (1601-1680) made use of an instrument that represented microscopic forms as one thousand times larger than their actual size, and by means of the compound microscope Malpighi was able in 1661 to see blood flowing from the minute arteries to the minute veins on the lung and on the distended bladder of the live frog. The Italian microscopist thus, among his many achievements, verified by observation what Harvey in 1628 had argued must take place.

In this same epoch apparatus of precision developed in other fields.

Weight clocks had been in use as time-measurers since the thirteenth century, but they were, as we have seen, difficult to control and otherwise unreliable. Even in the seventeenth century scientists in their experiments preferred some form of water-clock. In 1636 Galileo, in a letter, mentioned the feasibility of constructing a pendulum clock, and in 1641 he dictated a description of the projected apparatus to his son Vincenzo and to his disciple Viviani. He himself was then blind, and he died the following year. His instructions were never carried into effect. However, in 1657 Christian Huygens applied the pendulum to weight clocks of the old stamp. In 1674 he gave directions for the manufacture of a watch, the movement of which was driven by a spring.

Galileo, to whom the advance in exact science is so largely indebted, must also be credited with the first apparatus for the measurement of temperatures. This was invented before 1603 and consisted of a gla.s.s bulb with a long stem of the thickness of a straw. The bulb was first heated and the stem placed in water. The point at which the water, which rose in the tube, might stand was an indication of the temperature. In 1631 Jean Rey just inverted this contrivance, filling the bulb with water. Of course these thermoscopes would register the effect of varying pressures as well as temperatures, and they soon made way for the thermometer and the barometer. Before 1641 a true thermometer was constructed by sealing the top of the tube after driving out the air by heat. Spirits of wine were used in place of water. Mercury was not employed till 1670.

Descartes and Galileo had brought under criticism the ancient idea that nature abhors a vacuum. They knew that the _horror vacui_ was not sufficient to raise water in a pump more than about thirty-three feet.

They had also known that air has weight, a fact which soon served to explain the so-called force of suction. Galileo's a.s.sociate Torricelli reasoned that if the pressure of the air was sufficient to support a column of water thirty-three feet in height, it would support a column of mercury of equal weight. Accordingly in 1643 he made the experiment of filling with mercury a gla.s.s tube four feet long closed at the upper end, and then opening the lower end in a basin of mercury. The mercury in the tube sank until its level was about thirty inches above that of the mercury in the basin, leaving a vacuum in the upper part of the tube. As the specific gravity of mercury is 13, Torricelli knew that his supposition had been correct and that the column of mercury in the tube and the column of water in the pump were owing to the pressure or weight of the air.

Pascal thought that this pressure would be less at a high alt.i.tude. His supposition was tested on a church steeple at Paris, and, later, on the Puy de Dome, a mountain in Auvergne. In the latter case a difference of three inches in the column of mercury was shown at the summit and base of the ascent. Later Pascal experimented with the siphon and succeeded in explaining it on the principle of atmospheric pressure.

Torricelli in the s.p.a.ce at the top of his barometer (pressure-gauge) had produced what is called a Torricellian vacuum. Otto von Guericke, a burgomaster of Magdeburg, who had traveled in France and Italy, succeeded in constructing an air-pump by means of which air might be exhausted from a vessel. Some of his results became widely known in 1657, though his works were not published till 1673.

Robert Boyle (1626-1691), born at Castle Lismore in Ireland, was the seventh son and fourteenth child of the distinguished first Earl of Cork. He was early acquainted with these various experiments in reference to the air, as well as with Descartes' theory that air is nothing but a congeries or heap of small, and, for the most part, flexible particles. In 1659 he wrote his _New Experiments Physico-Mechanical touching the Spring of the Air_. Instead of _spring_, he at times used the word _elater_ (??at??). In this treatise he describes experiments with the improved air-pump constructed at his suggestion by his a.s.sistant, Robert Hooke.

One of Boyle's critics, a professor at Louvain, while admitting that air had weight and elasticity, denied that these were sufficient to account for the results ascribed to them. Boyle thereupon published a _Defence of the Doctrine touching the Spring and Weight of the Air_. He felt able to prove that the elasticity of the air could under circ.u.mstances do far more than sustain twenty-nine or thirty inches of mercury. In support of his view he cited a recent experiment.

He had taken a piece of strong gla.s.s tubing fully twelve feet in length.

(The experiment was made by a well-lighted staircase, the tube being suspended by strings.) The gla.s.s was heated more than a foot from the lower end, and bent so that the shorter leg of twelve inches was parallel with the longer. The former was hermetically sealed at the top and marked off in forty-eight quarter-inch s.p.a.ces. Into the opening of the longer leg, also graduated, mercury was poured. At first only enough was introduced to fill the arch, or bent part of the tube below the graduated legs. The tube was then inclined so that the air might pa.s.s from one leg to the other, and equality of pressure at the start be a.s.sured. Then more mercury was introduced and every time that the air in the shorter leg was compressed a half or a quarter of an inch, a record was made of the height of the mercury in the long leg of the tube. Boyle reasoned that the compressed air was sustaining the pressure of the column of mercury in the long leg _plus_ the pressure of the atmosphere at the tube's opening, equivalent to 29-2/16 inches of mercury. Some of the results were as follows: When the air in the short tube was compressed from 12 to 3 inches, it was under a pressure of 117-9/16 inches of mercury; when compressed to 4 it was under pressure of 87-15/16 inches of mercury; when compressed to 6, 58-13/16; to 9, 39-5/8. Of course, when at the beginning of the experiment there were 12 inches of air in the short tube, it was under the pressure of the atmosphere, equal to that of 29-2/16 inches of mercury. Boyle with characteristic caution was not inclined to draw too general a conclusion from his experiment. However, it was evident, making allowance for some slight irregularity in the experimental results, that air reduced under pressure to one half its original volume, doubles its resistance; and that if it is further reduced to one half,--for example, from six to three inches,--it has four times the resistance of common air. In fact, Boyle had sustained the hypothesis that supposes the pressures and expansions to be in reciprocal proportions.

REFERENCES

Sir Robert S. Ball, _Great Astronomers_.

Robert Boyle, _Works_ (edited by Thomas Birch).

Sir David Brewster, _Martyrs of Science_.

J. L. E. Dreyer, _Tycho Brahe_.

Sir Oliver Lodge, _Pioneers of Science_.

Flora Ma.s.son, _Robert Boyle; a Biography_.

CHAPTER VIII

COoPERATION IN SCIENCE--THE ROYAL SOCIETY

The period from 1637 to 1687 affords a good ill.u.s.tration of the value for the progress of science of the cooperation in the pursuit of truth of men of different creeds, nationalities, vocations, and social ranks.

At, or even before, the beginning of that period the need of cooperation was indicated by the activities of two men of p.r.o.nouncedly social temperament and interests, namely, the French Minim father, Mersenne, and the Protestant Prussian merchant, Samuel Hartlib.

Mersenne was a stimulating and indefatigable correspondent. His letters to Galileo, Jean Rey, Hobbes, Descartes, Ga.s.sendi, not to mention other scientists and philosophers, const.i.tute an encyclopedia of the learning of the time. A mathematician and experimenter himself, he had a genius for eliciting discussion and research by means of adroit questions.

Through him Descartes was drawn into debate with Hobbes, and with Ga.s.sendi, a champion of the experimental method. Through him the discoveries of Harvey, Galileo, and Torricelli, as well as of many others, became widely known. His letters, in the dearth of scientific a.s.sociations and the absence of scientific periodicals, served as a general news agency among the learned of his time. It is not surprising that a coterie gathered about him at Paris. Hobbes spent months in daily intercourse with this group of scientists in the winter of 1636-37.

Hartlib, though he scarcely takes rank with Mersenne as a scientist, was no less influential. Of a generous and philanthropic disposition, he repeatedly impoverished himself in the cause of human betterment. His chief reliance was on education and improved methods of husbandry, but he resembled Horace Greeley in his hospitality to any project for the public welfare.

One of Hartlib's chief hopes for the regeneration of England, if not of the whole world, rested on the teachings of the educational reformer Comenius, a bishop of the Moravian Brethren. In 1637, Comenius having shown himself rather reluctant to put his most cherished plans before the public, his zealous disciple precipitated matters, and on his own responsibility, and unknown to Comenius, issued from his library at Oxford _Preludes to the Endeavors of Comenius_. Besides Hartlib's preface it contained a treatise by the great educator on a _Seminary of Christian Pansophy_, a method of imparting an encyclopedic knowledge of the sciences and arts.

The two friends were followers of the Baconian philosophy. They were influenced, as many others of the time, by the _New Atlantis_, which went through ten editions between 1627 and 1670, and which outlined a plan for an endowed college with thirty-six Fellows divided into groups--what would be called to-day a university of research endowed by the State. It is not surprising to find Comenius (who in his student days had been under the influence of Alsted, author of an encyclopedia on Baconian lines) speaking in 1638 on the need of a collegiate society for carrying on the educational work that he himself had at heart.

In 1641 Hartlib published a work of fiction in the manner of the _New Atlantis_, and dedicated it to the Long Parliament. In the same year he urged Comenius to come to London, and published another work, _A Reformation of Schools_. He had great influence and did not hesitate to use it in his adoptive country. Everybody knew Hartlib, and he was acquainted with all the strata of English society; for although his father had been a merchant, first in Poland and later in Elbing, his mother was the daughter of the Deputy of the English Company in Dantzic and had relatives of rank in London, where Hartlib spent most of his life. He gained the good-will of the Puritan Government, and even after Cromwell's death was working, in conjunction with Boyle, for the establishment of a national council of universal learning with Wilkins as president.

When Comenius arrived in London he learned that the invitation had been sent by order of Parliament. This body was very anxious to take up the question of education, especially university education. Bacon's criticisms of Oxford and Cambridge were still borne in mind; the legislators considered that the college curriculum was in need of reformation, that there ought to be more fraternity and correspondence among the universities of Europe, and they even contemplated the endowment by the State of scientific experiment. They spoke of erecting a university at London, where Gresham College had been established in 1597 and Chelsea College in 1610. It was proposed to place Gresham College, the Savoy, or Winchester College, at the disposition of the pansophists. Comenius thought that nothing was more certain than that the design of the great Verulam concerning the opening somewhere of a universal college, devoted to the advancement of the sciences, could be carried out. The impending struggle, however, between Charles I and the Parliament prevented the attempt to realize the pansophic dream, and the Austrian Slav, who knew something of the horrors of civil war, withdrew, discouraged, to the Continent.

Nevertheless, Hartlib did not abandon the cause, but in 1644 broached Milton on the subject of educational reform, and drew from him the brief but influential tract on _Education_. In this its author alludes rather slightingly to Comenius, who had something of Bacon's infelicity in choice of t.i.tles and epithets and who must have seemed outlandish to the author of _Lycidas_ and _Comus_. But Milton joined in the criticism of the universities--the study of words rather than things--and advocated an encyclopedic education based on the Greek and Latin writers of a practical and scientific tendency (Aristotle, Theophrastus, Cato, Varro, Vitruvius, Seneca, and others). He outlined a plan for the establishment of an inst.i.tution to be known by the cla.s.sical (and Shakespearian) name "Academy"--a plan destined to have a great effect on education in the direction indicated by the friends of pansophia.

In this same year Robert Boyle, then an eager student of eighteen just returned to England from residence abroad, came under the influence of the genial Hartlib. In 1646 he writes his tutor inquiring about books on methods of husbandry and referring to the new philosophical college, which valued no knowledge but as it had a tendency to use. A few months later he was in correspondence with Hartlib in reference to the Invisible College, and had written a third friend that the corner-stones of the invisible, or, as they termed themselves, the philosophical college, did now and then honor him with their company. These philosophers whom Boyle entertained, and whose scientific ac.u.men, breadth of mind, humility, and universal good-will he found so congenial, were the nucleus of the Royal Society of London, of which, on its definite organization in 1662, he was the foremost member. They had begun to meet together in London about 1645, worthy persons inquisitive into natural philosophy--Wilkins, interested in the navigation of the air and of waters below the surface; Wallis, mathematician and grammarian; the many-sided Petty, political economist, and inventor of a double-bottomed boat, who had as a youth of twenty studied with Hobbes in Paris in 1643, and in 1648 was to write his first treatise on industrial education at the suggestion of Hartlib, and finally make a survey of Ireland and acquire large estates; Foster, professor of astronomy at Gresham College; Theodore Haak from the Pfalz; a number of medical men, Dr. Merret, Dr. Ent, a friend of Harvey, Dr. G.o.ddard, who could always be relied upon to undertake an experiment, Dr. Glisson, the physiologist, author in 1654 of a treatise on the liver (_De Hepate_), and others. They met once a week at G.o.ddard's in Wood Street, at the Bull's Head Tavern in Cheapside, and at Gresham College.

Dr. Wilkins, the brother-in-law of Cromwell, who is regarded by some as the founder of the Royal Society, removed to Oxford, as Warden of Wadham, in 1649. Here he held meetings and conducted experiments in conjunction with Wallis, G.o.ddard, Petty, Boyle, and others, including Ward (afterwards Bishop of Salisbury) interested in Bulliau's Astronomy; and the celebrated physician and anatomist, Thomas Willis, author of a work on the brain (_Cerebri Anatome_), and another on fevers (_De Febribus_), in which he described epidemic typhoid as it occurred during the Civil War in 1643.

In the mean time the weekly meetings in London continued, and were attended when convenient by members of the Oxford group. At Gresham College by 1658 it was the custom to remain for discussion Wednesdays and Thursdays after Mr. Wren's lecture and Mr. Rooke's. During the unsettled state of the country after Cromwell's death there was some interruption of the meetings, but with the accession of Charles II in 1660 there came a greater sense of security. New names appear on the records, Lord Brouncker, Sir Robert Moray, John Evelyn, Brereton, Ball, Robert Hooke, and Abraham Cowley.

[Ill.u.s.tration: _From a print of 1675_

WADHAM COLLEGE, OXFORD]

Plans were discussed for a more permanent form of organization, especially on November 28, 1660, when something was said of a design to found a college for the promotion of physico-mathematical experimental learning. A few months later was published Cowley's proposition for an endowed college with twenty professors, four of whom should be constantly traveling in the interests of science. The sixteen resident professors "should be bound to study and teach all sorts of natural, experimental philosophy, to consist of the mathematics, mechanics, medicine, anatomy, chemistry, the history of animals, plants, minerals, elements, etc.; agriculture, architecture, art military, navigation, gardening; the mysteries of all trades and improvement of them; the facture of all merchandise, all natural magic or divination; and briefly all things contained in the Catalogue of Natural Histories annexed to my Lord Bacon's _Organon_." The early official history of the Royal Society (Sprat, 1667) says that this proposal hastened very much the adoption of a plan of organization. Cowley wished to educate youth and incur great expense (4,000), but "most of the other particulars of his draught the Royal Society is now putting in practice."

A charter of incorporation was granted in July, 1662; and, later, Charles II proclaimed himself founder and patron of the Royal Society for the advancement of natural science. Charles continued to take an interest in this organization, devoted to the discovery of truth by the corporate action of men; he proposed subjects for investigation, and asked their cooperation in a more accurate measurement of a degree of lat.i.tude. He showed himself tactful to take account of the democratic spirit of scientific investigation, and recommended to the Royal Society John Graunt, the author of a work on mortality statistics first published in 1661. Graunt was a shop-keeper of London, and Charles said that if they found any more such tradesmen, they should be sure to admit them all without more ado.

It was a recognized principle of the Society freely to admit men of different religions, countries, professions. Sprat said that they openly professed, not to lay the foundation of an English, Scotch, Irish, Popish or Protestant philosophy, but a philosophy of mankind. They sought (hating war as most of them did) to establish a universal culture, or, as they phrased it, a constant intelligence throughout all civil nations. Even for the special purposes of the Society, hospitality toward all nations was necessary; for the ideal scientist, the perfect philosopher, should have the diligence and inquisitiveness of the northern nations, and the cold and circ.u.mspect and wary disposition of the Italians and Spaniards. Haak from the German Palatinate was one of the earliest Fellows of the Society, and is even credited by Wallis with being the first to suggest the meetings of 1645. Oldenburg from Bremen acted as secretary (along with Wilkins) and carried on an extensive foreign correspondence. Huygens of Holland was one of the original Fellows in 1663, while the names of Auzout, Sorbiere, the Duke of Brunswick, Bulliau, Ca.s.sini, Malpighi, Leibnitz, Leeuwenhoek (as well as Winthrop and Roger Williams) appear in the records of the Society within the first decade. It seemed fitting that this cosmopolitan organization should be located in the world's metropolis rather than in a mere university town. Sprat thought London the natural seat of a universal philosophy.

As already implied, the Royal Society was not exclusive in its att.i.tude toward the different vocations. A spirit of true fellowship prevailed in Gresham College, as the Society was sometimes called. The medical profession, the universities, the churches, the court, the army, the navy, trade, agriculture, and other industries were there represented.

Social part.i.tion walls were broken down, and the Fellows, sobered by years of political and religious strife, joined, mutually a.s.sisting one another, in the advance of science for the sake of the common weal.

Their express purpose was the improvement of all professions from the highest general to the lowest artisan. Particular attention was paid to the trades, the mechanic arts, and the fostering of inventions. One of their eight committees dealt with the histories of trades; another was concerned with mechanical inventions, and the king ordained in 1662 that no mechanical device should receive a patent before undergoing their scrutiny. A great many inventions emanated from the Fellows themselves--Hooke's hygroscope; Boyle's hydrometer, of use in the detection of counterfeit coin; and, again, the tablet anemometer used by Sir Christopher Wren (the Leonardo da Vinci of his age) to register the velocity of the wind. A third committee devoted itself to agriculture, and in the Society's museum were collected products and curiosities of the shop, mine, sea, etc. One Fellow advised that attention should be paid even to the least and plainest of phenomena, as otherwise they might learn the romance of nature rather than its true history. So bent were they on preserving a spirit of simplicity and straightforwardness that in their sober discussions they sought to employ the language of artisans, countrymen, and merchants rather than that of wits and scholars.

Of course there was in the Society a predominance of gentlemen of means and leisure, "free and unconfined." Their presence was thought to serve a double purpose. It checked the tendency to sacrifice the search of truth to immediate profit, and to lay such emphasis on application, as, in the words of a subsequent president of the Society, would make truth, and wisdom, and knowledge of no importance for their own sakes. In the second place their presence was held to check dogmatism on the part of the leaders, and subservience on the part of their followers. They understood how difficult it is to transmit knowledge without putting initiative in jeopardy and that quiet intellect is easily dismayed in the presence of bold speech. The Society accepted the authority of no one, and adopted as its motto _Nullius in Verba_.

In this att.i.tude they were aided by their subject and method. Search for scientific truth by laboratory procedure does not favor dogmatism. The early meetings were taken up with experiments and discussions. The Fellows recognized that the mental powers are raised to a higher degree in company than in solitude. They welcomed diversity of view and the common-sense judgment of the onlooker. As in the Civil War the private citizen had held his own with the professional soldier, so here the contribution of the amateur to the discussion was not to be despised.

They had been taught to shun all forms of narrowness and intolerance.

They wished to avoid the pedantry of the mere scholar, and the allied states of mind to which all individuals are liable; they valued the concurring testimony of the well-informed a.s.sembly. In the investigation of truth by the experimental method they even arrived at the view that "true experimenting has this one thing inseparable from it, never to be a fixed and settled art, and never to be limited by constant rules." In its incipience at least it is evident that the Royal Society was filled with the spirit of tolerance and cooperation, and was singularly free from the spirit of envy and faction.

Not least important of the joint labors of the Society were its publications, which established contacts and stimulated research throughout the scientific world. Besides the _Philosophical Transactions_, which, since their first appearance in 1665, are the most important source of information concerning the development of modern science, the Royal Society printed many important works, among which the following will indicate its early achievements:--

Hooke, Robert, _Micrographia: or some Physiological Descriptions of Minute Bodies made by Magnifying Gla.s.ses_. 1665.

Graunt, John, _Natural and Political Observations ... made upon the Bills of Mortality, with reference to the Government, Religion, Trade, Growth, Air, Diseases, and the several changes of the City_.

3d edition, 1665.

Sprat, Thomas, _The History of the Royal Society of London, for the Improving of Natural Knowledge_. 1667.

Malpighi, Marcello, _Dissertatio epistolica de Bombyce; Societati Regiae Londini dicata_. 1669. (On the silkworm.)