Part 3

In the same year (1661) Boyle published "Some Considerations on the Usefulness of Experimental Natural Philosophy," etc., and in 1663 an extremely interesting paper on "Experiments and Considerations touching Colours." In the course of this paper he describes some very beautiful experiments with a tincture of _Lignum nephriticum_, wherein the dichroism of the extract is made apparent. Boyle found that by transmitted light it appeared of a bright golden colour, but when viewed from the side from which it was illuminated the light emitted was sky blue, and in some cases bright green. By arranging experiments so that some parts of the liquid were seen by the transmitted light and some by the scattered light, very beautiful effects were produced. Boyle endeavoured to learn something of the nature of colours by projecting spectra on differently coloured papers, and observing the appearance of the papers when illuminated by the several spectral rays. He also passed sunlight, concentrated by a lens, through plates of differently coloured glass superposed, allowing the light to fall on a white paper screen, and observing the tint of the light which passed through each combination. But the most interesting of these experiments was the actual mixture of light of different colours by forming two spectra, one by means of a fixed prism, the other by a prism held in the hand, and superposing the latter on the former so that different colours were made to coincide. This experiment was repeated in a modified form, nearly two hundred years later, by Helmholtz, who found that the mixture of blue and yellow lights produced pink. Unfortunately, Boyle's spectra were far from pure, for, the source of light being of considerable dimensions, the different colours overlapped one another, as in Newton's experiments, and in consequence some of his conclusions were inaccurate. Thus blue paper in the yellow part of the spectrum appeared to Boyle green instead of black, but this was due to the admixture of green light with the yellow. He concluded that bodies appear black because they damp the light so as to reflect very little to the eye, but that the surfaces of white bodies consist of innumerable little facets which reflect the light in all directions. In the same year he published some "Observations on a Diamond, which shines in the Dark;" and an extensive treatise on "Some Considerations touching the Style of the Holy Scriptures." Next year appeared several papers from his pen, the most important being "Occasional Reflections upon Several Subjects," the wide scope of which may be gathered from the title. His "New Experiments and Observations touching Cold" were printed in 1665. In this paper he discussed the cause of the force exerted by water in freezing, methods of measuring degrees of cold, the action of freezing-mixtures, and many other questions. He contended that cold was probably only privative, and not a positive existence.

Lord Bacon had asserted that the "essential self" of heat was probably motion and nothing more, and had adduced several experiments and observations in support of this opinion. In his paper on the mechanical origin of heat and cold, Boyle maintained that heat was motion, but motion of the very small particles of bodies, very intense, and taking place in all directions; and that heat could be produced by any means whatever by which the particles of bodies could be agitated. On one occasion he caused two pieces of brass, one convex and the other concave, to be pressed against each other by a spring, and then rubbed together in a vacuum by a rotary motion communicated by a shaft which passed air-tight through the hole in the cover of the receiver, a little emery being inserted between them. In the second experiment the brasses became so hot that he "could not endure to hold [his] hand on either of them." This experiment was intended, like the rubbing of the blocks of ice in vacuo by Davy, to meet the objection that the heat developed by friction was due to the action of the air. The following extract from a paper intended to show that the sense of touch cannot be relied upon for the estimation of temperature, shows that Boyle possessed a very clear insight into the question:--"The account upon which we judge a body to be cold seems to be that we feel its particles less vehemently agitated than those of our fingers or other parts of the organ of touching; and, consequently, if the temper of that organ be changed, the object will appear more or less cold to us, though itself continue of one and the same temperature." To determine the expansion of water in freezing, he filled the bulb and part of the stem of a "bulb tube," or, as it was then generally called, "a philosophical egg," with water, and applying a freezing-mixture, at first to the bottom of the bulb, he succeeded in freezing the water without injury to the glass, and found that 82 volumes of water expanded to 91-1/8 volumes of ice--an expansion of about 11-1/8 per cent. Probably air-bubbles caused the ice to appear to have a greater volume than it really possessed, the true expansion being about nine per cent. of the volume of the water at 4°C. The expansion of water in freezing he employed in order to compress air to a greater extent than he had been able otherwise to compress it. Having nearly filled a tube with water, but left a little air above, and then having sealed the top of the tube, he froze the water from the bottom upwards, so that in expanding it compressed the air to one-tenth of its former volume.

Magnetism and electricity came in for some share of Boyle's attention. He carried out a number of experiments on magnetic induction, and found that lodestones, as well as pieces of iron, when heated and allowed to cool, became magnetized by the induction of the earth. His later experiments with exhausted receivers were not made with his first pump, but with a two-barrelled pump, in which the pistons were connected by a cord passing over a large fixed pulley, so that, when the receiver was nearly exhausted, the pressure of the air on the descending piston during the greater part of the stroke nearly balanced that on the ascending piston. In this respect the pump differed only from Hawksbee's in having the pulley and cord instead of the pinion and two racks. It also resembled Hawksbee's pump in having self-closing valves in the pistons and at the bottom of the cylinders, which, in this pump, had their open ends at the top. The pistons were alternately raised and lowered by the feet of the operator, which were placed in stirrups, of which one was fixed on each piston. The lower portions of the barrels were filled with water, through which the air bubbled, and this, occupying the clearance, enabled a much higher degree of exhaustion to be produced than could be obtained without its employment.

In 1665 Boyle was nominated Provost of Eton, but declined to accept the appointment. His "Hydrostatical Paradoxes," published about this time, contain all the ordinary theorems respecting the pressure of fluids under the action of gravity demonstrated experimentally.

In 1677 Boyle printed, at his own expense, five hundred copies of the four Gospels and the Acts of the Apostles in the Malayan tongue. This was but one of his many contributions towards similar objects.

On November 30, 1680, the Royal Society chose Boyle for President. He, however, declined to accept the appointment, because he had conscientious objections to taking the oath required of the President by the charter of the Society.

It appears that very many of Boyle's manuscripts, which were written in bound books, were taken away, and others mutilated by "corrosive liquors." In May, 1688, he made this known to his friends, but, though these losses put him on his guard, he complained afterwards that all his care and circumspection had not prevented the loss of "six centuries of matters of fact in one parcel," besides many other smaller papers. His works, however, which have been published are so numerous that it would take several pages for the bare enumeration of their titles, many of them being devoted to medical subjects. The edition published in London in 1743 comprises nearly three thousand pages of folio. Boyle always suffered from weak eyes, and in consequence he declined to revise his proofs. In the advertisement to the original edition of his works the publisher mentioned this, and at the same time pleaded his own business engagements as an excuse for not revising the proofs himself! It was partly on account of the injury to his manuscripts, and partly through failing health, that in 1689 he set apart two days in the week, during which he declined to receive visitors, that he might devote himself to his work, and especially to the reparation of the injured writings. About this time he succeeded in procuring the repeal of an Act passed in the fifth year of Henry IV. to the effect "that none from thenceforth should use to multiply gold or silver, or use the craft of multiplication; and if any the same do, they should incur the pain of felony." By this repeal it was made legal to extract gold and silver from ores, or from their mixtures with other metals, in this country provided that the gold and silver so procured should be put to no other use than "the increase of moneys." It is curious that Boyle seems always to have believed in the possibility of transmuting other metals into gold.

His sister, Lady Ranelagh, died on December 23, 1691, and Boyle survived her but a few days, for he died on December 30, and his body was interred near his sister's grave in the chancel of St. Martin's-in-the-Fields. Dr. Shaw, in his preface to Boyle's works, writes, "The men of wit and learning have, in all ages, busied themselves in explaining nature by words; but it is Mr. Boyle alone who has wholly laid himself out in showing philosophy in action. The single point he perpetually keeps in view is to render his reader, not a talkative or a speculative, but an actual and practical philosopher. Himself sets the example; he made all the experiments he possibly could upon natural bodies, and communicated them with all desirable candour and fidelity." The second part of his treatise on "The Christian Virtuoso," Boyle concluded with a number of aphorisms, of which the following well represent his views respecting science:--

"I think it becomes Christian philosophers rather to try whether they can investigate the final causes of things than, without trial, to take it for granted that they are undiscoverable."

"The book of Nature is a fine and large piece of tapestry rolled up, which we are not able to see all at once, but must be content to wait for the discovery of its beauty and symmetry, little by little, as it gradually comes to be more unfolded or displayed."

BENJAMIN FRANKLIN.

Among those whose contributions to physics have immortalized their names in the annals of science, there is none that holds a more prominent position in the history of the world than Benjamin Franklin. At one time a journeyman printer, living in obscure lodgings in London, he became, during the American War of Independence, one of the most conspicuous figures in Europe, and among Americans his reputation was probably second to none, General Washington not excepted.

Professor Laboulaye says of Franklin: "No one ever started from a lower point than the poor apprentice of Boston. No one ever raised himself higher by his own unaided forces than the inventor of the lightning-rod. No one has rendered greater service to his country than the diplomatist who signed the treaty of 1783, and assured the independence of the United States. Better than the biographies of Plutarch, this life, so long and so well filled, is a source of perpetual instruction to all men. Every one can there find counsel and example."

A great part of the history of his life was written by Franklin himself, at first for the edification of the members of his own family, and afterwards at the pressing request of some of his friends in London and Paris. His autobiography does not, however, comprise much more than the first fifty years of his life. The first part was written while he was the guest of the Bishop of St. Asaph, at Twyford; the second portion at Passy, in the house of M. de Chaumont; and the last part in Philadelphia, when he was retiring from public life at the age of eighty-two. The former part of this autobiography was translated into French, and published in Paris, in 1793, though it is not known how the manuscript came into the publisher's hands. The French version was translated into English, and published in England and America, together with such other of Franklin's works as could be collected, before the latter part was given to the world by Franklin's grandson, to whom he had bequeathed his papers, and who first published them in America in 1817.

For a period of three hundred years at least Franklin's family lived on a small freehold of about thirty acres, in the village of Ecton, in Northamptonshire, the eldest son, who inherited the property, being always brought up to the trade of a smith. Franklin himself "was the youngest son of the youngest son for five generations back." His grandfather lived at Ecton till he was too old to follow his business, when he went to live with his second son, John, who was a dyer at Banbury. To this business Franklin's father, Josiah, was apprenticed. The eldest son, Thomas, was brought up a smith, but afterwards became a solicitor; the other son, Benjamin, was a silk-dyer, and followed Josiah to America. He was fond of writing poetry and sermons. The latter he wrote in a shorthand of his own inventing, which he taught to his nephew and namesake, in order that he might utilize the sermons if, as was proposed, he became a Presbyterian minister. Franklin's father, Josiah, took his wife and three children to New England, in 1682, where he practised the trade of a tallow-chandler and soap-boiler. Franklin was born in Boston on January 6 (O.S.), 1706, and was the youngest of seventeen children, of whom thirteen grew up and married.

Benjamin being the youngest of ten sons, his father intended him for the service of the Church, and sent him to the grammar school when eight years of age, where he continued only a year, although he made very rapid progress in the school; for his father concluded that he could not afford the expense of a college education, and at the end of the year removed him to a private commercial school. At the age of ten young Benjamin was taken home to assist in cutting the wicks of candles, and otherwise to make himself useful in his father's business. His enterprising character as a boy is shown by the following story, which is in his own words:--

There was a salt marsh that bounded part of the mill-pond, on the edge of which, at high-water, we used to stand to fish for minnows. By much trampling we had made it a mere quagmire. My proposal was to build a wharf there fit for us to stand upon, and I showed my comrades a large heap of stones, which were intended for a new house near the marsh, and which would very well suit our purpose. Accordingly, in the evening, when the workmen were gone, I assembled a number of my play-fellows, and working with them diligently, like so many emmets, sometimes two or three to a stone, we brought them all away and built our little wharf. The next morning the workmen were surprised at missing the stones, which were found in our wharf. Inquiry was made after the removers; we were discovered and complained of; several of us were corrected by our fathers; and, though I pleaded the usefulness of the work, mine convinced me that nothing was useful which was not honest.

Until twelve years of age Benjamin continued in his father's business, but as he manifested a great dislike for it, and his parents feared that he might one day run away to sea, they set about finding some trade which would be more congenial to his tastes. With this view his father took him to see various artificers at their work, that he might observe the tastes of the boy. This experience was very valuable to him, as it taught him to do many little jobs for himself when workmen could not readily be procured. During this time Benjamin spent most of his pocket-money in purchasing books, some of which he sold when he had read them, in order to buy others. He read through most of the books in his father's very limited library. These mainly consisted of works on theological controversy, which Franklin afterwards considered to have been not very profitable to him.

"There was another bookish lad in the town, John Collins by name, with whom I was intimately acquainted. We sometimes disputed, and very fond we were of argument, and very desirous of confuting one another, which disputatious turn, by the way, is apt to become a very bad habit, making people often very disagreeable in company by the contradiction that is necessary to bring it into practice; and thence, besides souring and spoiling the conversation, is productive of disgusts and perhaps enmities when you may have occasion for friendship. I had caught it by reading my father's books of dispute about religion. Persons of good sense, I have since observed, seldom fall into it, except lawyers, university men, and men of all sorts that have been bred at Edinburgh."

At length Franklin's fondness for books caused his father to decide to make him a printer. His brother James had already entered that business, and had set up in Boston with a new press and types which he had brought from England. He signed his indentures when only twelve years old, thereby apprenticing himself to his brother until he should attain the age of twenty-one. The acquaintance which he formed with booksellers through the printing business enabled him to borrow a better class of books than he had been accustomed to, and he frequently sat up the greater part of the night to read a book which he had to return in the morning.

While working with his brother, the young apprentice wrote two ballads, which he printed and sold in the streets of Boston. His father, however, ridiculed the performance; so he "escaped being a poet." He adopted at this time a somewhat original method to improve his prose writing. Meeting with an odd volume of the _Spectator_, he purchased it and read it "over and over," and wished to imitate the style. "Making short notes of the sentiment in each sentence," he laid them by, and afterwards tried to write out the papers without looking at the original. Then on comparison he discovered his faults and corrected them. Finding his vocabulary deficient, he turned some of the tales into verse, then retranslated them into prose, believing that the attempt to make verses would necessitate a search for several words of the same meaning. "I also sometimes jumbled my collection of hints into confusion, and after some weeks endeavoured to reduce them into the best order, before I began to form the full sentence and complete the paper. This was to teach me method in the arrangement of my thoughts."

Meeting with a book on vegetarianism, Franklin determined to give the system a trial. This led to some inconvenience in his brother's house-keeping, so Franklin proposed to board himself if his brother would give him half the sum he paid for his board, and out of this he was able to save a considerable amount for the purpose of buying books. Moreover, the time required for meals was so short that the dinner hour afforded considerable leisure for reading. It was on his journey from Boston to Philadelphia that he first violated vegetarian principles; for, a large cod having been caught by the sailors, some small fishes were found in its stomach, whereupon Franklin argued that if fishes ate one another, there could be no reason against eating them, so he dined on cod during the rest of the journey.

After reading Xenophon's "Memorabilia," Franklin took up strongly with the Socratic method of discussion, and became so "artful and expert in drawing people, even of superior knowledge, into concessions, the consequence of which they did not foresee," that some time afterwards one of his employers, before answering the most simple question, would frequently ask what he intended to infer from the answer. This practice he gradually gave up, retaining only the habit of expressing his opinions with "modest diffidence."

In 1720 or 1721 James Franklin began to print a newspaper, the _New England Courant_. To this paper, which he helped to compose and print, Benjamin became an anonymous contributor. The members of the staff spoke highly of his contributions, but when the authorship became known, James appears to have conceived a jealousy of his younger brother, which ultimately led to their separation. An article in the paper having offended the Assembly, James was imprisoned for a month and forbidden to print the paper. He then freed Benjamin from his indentures, in order that the paper might be published in his name. At length, some disagreement arising, Benjamin took advantage of the cancelling of his indentures to quit his brother's service. As he could get no employment in Boston, he obtained a passage to New York, whence he was recommended to go to Philadelphia, which he reached after a very troublesome journey. His whole stock of cash then consisted of a Dutch dollar and about a shilling's worth of coppers. The coppers he gave to the boatmen with whom he came across from Burlington. His first appearance in Philadelphia, about eight o'clock on a Sunday morning, was certainly striking. A youth between seventeen and eighteen years of age, dressed in his working clothes, which were dirty through his journey, with his pockets stuffed out with stockings and shirts, his aspect was not calculated to command respect.

"Then I walked up the street, gazing about till near the market-house I met a boy with bread. I had made many a meal on bread, and, inquiring where he got it, I went immediately to the baker's he directed me to, in Second Street, and ask'd for bisket, intending such as we had in Boston; but they, it seems, were not made in Philadelphia. Then I asked for a threepenny loaf, and was told they had none such. So, not considering or knowing the difference of money, and the greater cheapness, nor the name of his bread, I bad him give me three-penny-worth of any sort. He gave me, accordingly, three great puffy rolls. I was surpriz'd at the quantity, but took it, and having no room in my pockets, walk'd off with a roll under each arm, and eating the other. Thus I went up Market Street as far as Fourth Street, passing by the door of Mr. Read, my future wife's father; when she, standing at the door, saw me, and thought I made, as I certainly did, a most awkward, ridiculous appearance. Then I turned and went down Chestnut Street and part of Walnut Street, eating my roll all the way, and, coming round, found myself again at Market Street Wharf, near the boat I came in, to which I went for a draught of the river water; and, being filled out with one of my rolls, gave the other two to a woman and her child that came down the river in the boat with us, and were waiting to go further."