ROGER BACON

ROGER BACON

Bacon was born in 1214 and died in 1292. By some it is held that

he was not appreciated in his own time because he was really a

modern scientist living in an age two centuries before modern

science or methods of modern scientific thinking were known. Such

an estimate, however, is a manifest exaggeration of t 24524i86y he facts,

although there is probably a grain of truth in it withal. His

learning certainly brought him into contact with the great

thinkers of the time, and his writings caused him to be

imprisoned by his fellow-churchmen at different times, from which

circumstances we may gather that he was advanced thinker, even if

not a modern scientist.

Although Bacon was at various times in durance, or under

surveillance, and forbidden to write, he was nevertheless a

marvellously prolific writer, as is shown by the numerous books

and unpublished manuscripts of his still extant. His

master-production was the Opus Majus. In Part IV. of this work he

attempts to show that all sciences rest ultimately on

mathematics; but Part V., which treats of perspective, is of

particular interest to modern scientists, because in this he

discusses reflection and refraction, and the properties of

mirrors and lenses. In this part, also, it is evident that he is

making use of such Arabian writers as Alkindi and Alhazen, and

this is of especial interest, since it has been used by his

detractors, who accuse him of lack of originality, to prove that

his seeming inventions and discoveries were in reality

adaptations of the Arab scientists. It is difficult to determine

just how fully such criticisms are justified. It is certain,

however, that in this part he describes the anatomy of the eye

with great accuracy, and discusses mirrors and lenses.

The magnifying power of the segment of a glass sphere had been

noted by Alhazen, who had observed also that the magnification

was increased by increasing the size of the segment used. Bacon

took up the discussion of the comparative advantages of segments,

and in this discussion seems to show that he understood how to

trace the progress of the rays of light through a spherical

transparent body, and how to determine the place of the image. He

also described a method of constructing a telescope, but it is by

no means clear that he had ever actually constructed such an

instrument. It is also a mooted question as to whether his

instructions as to the construction of such an instrument would

have enabled any one to construct one. The vagaries of the names

of terms as he uses them allow such latitude in interpretation

that modern scientists are not agreed as to the practicability of

Bacon's suggestions. For example, he constantly refers to force

under such names as virtus, species, imago, agentis, and a score

of other names, and this naturally gives rise to the great

differences in the interpretations of his writings, with

corresponding differences in estimates of them.

The claim that Bacon originated the use of lenses, in the form of

spectacles, cannot be proven. Smith has determined that as early

as the opening years of the fourteenth century such lenses were

in use, but this proves nothing as regards Bacon's connection

with their invention. The knowledge of lenses seems to be very

ancient, if we may judge from the convex lens of rock crystal

found by Layard in his excavations at Nimrud. There is nothing to

show, however, that the ancients ever thought of using them to

correct defects of vision. Neither, apparently, is it feasible to

determine whether the idea of such an application originated with

Bacon.

Another mechanical discovery about which there has been a great

deal of discussion is Bacon's supposed invention of gunpowder. It

appears that in a certain passage of his work he describes the

process of making a substance that is, in effect, ordinary

gunpowder; but it is more than doubtful whether he understood the

properties of the substance he describes. It is fairly well

established, however, that in Bacon's time gunpowder was known to

the Arabs, so that it should not be surprising to find references

made to it in Bacon's work, since there is reason to believe that

he constantly consulted Arabian writings.

The great merit of Bacon's work, however, depends on the

principles taught as regards experiment and the observation of

nature, rather than on any single invention. He had the

all-important idea of breaking with tradition. He championed

unfettered inquiry in every field of thought. He had the instinct

of a scientific worker--a rare instinct indeed in that age. Nor

need we doubt that to the best of his opportunities he was

himself an original investigator.