Bacon | Francis
Roger Bacon is not to be confused with Francis Bacon
In 1265, Bacon, inspired by the Aristotelian commentaries of Robert Grosseteste (1235), which laid out the framework for proper methods of science, described a scientific method, which he based on a repeating cycle of observation, hypothesis, experimentation, and the need for independent verification; and he recorded the manner in which he conducted his experiments in precise detail so that others could reproduce and independently test his results. (Ѻ)
Influenced | By
Bacon was a contemporary of Albertus Magnus, whom he may have known at Paris during the years 1245-1248, and together they are considered the two main commentators on the new translations of Aristotle, in the university milieu, during the thirteenth century. 
In c.1250, Bacon, at Paris, met a scientist named Petrus Peregrinus
), whom he called the "master of the experiment", who influenced him in respect to the power of experimentation; to quote on example:
“There is only one scholar, namely, Petrus Peregrinus, who understands the nature of the truth of the superiority of experiment over argument.”
— Roger Bacon (c.1270) (Ѻ)
he gains knowledge
of the things pertaining to nature
and medicine and alchemy, and all that is in heaven
and in the earth
— Roger Bacon (c.1270), on Petrus Peregrinus (Ѻ)
On experimentation and truth, Bacon said:
“Argument is conclusive, but it does not remove doubt, so that the mind may not rest in the sure knowledge of the truth, unless it finds it by the method of experiment.”
Bacon was said to have been one of the first to experimentally test the hot-begets-cold-quicker phenomenon (Aristotle-Mpemba effect). 
Bacon, whose works have been analyzed by scholar including James Partington and Joseph Needham, was one of the first to describe explosive combustion, a noted statement of which, by Bacon, is as follows: 
“We have an example of these things (that act on the senses) in [the sound and fire of] that children's toy which is made in many [diverse] parts of the world; i.e. a device no bigger than one's thumb. From the violence of that salt called saltpetre [together with sulphur and willow charcoal, combined into a powder] so horrible a sound is made by the bursting of a thing so small, no more than a bit of parchment [containing it], that we find [the ear assaulted by a noise] exceeding the roar of strong thunder, and a flash brighter than the most brilliant lightning.”
| A depiction of Bacon studying “long after the midnight hour” (Ѻ). |
American historian Stephen Bown dates Bacon's so-called documentation of the secret of gunpowder to the year circa 1249 in the timeline of explosives. 
In 1277, Bacon was imprisoned, for a period of 10-15 years, by Jerome of Ascali, minster general of the Franciscans, by the advise of "many friars", and his teachings were denounced.  Released, he wrote one more innovative book before dying (ending) and becoming a Faust-like figure of legend. 
Quotes | On
The following are related notes of praise:
“Roger Bacon — the founder of English philosophy whose knowledge of chemistry and mathematics led him to recognize the value of deductive reasoning, establish a scientific method, and invent spectacles — has been called the last man to know everything, the last man to bridge the two cultures.”
— Rushworth Kidder (2003), How Good People Make Tough Choices 
“Roger Bacon, a humble and devout English friar, seems an unlikely figure to challenge the orthodoxy of his day — yet he risked his life to establish the basis for true knowledge. Born c.1220, Bacon was passionately interested in the natural world and how things worked. Such dangerous topics were vetoed by his Order, and it was only when a new Pope proved sympathetic that he began compiling his encyclopedia on everything from optics to alchemy — the synopsis took a year and ran to 800,000 words and he was never to complete the work itself. Sadly, the enlightened Pope died, and Bacon was tried as a magician and incarcerated for ten years. Legend transformed Bacon into a sorcerer, 'Doctor Mirabilis', yet he taught that all magic was based on fraud, and his books were the first flowering of the scientific thinking that would transform our world. He advanced the understanding of optics, made geographical breakthroughs later used by Columbus, predicted everything from horseless carriages to the telescope, and stressed the importance of mathematics to science, a significance ignored for 400-years. His biggest contribution was to insist that a study of the natural world by observation and exact measurement was the surest foundation for truth.”
— Brain Clegg (2003), abstract to Roger Bacon: the First Scientist 
Quotes | By
The following are noted quotes
“During the twenty years that I have specially laboured in the attainment of wisdom, abandoning the vulgar path, I have spent upon these pursuits more than two thousand pounds, not to mention the cost of secret books, of various experiments, instruments, tables, and the like.”
— Roger Bacon (1267) (Ѻ)
“If someone who has never seen fire claims through reasoning that fire burns, changes things and destroys them, the mind of his listener will not be satisfied with that, and will not avoid fire before he has placed his hand or something combustible on the fire, to prove through experience what his reasoning had taught him. But one it has had the experience of combustion the mind is assured and rests in the light of truth. Reasoning is not enough—one needs experience.”
— Roger Bacon (c.1275) 
“The surest way of extirpating all the heresies, and of destroying the kingdom of the antichrist, and of establishing ‘true religion’ in the hearts of men, is by perfecting a true system of natural philosophy.”
— Roger Bacon (c.1275), Publication; cited Oliver Reiser (1940) in The Promise of Scientific Humanism (pg. 227)
1. Graves, Dan. (1996). Scientists of Faith: Forty-Eight Scientists and Their Christian Faiths (pg. 24). Kregel Resources.
2. Kidder, Rushworth M. (2003). How Good People Make Tough Choices (pg. 147). Harper Collins.
3. (a) Bacon, Roger. (date). Opus Maius (or Opus Tertium). Publisher.
(b) Needham, Joseph, Lu, Gwei-Djen, and Wang, Lin. (1987). Science and Civilisation in China, Volume 5, Part 7 (pgs. 48–50). Cambridge University Press.
(c) Gunpowder (section) – Wikipedia.
4. Bown, Stephen R. (2005). A Most Damnable Invention: Dynamite, Nitrates, and the Making of the Modern World (pg. ix, 14-16). MacMillan.
5. Clegg, Brian. (2003). The First Scientist: a Life of Roger Bacon. Da Capo Press.
6. Hackett, Jeremiah M.G. (1980). “The Attitude of Roger Bacon to the Scientia of Albertus Magnus”, in: Albertus Magnus and the Sciences: Commemorative Essays 1980, Volumes 49-50 (editor: James Weisheipl) (§2, pgs. 53-). Pontifical Institute of Medieval Studies.
● Roger Bacon – Wikipedia.