"How beautiful the leaves grow old. How full of light and color are their last days."

"Travel and society polish one, but a rolling stone gathers no moss, and a little moss is a good thing on a man."

"Joy in the universe, and keen curiosity about it all - that has been my religion."

"For anything worth having one must pay the price; and the price is always work, patience, love, self-sacrifice - no paper currency, no promises to pay, but the gold of real service."

"One may summon his philosophy when they are beaten in battle, not till then."

"The lure of the distant and the difficult is deceptive. The great opportunity is where you are."

"The spirit of man can endure only so much and when it is broken only a miracle can mend it."

"Science has done more for the development of western civilization in one hundred years than Christianity did in eighteen hundred years."

"Nature teaches more than she preaches. There are no sermons in stones. It is easier to get a spark out of a stone than a moral."

"Leap, and the net will appear."

"A man can get discouraged many times but he is not a failure until he begins to blame somebody else and stops trying."

"If we take science as our sole guide, if we accept and hold fast that alone which is verifiable, the old theology must go."

"A man can fail many times, but he isn't a failure until he begins to blame somebody else."

"To treat your facts with imagination is one thing, to imagine your facts is another."

"Blessed is the man who has some congenial work, some occupation in which he can put his heart, and which affords a complete outlet to all the forces there are in him."

"The Kingdom of Heaven is not a place, but a state of mind."

"The smallest deed is better than the greatest intention."

"The secret of happiness is something to do."

"Life is a struggle, but not a warfare."

"To learn something new, take the path that you took yesterday."

"I go to nature to be soothed and healed, and to have my senses put in order."

"I seldom go into a natural history museum without feeling as if I were attending a funeral."

"Some men are like nails, very easily drawn; others however are more like rivets never drawn at all."

"I have discovered the secret of happiness - it is work, either with the hands or the head. The moment I have something to do, the draughts are open and my chimney draws, and I am happy."

"I still find each day too short for all the thoughts I want to think, all the walks I want to take, all the books I want to read, and all the friends I want to see."

"There is hardly a man on earth who will take advice unless he is certain that it is positively bad."

"To me - old age is always ten years older than I am."