No, this quote is not from Agatha Christie. It is a variation of the proverb "The mills of the gods grind slowly, but they grind exceedingly fine," which has been attributed to various sources throughout history.
ANSWERS.com [mills-of-the-gods-grind-slowly] reports: "This expression comes from ancient Greek, translated as "The mills of the gods grind slowly, but they grind small." In English it appeared in George Herbert's Jacula Prudentum (1640) as "God's mill grinds slow but sure."
It was referenced in a poem by Friedrich von Logau in 1694: "Gottes Mühlen mahlen langsam, mahlen aber trefflich klein / Ob aus Langmut er sich säumet, bringt mit Schärf' er alles ein" which was translated by Longfellow as: "Though the mills of God grind slowly, yet they grind exceeding small; Though with patience He stands waiting, with exactness grinds He all." "They Grind Exceedingly Small" was used as the title of a short story by Ben Ames Williams publishing in the Saturday Evening Post in 1919.
"The mill of God grinds slow but grinds exceeding(ly) small" is a verbatim quote from the English translation of the Avestan language hymn book of Zoroastrianism. (Hafiz 546)
In two separate books that I know of, one being "A Pocket Full of Rye" and the other "Hercule Poirot's Christmas".
"The mills of God grind slowly, but they grind exceeding small."
Goethe
It is a traditional proverb. Correctly quoted reads 'the wheels of justice turn slowly, but grind exceedingly fine'. It may take a long time to reach the correct solution, but when it is reached it is right to the finest detail
One of your wheel bearings are bad
Slow down but proceed forward and slowly steer back on to the pavement.
Chances are you have a rock(S) stuck in your rear tire tread. pry it out.
Let off the accelerator and very slowly return to the roadway. Do not panic and do not jerk the steering wheel.
This is easier on the transmission, especially when pulling a heavy load.
When the wheels are spinning at speed they start acting as gyroscopes, steadying the bike.
Take you foot off the gas pedal, brake slightly, and slowly return to the pavement. If you do not panic and jerk the steering wheel, you will be fine.
If you apply the breaks quickly on a slick road, the wheels' rotational movement will come to a complete stop, but the car itself will keep moving forward, causing the car to slip. It happens because the force of friction, Ff, is small. The traction of the wheels on the ground (which requires that the wheels continue to roll at the speed that the ground moves past them, which is what normally happens) is what allows the driver to maintain control of the car. If the wheels suddenly were not gripping the ground, which would happen if their rotational motion stopped, the driver would have not control over the car. Slowly applying the breaks is advised because the force of friction is not exceded by the force of the breaks. In otherwords, friction (traction) still causes the wheels to roll, mainting the driver's control over the car. If the force of the breaks exceeds that of friction, then the wheels will come to a stop before the car does.
Take your foot off the accelerator, and slowly move back on the road. Do not jerk the wheel or apply the brakes.
At slow speeds the gyroscopic action of the wheels isn't much help, so it's all up to the balancing skill of the rider. Practise, practise practise!
On wheels, driven by electrical motors. It moves very slowly, transmitting pictures and data to an orbiting relay station and then to Earth; controllers on Earth review the data, and transmit new commands to the Mars rovers. Think of it as the solar system's slowest radio-controlled toy car.