K Mendělejovi by asi neškodilo uvést pohled tohoto fenomenálního chemika na vznik ropy:

"The capital fact to note is that petroleum was born in the depths of the Earth, and only there we must seek its origin.

So what are these hydrocarbons?

It is probably that these are precisely those of oil. White iron treated by acid gives, it is true, other carbides [carbon compounds] less rich in hydrogen, but if these carbides formed under the influence of high temperature and high pressure conditions (carried out in the depths of globe), they would not fail, according to Mr. Berthelot to become saturated hydrocarbons, similar to those oil. Thus, starting form the fact that the oil cannot have an organic origin I sought to explain otherwise its production mode.
The explanation I was given from the disposal of oil sources, the proportion of metals was likely inside the earth, by the passage of water through cracks and by the action of metal carbides on water, such as cast iron."

Dmitri Ivanovich Mendeleev, L'Origine du Petrole, 1877