To those who like to observe coincidences, it may be of interest that the septcentenary of the discoverer of gunpowder should have coincided with the outbreak of the greatest war under which the world has yet groaned, even though gunpowder is no longer employed as a military propellant.英文原著 · 《Bygone Beliefs》
The second is more than 90 percent of the weight of a vehicle is in propellant. The second is more than 90 percent of the weight of a vehicle is in propellant.演讲 · 《Inside the world's deepest caves ~ Bill Stone》