arithmetical progression

The secret of this wonderful arithmetical progression may be seen in the following quotation, which applies to aphides in general: "The plant-louse of the apple-tree produces one hundred young ones in a single generation, these being born alive, and each of these brings forth others in equal number, until, at the end of the tenth generation, which is reached before the coming of frost, the original aphis has become the mother of one quintillion of her species."

The Malthusian theory,—the law of the increase of population in geometrical progression, and the increase of means of living in arithmetical progression, and the natural and prudent means of restraining the increase of population,—all these became scientific, undoubted truths which have never been verified, but, accepted as axioms, have served for further deductions.

To effect this, connect together a series of numbers increasing by arithmetical progression with a series increasing by multiplication or by mathematical progression.

The 7th term of an arithmetical progression is 17, and the 13th term is 59.

An arithmetical progression consists of 21 terms.