Text: this allows perfectly identical buttonholes to be sewn again, until the size is changed.

Correct capitalization: This allows perfectly identical buttonholes to be sewn again, until the size is changed.

Text: at the same time, the shape of the ribs contributes to the machine having excellent depth-holding characteristics, as it is supported on a wide track.

Correct capitalization: At the same time, the shape of the ribs contributes to the machine having excellent depth-holding characteristics, as it is supported on a wide track.

Text: why should this be so? why should the species which are supposed to have been created in the galapagos archipelago, and nowhere else, bear so plain a stamp of affinity to those created in america?

Correct capitalization: Why should this be so? why should the species which are supposed to have been created in the Galapagos Archipelago, and nowhere else, bear so plain a stamp of affinity to those created in America?

Text: crude oil is also used in the production of bitumen that has been heavily used in more recent years as an alternative to tar in road building and for roof felts.

Correct capitalization:
Crude oil is also used in the production of bitumen that has been heavily used in more recent years as an alternative to tar in road building and for roof felts.