This book is available at Project Gutenberg, Internet Archive, Hathi Trust, and Google Books. Plus, there is a free Kindle ebook.
Romulus and Numa
Alba
The Elder Tarquin
Servius
Brutus
Lars Porsenna
Coriolanus
The Fabii
Cincinnatus
The Decemvirs and Virginia
Veii
Camillus
Rome and the Gauls
Rome and the Gauls continued
Manlius of the Twisted Chain
Certain Great Romans
Passes of Caudium