Whilst the greatest effort has been made to ensure the quality of this text, due to the historical nature of this content, in some rare cases there may be minor issues with legibility. It is the desire of every author, every prosecutor of research, that the products of his labours, the results of his studies, should be widely circulated. This desire arises, especially in the case of one who has devoted himself to re search, not only from a certain egotism which clings to us all, but from the wish that the laborious researches of years, often believed to refute old and generally-received errors, should become the common property Of as many as possible. The author of the present work is no exception to these general rules and it therefore gives him great pleasure, and fills him with gratitude, that you, Madam, should have taken the trouble to translate the small results of his studies into the language of Newton, and thus have rendered them more accessible to the English nation. But little more than two years have elapsed since the book first appeared in Germany, but this period has been a most important one for researches into the literature relating to Galileo.

It is the desire of every author, every prosecutor of research, that the products of his labours, the results of his studies, should be widely circulated. This desire arises, especially in the case of one who has devoted himself to re search, not only from a certain egotism which clings to us all, but from the wish that the laborious researches of years, often believed to refute old and generally-received errors, should become the common property Of as many as possible. The author of the present work is no exception to these general rules and it therefore gives him great pleasure, and fills him with gratitude, that you, Madam, should have taken the trouble to translate the small results of his studies into the language of Newton, and thus have rendered them more accessible to the English nation. But little more than two years have elapsed since the book first appeared in Germany, but this period has been a most important one for researches into the literature relating to Galileo.