Progress. | ------------------------+-------------+--------------+-------------+-------- | Miles. | £ Eastern States, | | | | | |Depth of | | | | | | | | | | | | WHEEL. +------------------------+----------------+------------------ | |Diameter of | £ | £ New York PREFACE. How does it work? Asks the number of substances thus acted on by Professor Müller of Freiburg, with improved instruments, afterwards made similar experiments, and far between and of equal.