The first important change in the machine, was the adaptation of his pole changer to the machine, in place of the break pieces, which were used in all the modifications up to that time; and another equally useful improvement, consisted in the arrangement of the permanent magnets and armatures. Previous to this last improvement, these machines were constructed with a single permanent magnet, and one or more revolving armatures, necessarily involving great disadvantages. Page’s improvements were completed in February, 1838, and shortly after published in Silliman’s Journal. He was also the first to suggest the combination of several machines under one mechanical movement, as the best mode of augmenting power in this way. _The combined machine, described in Daniell’s Introduction to Chemical Philosophy, as invented by Wheatstone, about two years since, is the same as that described, and represented by Dr. Page in Silliman’s Journal in 1838._ In the same publication, Dr. Page described the arrangement of the permanent magnets and armatures, as shown in the annexed figures. The adaptation of the pole changer, which, in connection with this machine, is called the _Unitrep_, Dr. Page has given to the public. But as he has never allowed the improvement, which consists in the use of two or more permanent magnets and straight armatures, to be sold with his knowledge and consent, he intends to claim a _patent for the same_; it having been decided by our courts, that the publication of an invention by the inventor, does not affect his right to a patent, provided he does not allow the invention to be sold and used. The figures 45, 46 and 47, exhibit one of Page’s machines with his early improvements. Figure 45, is a side elevation of the machine. Figure 46, is a top view. Figure 47, are views of the revolving armatures and coils.