To pass judgment on the recording machines of the patents that have been described, from the invention of Barbour to that of Burroughs, demands consideration, first, as to whether in any of the machines of these patents the primary features of legible recording were present. The question as to operativeness respecting other features is of no consideration until it is proven that the means disclosed for recording was practical. As non-recording adding or calculating machines they were not of a type that could compete with the more speedy key-driven machines dealt with in the preceding chapters; therefore without the capacity for legible recording, these patents must stand as representing a nonentity or as statutory evidence of the ineffective efforts of those who conceived the scheme of their make-up and attempted to produce a recording-adding machine. Without the capacity for legible recording, of what avail is it that the machine of one of these patents should disclose advantages over another? It may be conceded that there are features set forth in the Pottin and Burroughs patents that if operatively combined with legible recording would disclose quite an advanced state of the Art at the time they were patented. But credit for such an operative combination cannot be given until it exists. There is no desire to question the ingenuity displayed by any of these inventors, but in seeking the first practical recording-adding or calculating machine we must first find an operative machine of that type; one which will record in a practical and legible manner regardless of its other qualifications. [Sidenote: _Practical method for recording disclosed later_] The fact that the fundamental principle used for the impression of the type in the practical recorder of today is not displayed in any of these inventions, raises the question as to the effective operativeness of the printing scheme disclosed in the patents of these early machines. In each of the four alleged recording-adding machine patents described, it will be noted that the means employed for printing was that of pressing the paper against the group of type by means of a universal platen or plate. While with such a combination it may be possible to provide a set pressure great enough to legibly print a numerical item or total having eight to ten figures through an ink ribbon, it would not be practical to use the same pressure to print a single-digit figure, as it would cause the type to break through the paper. And yet in the numerical items and totals that have to be recorded in machines of the class under consideration, such wide variation is constantly encountered.