We have received from time to time, a number of letters to urge upon inventors the necessity and importance of stating the price of their machines, when illustrated and described in our columns. In many cases this no doubt, could be done, but at the same time we believe, that when we give the residence of the inventor, and state that more infor mation can be obtained by letter, the best means are presented for those desirous of purchasing said machines, or of purchasing patent rights, to obtain minute information respecting the same. Thus, for example, a patent right for one city is more valuable than lor another, and also for one State more than another.