Jethro Wood took out two plow patents, and those who wish to belittle his work, descant upon the first as if it were his only claim to credit. That first patent was issued in 1814. It fell far short of satisfying the patentee's ambition. The plows made under it must have been a great improvement on any then in use, for although he abandoned it almost from the first, a great many of them were sold during the period between the first and the second patents. The second patent dates from 1819. The natal day of the modern plow may be fairly set down as September 1, 1819. The original specifications in this plow deserve to be given in full, and may well be inserted in this connection. The document was the handiwork of Mr. Wood himself, and runs thus: "The Schedule referred to in these Letters Patent, and making part of the same, containing a description in the words of the said Jethro Wood himself of his improvement in the construction of Ploughs. "Considering the manifold errors and defects in the construction of Ploughs, and the inconveniences experienced in the use of them, the petitioner and inventor hath applied the powers of his mind to the improvement of this noble utensil, and produced a Plough so far superior to those in common use, that he asks an exclusive privilege for the same from the government of his country. "The principal matters for which he solicits Letters Patent, he now reduces to writing, and explains in words and sentences as appropriate and significant as he possibly can. But, being perfectly aware of the feebleness and insufficiency of language to convey precise and adequate ideas of complicated forms and proportions, the said Jethro Wood annexes to these presents, a delineation upon paper of his said new and improved Plough, with full and explanatory notes; urging with earnestness and respect that the delineation and notes may be considered as a part of this communication. The said petitioner and inventor also, being perfectly convinced, as a practical man, that a model of his inventions and improvements will convey and preserve the most exact and durable impressions of the matters to which he lays claim, he sends herewith a model of the due form and proportion of each, as a just exhibition of his principle and of its application to the construction and improvement of the Plough, requesting that the same may be kept in the Patent Office, as a perpetual memorial of the invention and its use. "In the first place, the said Jethro Wood claims an exclusive privilege for constructing the part of the Plough, heretofore, and to this day, generally called the mould-board, _in the manner hereinafter mentioned_. This mould-board may be termed a plano-curvilinear figure, not defined nor described in any of the elementary books of geometry or mathematics. But an idea may be conceived of it thus: