A letter of John Evelyn Esq;, to the Right Honourable the Lord Viscount Brouncker, Chancellor to her Majesty and President to the R. Society c. concerning the spanish sembrador or new engin for ploughing, and equal sowing at sorts of grain, and harrowing, at once; By which a great quantity of seed-corn is saved, and a rich increase yearly gained; together with a description of the contrivance and uses of this engin, English't out of Spanish, and lately presented to the R. Society