Pennsylvania, colonial and federal : a history, 1608-1903 . he binding materialsused in the masonry. There was little improvement in the character of mortar usedbefore the middle of the fifteenth century. Stone and brick con-structions still had to be repointed with new mortar every few-years, and chimneys not infrequently rebuilt. Even at the timementioned the new discovery claimed to have been made by aFrenchman was not of great value. His petition to the king wasbased upon his alleged discovery that the way to make the perfectmortar was to take the lime hot from the kiln and at once incor-p
Pennsylvania, colonial and federal : a history, 1608-1903 . he binding materialsused in the masonry. There was little improvement in the character of mortar usedbefore the middle of the fifteenth century. Stone and brick con-structions still had to be repointed with new mortar every few-years, and chimneys not infrequently rebuilt. Even at the timementioned the new discovery claimed to have been made by aFrenchman was not of great value. His petition to the king wasbased upon his alleged discovery that the way to make the perfectmortar was to take the lime hot from the kiln and at once incor-porate it with sand and water, instead of letting the lime andsand slake together for months, as was the old practice. Nothingpractical came of this discover^, and so it was not until about thebeginning of the last centurv that the first real progress was the great Smeaton, builder of the famous Fddystone light-house, facing the problem of erecting his massive foundationsdeep under water, made the discovery of hydraulic cement, or 460 nzsz zszn ^. 2S les: Henry ?k[artyn Hoyt Teacher; soldier in Civil War and musteredout with rank of brigadier-general; additionallaw judge courts of Luzerne County, 186-;governor, i879-:883 Natural Resources ln-(lraulic limestone mortar. Durirg his mimeroiis experimentslie learned that the theory of the ancients that the harder the hme-stone burned, tlie harder tlie cement, was incorrect. He foundthat the softer stones, those that contained a fair amoiuit of argil-laceous substances, or cla}^, gave better results, and he establishedthe principle that a limestone containing (»ne-fifth to one-fourthresidue when dissolved in hydrochloric acid, would set imderwater. To such stones he ga\e the title of hydraulic limestones,and from the [)rinciple laid d(jwn by him come the two great defi-nitions of what are now known as the natural. and the artificial(Portland) cements of commerce. Smeaton was not a financialgainer through his discovery, and
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