Without entering into the details of this plan, for which we must refer to the paper itself, we shall content ourselves with explaining its principle. Suppose two iron reservoirs, A and B, of equal capacity, placed twenty feet apart, and connected at the top and the bottom by iron pipes, the level of both reservoirs being the same; it is obvious that water poured into one of these reservoirs will flow into the other through the connecting pipes, and that it will consequently stand at the same height in both. Let the reservoirs be thus filled above the level of the uppermost pipe, and heat be applied to the bottom of one reservoir, A; the water in this will presently be forced through the upper pipe into the reservoir, B, of water not heated; in proportion as the heated water flows out of A, through the upper pipe, the cold water will flow out of B through the lower pipe; and by this means a circulation of water heated and water to be heated will be formed, which will continue as long as the application of fire to the bottom of one reservoir is continued. When it is discontinued, the temperature of the two reservoirs and of the intermediate pipes will be the same within three or four degrees. As it is the property of heated water to part with its heat very slowly, it follows that heat will continue to be disengaged from the reservoirs and pipes long after the application of fire has ceased. In fact, when the two reservoirs are once heated, the gardener may make up his fires and retire to rest, certain that his house is sufficiently provided with heat for the night. The paper is accompanied with a plan of a vinery warmed upon this principle. [p176] _On the Recent Elucidations of early Egyptian History_. Since the commencement of the present century, the researches of philologists have ascertained that the language of ancient Egypt,—the language of the hieroglyphical inscriptions engraven on its ancient temples and monuments, and of the still existing manuscripts of the same period,—differs from the modern Egyptian or Coptic, only in the mixture in the latter of many Greek and Arabian and a smaller portion of Latin words, introduced during the successive dominion of the Greeks, the Romans, and the Arabs, and occasionally substituted for the corresponding native words. The grammatical construction of the language has remained the same at all periods of its employment: and it finally ceased to be a spoken language towards the middle of the seventeenth century, when it was replaced by the Arabian.