The American vineyards are by no means free from the phylloxera. On the contrary, they are full of this insect, but the vines do not lose their hardiness in consequence. They flourish in spite of their enemy. THE SUN'S HEAT. Prof. Langley of the Allegheny observatory has made a direct comparison between the heat of the sun and that of the flame in the mouth of a Bessemer steel convertor. Estimates of the sun's temperature probably vary among themselves more than any other attempts at scientific knowledge, ranging from 10,000,000 down to 1,500 deg. We have already published in this Miscellany some late French determinations which place it below 2,000 deg. C. Prof. Langley's choice of a standard is excellent. The flame of the Bessemer convertor results from the burning of carbon, silicon, iron, and manganese within the vessels, the result of using this once novel fuel being a heat so great that the most refractory iron or steel is melted to thin fluidity and so much excess of heat imparted, that the mass will remain fluid, without further heat, a considerable time. The temperature of the flame is not known, though 4,000 or 5,000 deg. Fahr. has been suggested as an approximation. This does not vitiate Prof. Langley's experiment, for he used it merely as one of the most powerful artificial sources of light obtainable. His method was to compare its light with that of the sun by an arrangement that resembled a camera obscura, the light from the sun and the flame being repeatedly superposed upon each other. The arrangement worked admirably, and the observer was able to note the spots on the sun. He found that the intensely hot flame was like a dark spot compared to the sun's light and that the latter must be at least 2,168 times hotter than the flame. This carries the result in favor of the largest estimates. The flame of the convertor is not so hot as the melted steel from which it comes, but it offers better opportunities for observation. The steel itself as it was poured from the convertor was found to be not more than one-sixty-fourth as hot as the sun. DEAF MUTES IN POLAND.