In a review of the progress of aerial navigation, M. Octave Chanute says that the best shaped navigable balloon yet constructed was that which was made by MM. Krebbs and Renaud of the French War Department as long ago as 1885, and he thinks that this flying machine was superior in most respects, save that of motor equipment, to the well-known balloons of M. Santos Dumont, which have been built since. He also believes that better results than have hitherto been attained would have been reached by the Lebaudy airship had it not been destroyed; and the construction by the Lebaudys of another airship on the same line is therefore, an event of considerable interest. M. Chanute has no doubt that it is the improvement of the motor which is, and will be, the largest factor in the coming flying-machine, and this factor will apply with equal force to the airships of Santos Dumont, Le-baudy and Barton, or the aeroplanes of Prof. Langley or the Brothers Wright. In a general forecast of the flying-machine's future, he remarks: "The machines will eventually be fast, but they are not to be thought of as commercial carriers. To say nothing of the danger, the sizes must remain small and the passengers few, because the weight will for the same design, increase as the square. It is true that when higher speeds become safe it will require fewer square feet of surface to carry a man, and that the dimensions will actually decrease; but this will not be enough to carry much greater extraneous loads, such as a store of explosives or big guns to shoot them. The power re-quired will always be great - say something like 1 h. p. to every hundred pounds of weight, and hence fuel cannot be carried for long single journeys. The North Pole and the interior of Sahara may preserve their secrets a while longer."

Postmaster-General Wynne and Baron Moncheur, the Belgian minister, signed a parcels post treaty between the United States and Belgium on November 10. Under this treaty the parcels are restrictea to four pounds and six ounces each and fifty dollars in value. It is the third parcels post treaty negotiated between this country and European countries, and the twenty-sixth with any government, most of the existing treaties being with South and Central America. The present treaty will go into effect February 1. If we can have such postal facilities with foreign countries, is it not about time for the same service at borne?

A recent study of the qualities which gasoline ought to possess for advantageous employment in automo-mobiles has reached the following results. It should be very limpid, possessing a density of 0.680 to 0.590 specific gravity and perfect homogenity. It should also have a low flashing point. The flashing point of American oils varies from 73° to 110° Fahr. It should not be forgotten that a motor employing oils having a low flashing point will work better than if using the higher. This quantity must be kept in view in the use of petroleum oils in motors.

Among the more notable recent German inventions in the field of applied science is an electric resistance material for heating purposes, to which the name of "kryptol " has been given. The exact method of its preparation is not disclosed by the patent specification, but it is a mixture of graphite, carborundum and clay, and is made in four grades of coarseness. The property of kryptol upon which its efficiency depends is the fact that it offers to an electric current the requisite degree of resistance to generate a high degree of heat without destruction to its own substance. In its application to a cooking stove kryptol is sprinkled over an earthenware plate, and upon the current being switched on it readily generates sufficient heat to boil a kettle of water in three or four minutes.