The Pennsylvania Railroad is now rapidly complet ing portions of the vast scale of improvements it en tered upon a few years ago. Even yet many people do not appreciate the heroic character of the work undertaken, but the company is already beginning to reap its reward in earnings and improved service, both freight and passenger. An important link in this great chain of better ment is the prac tical making over of that section of the main line of the Philadelphia, Baltimore Washington Rail road centering at Havre de Grace, Md., at the mouth of the Susque hanna River, and extending about 5% miles, that is, as far north as Principio and as far south as Oak-ington. The principal feature of these improvements is a new steel and masonry bridge, about a mile long, over the Susque hanna River at Havre de Grace, Md. This bridge was built in fast time, and embodies many interesting fea tures. The other changes were in line with the estab lished policy of the Pennsylvania Railroad to elimin ate grade crossings, reduce grades, and straighten out curves, wherever possible. These improvements mark another step in the plans of the company event ually to reduce the running time between New York and Washington to four hours, without sacrificing the slightest element of safety. With this work completed, the main line of the Philadelphia, Baltimore Washington has four tracks between these stations, except over the Susquehanna Bridge, which carries two. Not a grade crossing has been left, grades are reduced, and curvature is now at a minimum. The road has been built to serve its purpose at a small cost of maintenance, for an indefi nite period of time. The improvements center in the big bridge at the mouth of the river, and which is located about 150 feet north of the old structure. The ponderous char acter of this bridge may be realized from the fact that it contains 44,369 cubic yards of masonry and 20,230,384 pounds of iron and steel. The structure consists of seventeen fixed deck spans and a through draw span 280 feet long from center to center of the rest piers. The first fixed span on each end is 196 feet 6 inches long; the remaining spans on the Havre de Grace end are each 200 feet long, and on the Perryville end they are each 260 feet long from center to center of piers. The fixed spans have a clearance of 24 feet 3 inches at mean tide, and the draw span has a clearance of 53 feet at mean tide. When opened, the draw presents a clear opening of 100 feet, on either side for the pass age of vessels. The bridge rests upon twenty piers of Allegheny Mountain sandstone with concrete backing and Port Deposit granite coping. They are at right angles to 363 the bridge, with the exception of the two rest piers for the draw, which are swung 14 degrees to the west, to bring them in line with the current of the river. Pier No. 1, the east abutment, was built by open cofferdam construction on rock at an elevation of 4.4 feet. Excavation for piers Nos. 2, 3, and 4 was carried on by the open cofferdam construction, and in the case of pier No. 3 a depth of —32.0 feet was reached. From the bottom of the excavations piles were driven to solid rock. In the case of No. 2 pier, 294 piles were driven until their points were at a depth of —77.0 feet. Piers Nos. 3 and 4 each rest upon 390 piles driven until the points reach ed an average depth of —110.0 and —88.0 feet respectively. Piers Nos. 5 to 16 inclusive were built on pneumatic caissons at depths oi from —22.3 to —87.6 feet. Work was started upon the piers in the summer of 1904, but not much river work was done until the ice went out in 1905. The last masonry was laid on the fender pier December 16, 1905. The fender at the draw is built of piles with a granite pier at the north end, and a timber crib filled with stone at the south end. The granite pier rests upon a caisson sunk to a depth of —44.8 feet, while the crib rests on the river bottom dredged to a depth of —30.5 feet. Erection of the steel work was begun August 10, 1905, and finish ed May 22, 1906. The draw span was erected on falsework over the fender, and swung into position May 19, 1906. Industrial Alcohol. Dr. Wiley, of the United States Department of Agriculture, in his conclusions on industrial alcohol, points out that the manufacture of alcohol on a very small scale is not likely to prove profitable. Experience has shown that attempts to manufacture sugar and other substances of a similar character on a small scale cannot compete with simi lar manufacturing industries on a large scale. Fur thermore, any still for the distillation of spirits must be registered and conducted under the supervision of the internal revenue officers; and though no regula tions on the subject exist, the rules in regard to out put practically result in fixing the minimum size of a registered still as one making from 7 to 10 proof gal lons per day. It is thus seen that it will not be prac ticable for the farmer to operate a still on a small scale under present conditions. Moreover, the still can only be shut down by an internal revenue officer, and thus it would not be practicable to conduct a small still in a desultory manner. The still must be constructed as prescribed by law and the process con ducted in all its details according to the regulations of the internal revenue. It is evident that the farmer must be content with producing the raw materials and that he cannot look forward to becoming a practical distiller. The benefits which are to accrue from the use of I lustrial alcohol free of tax have probably been over estimated by the people at large, and especially by the farmers, but that material benefits will accrue is not a subject of doubt. These benefits will come, not suddenly but slowly, as agricultural products are more abundant, technical methods of manufacture improved, and the method of utilizing the industrial alcohol bet ter understood. Our people should not, however, be disappointed should many years elapse before the mag nitude of the product used for industrial purposes reaches the figure already attained by Germany and some of the other European nations. Of the raw materials which can be utilized for the manufacture of alcohol, Indian corn is by far the most abundant and the most promising source at the present time. The average price of potatoes must be very much decreased before raw material of this kind can come into competition with Indian corn as a source of alcohol. Promising sources which are not now utilized for the manufacture of alcohol in this country are the potato, the sweet potato, the yam, sorghum, molasses from the sugar-cane and beet-sugar factories, and the Indian-corn stalk. Waste materials of other manufacturing industries, such as those re lated to fruits and vegetables, may incidentally be uti lized for manufacturing purposes, but could not of themselves become independent sources of profitable industrial alcohol. An Aeroplane Prize Offered by tlie Auto. The offer by the SCIENTIFIC AMKKICAN of an aero plane trophy has caused much interest in Europe—so much that our esteemed Paris contemporary, Auto, has followed the example and offers a cup for aero planes. The idea is a simultaneous race, and the ma chine which covers the longest distance to be declared the winner. All the flyers would be assembled at the start, and would commence the race at a given signal. Judges would observe the distances for the finish, and two chronometers would take the total time for each machine. There would also be a number of judges placed along the course so as to see the probable point from which the flight took place. It is probable that the leading aeroplanes will be entered in the event, and it will certainly be novel to see the flyers drawn up in line.