NOTES, 



255 



The Pneamatic Dispatch. — The following 

 description of the London " Pneumatic Dis- 

 patch," for the conveyance of small par- 

 cels of goods from place to place, we take 

 from the 2'imes: 



" The pneumatic tube extends from the 

 London and Northwestern Railway Station 

 at Euston Square, to the General Post-Office 

 in St. Martin's-le-Grand. The central sta- 

 tion is in Holborn, where is also the ma- 

 chinery for effecting the transit of the trains. 

 Here the tube is divided, so that in effect 

 there are two tubes opening into the station, 

 one from Euston to Eolborn, and the other 

 from the Post-Office. The length of the 

 tube between Holborn and Euston is exactly 

 a mile and three-quarters. The tube is of 

 a flattened, horseshoe section, 6 feet wide 

 and 4 feet 6 inches high at the centre, hav- 

 ing a sectional area of 17 square feet. The 

 straight portions of the line are formed of 

 a continuous cast-iron tube, the curved 

 lengths being constructed in brick-work, 

 with a facing of cement. The gradients are 

 easyj the two chief are 1 in 45 and 1 in 

 60 ; the sharpest curve is that near the 

 Holborn station, which is 70 feet radius. 

 The tube between Holborn and the Post- 

 Office is 1,658 yards in length, and is of the 

 same section, and similarly constructed to 

 the first length. Two gradients of 1 in 15 

 occur on the Post-Office section, but this 

 steep inclination is in no way inimical to 

 the working of the system. The Holborn 

 station is situated at right angles to the line 

 of the tubes, which are therefore turned 

 toward the station into which each opens. 

 All through-trains, therefore, have to reverse 

 there, and this is effected in a simple man- 

 ner by a self-acting arrangement. 



"The wagons, or carriers, as they are 

 termed, weigh 22 cwt., are 10 feet 4 inches 

 in length, and have a transverse contour 

 conforming to that of the tube. They are, 

 however, of a slightly smaller area than the 

 tube itself, the difference — about an inch all 

 round — being occupied by a flange of India- 

 rubber, which causes the carrier to fit the 

 tube exactly, and so to form a piston upon 

 which the air acts. The machinery for pro- 

 pelling the carriers consists of a steam- 

 engine having a pair of 24-inch cylinders 

 with 20-inch stroke. This engine drives a 

 fan 22 feet 6 inches in diameter, and the two 



are geared together in such a manner that 

 one revolution of the former gives two of 

 latter. The trains are drawn from Euston 

 and the Post-Office by exhaustion, and are 

 propelled to those points by pressure. The 

 working of the fan, however, is not reversed 

 to suit these constantly-varying conditions ; 

 it works continuously, the alternate action 

 of pressure and exhaustion being governed 

 by valves." 



NOTES. . 



Dr. James McNaughton, President of the 

 Albany Medical College, and Professor of the 

 Practice of Medicine, is supposed to be the 

 oldest medical lecturer now in active ser- 

 vice. He has delivered fifty-three annual 

 courses of lectures, and, during this half- 

 century of work, has not missed a dozen 

 lectures or been confined to the house a 

 week by sickness. He is seventy-seven 

 years old, and is hale and active. 



The white-willow, it is said, has been 

 used very successfully in Iowa for fencing. 

 C. B. Mendenhall, of Marshall County, has 

 about thirteen miles of white-willow fence, 

 of from three to seven years' growth, of 

 which above half will turn cattle. He has 

 also a grove of white-willows, set out about 

 six years ago, which is considered to be 

 worth about $500 per acre. 



A Western paper reports that a spaniel, 

 named Curly, performs the duties of mail- 

 carrier between Lake of the Woods, Da- 

 kota, and the Minnesota line, twelve miles 

 distant. Letters and papers are placed in 

 a sack and tied about the dog's neck ; he is 

 told to go, and never fails to reach his des- 

 tination. On his arrival, the mail is over- 

 hauled, the dog is treated to a good dinner, 

 and started back again. 



Philadelphia possesses a very energetic 

 Zoological Society of about 500 members. 

 Thirty-five acres of ground in Fairmount 

 Park have been assigned to them for a zoo- 

 logical garden, though for the present they 

 will occupy but ten acres. Within the last 

 six months the society has laid vulcanite 

 walks through the garden, built a monkey- 

 house, and made other provision for a large 

 number of beasts and birds from all parts 

 of the world. A small collection has already 

 been made, which will this summer be added 

 to by importations from Africa, Asia, and 

 Australia. There will be a large aquarium, 

 and it is intended to institute courses of 

 popular lectures on Natural History. 



At a meeting of the Philadelphia Acad- 

 emy of Sciences, Mr. Meehan exhibited a 



