36 ANNUAL OF SCIENTIFIC DISCOVERY. 



the whole is then watered. An immense roller is propelled by 

 steam, and moved slowly over the prepared surface. It exerts a 

 pressure of 28 tons, and the result is that in an unusually, short 

 time a firm and compact Macadamized road is formed, so smootli 

 that the liij:htest vehicles ma}' be immediately driven over it with- 

 out fear of injuring the springs. The engine works almost witli- 

 out noise, and appears to consume nearly all its own smoke." 



Daily care is required, for a while, to prevent the forming of 

 ruts ; as soon as the ruts appear they should be filled and then 

 rolled over again. This costs something, but the eventual or re- 

 sultant cost is less, both to the town authorities and those who use 

 the roads^ than is that of our present system. A smooth and even 

 surface is nearly as important on common roads as it is on the 

 railway. The science of road-making is simple enough, but our 

 people almost always fail in it. Once properly constructed and 

 drained, our common roads could be kept in good working order 

 for a tithe of what it now costs. The use of the steam roller sim- 

 plifies the matter very much, and probably before long it will be 

 freely used in nearly all our larger towns. — Scientific American. 



STREET RAILWAYS. 



Mr. Thorold read a paper, at the last meeting of the British As- 

 sociation, giving a description of an auxiliary railway invented by 

 him for the purpose of utilizing turnpike roads and highways and 

 the streets of towns. Mr. Thorold remarked that this railway 

 would only require a single rail, which he proposed should be laid 

 on one side of the road, out of the wa}' of the ordinary trafiic. An 

 arrangement of grooved wheels under the centre of the eno:ine 

 and carriages, so constructed that they will be capable of main- 

 taining their grip upon curves of 20 feet radius, gives the vehicles 

 the power of turning corners with the greatest facility. The 

 inventor thinks his principle peculiarl}' adapted to locomotion 

 through new countries, and for passing through ravines, or up 

 and down the sides of mountains up any gradient not exceeding 1 

 in 12. He proposed to propel the carriages by steam-traction en- 

 gines, although they might also be drawn by elephants, horses, 

 or other beasts of burden. The adhesion of the traction wheels 

 could be regulated to any weight, and b}' the application of a 

 special apparatus the engine might be made to lift the traction 

 wheels out of a soft place. The cost of the new railwaj" would be 

 about £500 per mile. 



In Bright's patent tramway, instead of the ordinary tramway 

 flange, the rail is inclined, an(l the wheels of the carriage are ta- 

 pered so as to fit the bevel of the rail. Among the alleged ad- 

 vantages of this method are the facilities afforded for the carriages 

 quitting the rail and again coming on to it (a portion of the wheel 

 being flat, and adapted to road travelling), and the ease with which 

 ordinary carriages may cross the road, the slight inclination of 

 which presents no serious obstruction to a vehicle. 



The invention of the application of vulcanized India-rubber to 



