702 Transactions of the American Institute. 



containing about thirty-four per cent of carbonate of lime and 

 sixty-six per cent of bitumen, found at Seyssel, in France, and at 

 Val-de-Travers, in the Canton Neuchatel, in Switzerland. This 

 bituminous stone is crushed to powder by machinery, and afterward 

 heated to about one hundred and forty degrees C. It then has 

 about the consistency of molders' sand, and, on being reheated, it 

 is applied to the streets, which have first been covered with a layer 

 of concrete, made of gravel and cement. The asphalt layer, nearly 

 two inches in thickness, is first compressed by means of rams, 

 worked by hand, and then made smooth by means of different 

 rollers, the heaviest weighing four tons. In two or three hours 

 after last rolling the road is ready for use. No dust or mud is 

 made on this noiseless road. The average wear per annum on the 

 busiest streets does not exceed one twenty-fifth of an inch. 



PETROLEUM TO REMOVE SCALE IN BOILERS. 



In regard to the scientific item in relation to anti-incrustation, it 

 was stated that a little petroleum put in steam boilers would pre- 

 vent incrustation. Mr. Root stated, that such had been his obser- 

 vation, and upon being asked how it could be applied in boilers 

 when filled with water and steam, he said it could not be, but 

 it might be placed in the boiler before the water was let in, and, 

 as the boiler filled, it would sufficiently coat the iron by adhering 

 to it as it floated upon the waiter. Mr. Pepper confirmed the 

 observation of Mr. Root, and stated that petroleum would not 

 only prevent but would remove scale, and this could be done by 

 burning the kerosene in the boiler. Mr. Callow said that he 

 was fearful that scale removed by burning would cause the boiler 

 to leak at the joints, and that, with the apparent benefit, much 

 subsequent injury might ensue. 



IMPROVED CANAL BOAT. 



Mr. William Frick, of Chester, Pa., exhibited a model and 

 explained his method of operating sectional canal boats. The boat 

 is made in two sections, which are hinged together one in advance 

 of the other. This rear section is supplied with a rudder, and can 

 be steered similar to an ordinary boat; but the great improvement 

 consists in using the rear section as the means of guiding the lead- 

 ing one. This is accomplished by means of a steering wheel placed 

 in the bow of the rear section, and so arranged, that when it is 

 turned as in the act of steering, the bow of the boat or section to 



