91 



Fairchild Lectures. By James Hudson, Assistant Secretary 

 and Librarian — By tlie Royal Society. 

 Astronomical Observations made at the Royal Observatory at 

 Greenwich, in the months of April to September 1834. By 

 John Pond, Esq., Astronomer Royal. — By the Boyal Society, 

 London. 



The following Communications were read :— 



1. The first part of a paper on the Ruins of Babylon. By 



Dr Traill. 



2. On the application of the Hot Air Blast in the Manufac- 



ture of Cast-Iron. By Dr Clark, Aberdeen. 



The author first gives a general account of the process of manu- 

 facture of cast-iron previous to the recent improvements, stating 

 the quantities of the various materials put into the furnace, namely, 

 of the Ore, the Fuel, and the Flux. He next states the method 

 suggested first by Mr Neilson of Glasgow, and tried at the Clyde 

 Iron- Works, for increasing the product of the furnaces with the 

 same expense of materials, which consists in previously heating the 

 air thrown into the furnace, in order to accelerate combustion. 

 The method is found to produce a vast saving both in the fuel and 

 the flux, although a certain portion of fuel has, of course, to be sepa- 

 rately consumed for the purpose of heating the air, which is done 

 by causing it to traverse a recurved pipe placed within a suitable 

 furnace. During the first experiments, in 1830, the air was heated 

 to 300° Fahrenheit. In 1831, Mr Dixon of the Calder Iron- Works 

 thought of substituting raw coal for the coke which had hithei-to 

 been employed for fuel, at the same time that the air was still far- 

 ther heated to 600° Fahrenheit, and with complete success. The 

 result is, that three times as much iron is now made by the use of a 

 given tveigJu of coal as fminerly. The foUo^ving are the results of 

 the experiments made at the Clyde Iron- Works. 



In 1829, 111 tons of iron were produced from 403 of coke, or 888 of coal. 



1830, 162 376 . 886 



1831, 245 .554 



Dr Clark endeavours to point out the source of advantage thus 

 obtained, from the enormous quantity of air which is thrown into a 

 fm'nace in full action, which is not less than six tons weight in a 

 minute, and which, therefore, must exercise the most important 

 influence upon the mean temperature of the furnace. 



