108 



REPORT 1855. 



the trunnions slabbed longitudinally and ringed as shown. Mr. Handyside 

 adopted this method in order to make use of wrought iron, as he conceives 

 that they could not be made of it entire. He was led to this plan by having 

 successfully made in this way an hydraulic press cylinder after a cast one 

 had broken. The forged one has stood for six years and is still sound. 

 Others made since in the same way have been equally successful. 



It is questionable whether any built gun can long resist the violence of 

 the explosion, and we believe that wrought iron is not the best material for 

 heavy ordnance. Nevertheless, in our opinion, Mr. Handyside's gun and 

 mortar are constructed on a better principle than most we have yet seen. 

 Extracts from a letter from Mr. Cochran addressed to Mr. Fairbairn. 



Without date. 



Mr. Cochran attributes the failures of ordnance of the present day to the 

 inferiority of the metal and to the defective manner of casting. He would 

 obviate the first by the use of iron from the Acadian mines of Nova Scotia, 

 which he states to be equal if not superior to the celebrated Swedish metal, 



Fig. 7. 



^^^»^^^^^^^^ 



Gun as now adopted in the United States — from a drawing sent by Mr. Cochran. 

 We think it would be improved if the metal were filled up as far as the dotted lines a a. 



and is used extensively by the Government of the United States for artillery. 

 The defective mode of casting he would remedy by the use of the water 

 core which he has invented. He encloses the ordinary mould in a case of 

 non-conducting materials so thick as entirely to prevent the passage of heat 

 from the exterior of the casting. To accelerate the cooling on the interior 

 of the castiny be uses a hollow core through which he can draw a stream of 

 water or current of air at pleasure. 



On Typical Objects in Natural History. 



[^Circular.'] 



Hitcham, Bildeston, Suffolk, 

 June 1855. 



Dear Sir, 



To secure materials for a Report called for by the Natural History Section ^ 

 of the British Association " On a Typical Series of Objects in Natural 

 History adapted to local Museums," I would thank the Members of the 

 Committee to furnish me with the names and addresses of Naturalists whom 

 they know to have paid special attention to particular groups in either the 

 animal, vegetable, or mineral kingdoms. I will then request these parties, 

 as I ROW do the Members of the Committee, to send me their opinion of 



