MECHANICS AND USEFUL ARTS. 53 



dent was entirely owing to the faulty construction of the shells which were 

 at first used. They were made in two parts, and welded together, and the 

 weld being- occasionally imperfect, the flame of the explosion penetrated 

 into the shell, which burst in, and of course shattered the gun. Shells made 

 in one piece were at once substituted, and nothing of the sort has since 

 occurred. 



In regard to the effect of twist in rifled guns, every artillerist seems to 

 have his own ideas as to the degree of it to be given, varying from Mr. Had- 

 dan's one turn in forty feet to Mr. Whitworth's one turn in forty inches; 

 but not one of them takes the trouble to give his reasons for selecting the 

 precise pitch which he has decided to adopt. Mr. Haddan, indeed, believes 

 that a very rapid tAvist is likely to burst the gun; and Mr. Whitworth says 

 vaguely that it is very desirable to give a very rapid rotation to the projec- 

 tile; but neither one nor the other cites either facts or theories in support of 

 his view. Mr. W. B. Adams regards rifling merely as a device for correct- 

 ing the defects of badly constructed projectiles; and as it involves a consid- 

 erable waste of propelling power, he hopes before long to see it dispensed 

 with altogether, by the employment of more accurately-made shot. 



Perhaps the most obvious and striking conclusion that is deducible from 

 the whole of this discussion is, that the science of artillery is as yet in its 

 infancy. There is not a single point of importance on which the most 

 opposite opinions are not held by the most competent authorities. To spec- 

 ulate on the causes which have led to this extraordinary neglect on matters 

 of such vital import would be a task more easy than profitable. 



SCIENCE IN THE BATTLE-FIELD. 



The following is an abstract of a lecture recently delivered before the 

 Royal Institution, London, by Mr. F. Abel, Director of the chemical establish- 

 ment of the War Department of Great Britain, " On the recent Applications 

 of Science in Reference to the Efficiency and Welfare of Military Forces." 



One of the most important subjects in connection with military equipment, 

 and one which has recently received a very large share of general attention, 

 relates to the changes which have gradually been effected in the nature of 

 material, and the principles of construction, applied to the production of 

 cannon Until very recently, the materials used for cannon have been only 

 of two kinds east iron and bronze, or, rather, the alloy of copper and tin, 

 known as gun-metal. Of these, the latter is by far the most ancient. Guns 

 were cast of bronze in France and Germany about 1370, and from that period 

 until the close of the fifteenth century this material gradually replaced 

 wrought iron, of which guns were constructed in the first instance. An 

 examination of such iron guns of early date as are still in existence such 

 as the Mons Meg, of Scotland, the great gun of Ghent, and others shows 

 that the principles involved in their general construction are precisely those 

 which have just been most successfully applied to the production of wrought 

 iron rifled guns in this country. Those ancient guns were built up of stave- 

 bars, arranged longitudinally, upon which wrought-iron rings were shrunk. 

 The very imperfect nature of those structures, arising from the primitive 

 condition of mechanical and metallurgic appliances at that early period, 

 rendered their durability exceedingly uncertain; and it is therefore not 

 surprising to find that compound guns of this class were gradually replaced 

 by cannon cast in one piece. Even the great expense of bronze, as com- 



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