ANALYSIS OF PEECEDING PAPER, 



CHAPTER I.— Introduction. 



SECTIONS. PAGE. 



1, 2 Introductory, 141 



3 Formula for resistance of cylinders to internal pressure, 142 



4 Formula for work done by the charge, 1 43 



5 Increment of strain in relation to caliber, 143 



6 Accidents by shell guns ; objects of the work, 144 



CHAPTER II Directions of Fracture in Borst Guns. 



7 Usual directions of fracture, 145 



8 Three principal circumstances attendant upon 14ti 



CHAPTER III. — Causes ; Molecular Constitution op Crystalline Bodes. 



9 General law of molecular aggregation of crystalline solids in consolidating, . . . 147 



10 Examples; line of direction of the principal axes of the crystals in mass in cooling, 147 

 11, 12 Examples — converse by law of aggregation when the solid is heated, .... 148 



13, 14, 15 Examples under other conditions, 148 



CHAPTER IV". — Molecular Constitution of Cast-Iron. 



16 In cast-iron the principal axes tend to place themselves perpendicular to the bound- 



ing surfaces, 149 



17 Causes upon which the development of the crystals depend 149 



18 Examples of crystalline arrangement on the large scale; Reference to Plate II., . 150 



19 Effects on internal structure of sudden changes of external form, 151 



20,21 Existence of "Planes of Weakness;" Examples, 151 



22 Injudicious forms and ornaments of guns, 152 



CHAPTER v. — Physical Conditions induced in Moulding and Casting. 



23 Conditions affecting homogeneity, contraction, slow or rapid cooling, fluid pressure, 152 



24 Relation of size of crystal to the mass, 153 



25 Erroneous conclusions as to effects of repeated meltings on cast-iron, 153 



26 Difference of size of crystal produced under conditions of casting and metal in all 



respects alike, 154 



27 The size of crystal developed depends upon the time, the regularity upon the 



uniformity of cooling, 154 



28 And, for given make and mass, upon the elevated temperature of the metal, and 



the time of its cooling, 154 



29 Analogies and confirmations from Mr. Bolley's Researches 155 



30 Practical deductions, 156 



VOL. xxni. 3 K 



