Non-fiction: Gelignite (Blasting gelatine)

Overview
Alfred Nobel's gelignite, patented in 1875 and often called blasting gelatin or gelatine, represented a significant advance in high explosives. It combined the powerful liquid explosive nitroglycerin with a gelatinizing agent derived from nitrocellulose to produce a cohesive, malleable substance that preserved the energetic properties of nitroglycerin while improving handling and performance. The invention quickly found practical application in mining, tunneling, quarrying and other heavy engineering tasks where controlled, reliable blasting was required.

Composition and Chemistry
Gelignite is fundamentally a combination of nitroglycerin and nitrocellulose, the latter serving as a colloidal binder that swells and gels the nitroglycerin into a viscoelastic mass. Small proportions of stabilizers, thickeners and inert fillers were often added to tune consistency and sensitivity. The chemistry rests on the energetic nitrate esters of both components: nitroglycerin supplies a high detonation velocity and brisance, while nitrocellulose contributes additional oxidizing equivalence and structural coherence to the mixture.

Manufacture and Physical Properties
Production involved careful dissolution and mixing to ensure homogeneous distribution of nitroglycerin within the nitrocellulose matrix, often using volatile organic solvents that were later removed to yield a plastic, gelatinous product. The finished material could be extruded, cast into cartridges, or molded to fit boreholes. Gelignite was typically more flexible and waterproof compared with older porous dynamites, retaining its form in wet conditions and tolerating rough handling better than neat nitroglycerin.

Performance and Advantages
The principal advantage of gelignite was its combination of high explosive power with improved safety and convenience. It achieved detonation velocities and brisance close to those of pure nitroglycerin while being less prone to accidental initiation by shock and friction. Its gelatinous consistency allowed tighter coupling to rock faces and explosive charges that maximized energy transfer, reducing the quantity of explosive required for many jobs. Waterproofing made it suitable for wet boreholes and marine work where ordinary dynamite could fail.

Safety, Handling, and Stability
Although safer to handle than naked nitroglycerin, gelignite was not without hazards. It could exude nitroglycerin over time, particularly under temperature fluctuations, and aged material could become more sensitive. Freezing and thawing cycles, prolonged storage, or exposure to incompatible chemicals could increase risk. These realities led to evolving manufacturing controls, storage protocols and later regulatory frameworks designed to mitigate accidental detonation and environmental contamination.

Applications and Commercial Impact
The introduction of gelignite broadened the practical use of high explosives in civil engineering and mining, accelerating tunneling projects, rail and road construction, and quarrying. Contractors appreciated its moldability and the reduced need for complex tamping or specialized cartridges. Commercially, gelignite strengthened the explosives industry and expanded markets for Nobel's enterprises, contributing to a shift from ad hoc use of nitrated compounds to standardized industrial explosives and safety practices.

Legacy and Historical Significance
Gelignite stands as a transitional technology between early nitroglycerin-based mixtures and later modern plastic explosives. It illustrated the value of combining energetic performance with physicochemical control over form and handling. The invention influenced subsequent formulations and safety standards and played a role in the broader industrialization of blasting techniques. It also forms part of Alfred Nobel's technological legacy, which included parallel advances that financed scientific patronage and the eventual establishment of the Nobel Prizes.