Sul calore di ignizione nelle misure in bomba calorimetrica

Riassunto

Si descrive un metodo semplice e preciso che consente la misura del calore di ignizione di volta in volta nelle determinazioni di precisione del calore di combustione in bomba calorimetrica e si comunicano alcune osservazioni sperimentali fatte con questo metodo.

Summary

A method is described for the measurement of the «ignition energy» in bomb calorimetry. A big storage battery is directly connected, for the ignition, to the fuse wire, so as to ensure a constant potential difference at its leads. A ballistic galvanometer, suitably shunted (shunt less than 0.01 ohm), is only inserted to measureq=∫idt, whence the ignition energy$Q = \frac{l}{J}Eq$ follows. The method enablesQ to be measured at every single combustion, without giving rise to any of the objections of the methods previously used; it has proved to be simple and reliable. Some experimental observations are added.