To withstand the chemical action of the gases, the " calorimetric bomb " is lined either with platinum, as in Berthelot's apparatus, or with porcelain, as in Mahler's.
The thermochemical magnitude which is universally determined for organic compounds is the heat of combustion, usually by means of the calorimetric bomb.
Fuel oil is submitted to certain of the foregoing tests and in addition the calorimetric value is determined.
If the heat of solution be measured in a calorimeter, no work is done, so that, if we call this calorimetric heat of solution L, the two quantities are connected by the relation L = X+P(v - v).
Calorimetric Bar Method.
No calorimetric observations are required, but the results are obtained in terms of the thermal capacity of unit volume c, and the measurements give the diffusivity klc, instead of the calorimetric conductivity k.
The quantity of heat absorbed by the stratum (x' x") in the interval considered can also be expressed in terms of the calorimetric conductivity k.
This method is the most generally convenient and most readily applicable of calorimetric methods, but it is not always the most accurate, for various reasons.
Analogous difficulties arise in the application of other calorimetric methods.
A is the calorimetric tube, B the air-jacket and L the gauge.
J Amin And Amaury, And Of Many Other Experimentalists Who Succeeded Regnault, Appeared To Indicate Much Larger Rates Of Increase Than He Had Found, But There Can Be Little Doubt That The Discrepancies Of Their Results, Which Often Exceeded 5%, Were Due To Lack Of Appreciation Of The Difficulties Of Calorimetric Measurements.
The Conditions Of Use Of A Mercury Thermometer In A Calorimetric Experiment Are Necessarily Different From ' Those Under Which Its Corrections Are Determined, And This Difference Must Inevitably Give Rise To Constant Errors In Practical Work.
The Specific Heat At 4° Could Be Accurately Determined At The Mean Over The Range O° To 8° Keeping The Jacket At O° C. But The Change Appears To Be Rather Rapid Near O°, The Temperature Is Inconveniently Low For Ordinary Calorimetric Work, And The Unit At 4° Would Be So Much Larger Than The Specific Heat At Ordinary Temperatures That Nearly All Experiments Would Require Reduction.
The former investigates essentially general properties, such as the weight and density, the relation between pressure, volume and temperature (piezometric and thermometric properties), calorimetric properties, diffusion, viscosity, electrical and thermal conductivity, &c., and generally properties independent of composition.
The calorimetric data are generally the most deficient and difficult to secure.
The Range 15° To 25° Would Be Much More Convenient From This Point Of View, And A Mean Temperature Of 20° Is Probably Nearest The Average Of Accurate Calorimetric Work.