nd experimenting with the apparatus are Messrs. W. H. Leslie, L. E.
Emmes, F. L. Dorn, C. F. Clark, F. A. Renshaw, H. A. Stevens, Jr., Miss
H. Sherman, and Miss A. Johnson.

The numerous drawings were made by Mr. E. H. Metcalf, of our staff.

BOSTON, MASSACHUSETTS,
_August 10, 1909._

CONTENTS.

PAGE

Introduction 1

Calorimeter laboratory 3
General plan of calorimeter laboratory 3
Heating and ventilating 7

The calorimeter 10
Fundamental principles of the apparatus 10
The calorimeter chamber 11
General construction 14
Prevention of radiation 17
The thermo-electric elements 19
Interior of the calorimeter 20
Heat-absorbing circuit 22
Thermometers 26
Mercurial thermometers 26
Electric-resistance thermometers 28
Air-thermometers 28
Wall thermometers 29
Electrical rectal thermometer 29
Electric-resistance thermometers for the water-current 29
Observer's table 31
Connections to thermal-junction systems 33
Rheostat for heating 34
Wheatstone bridges 34
Galvanometer 35
Resistance for heating coils 35
Temperature recorder 36
Fundamental principle of the apparatus 38
The galvanometer 39
The creeper 40
The clock