Elements of the graph are shown from an axis through 0 and at right angles to OX.
The graph will then be made up of a succession of parallel lines.
The assemblage of ordinates NP is then the graph of Y.
If we assume that the bolograph of solar energy is simply a graph of amorphous radiation from an ideal radiator, so that the con- Temperature stants cl, c 2, of Planck's formula determined terrestrially apply to it, the hyperbola of maximum intensity is XO = 2, 921 X 10 7; and as the sun's maximum intensity occurs for about X =4900, we find the absolute temperature to be 5960° abs.
If, for instance, the graph were a trapezium, the calculation of the area would be equivalent to finding the integral, from x=a to x=b, of an expression of the form px+q.