Calc War of the Worlds (original) - The Heat Ray

War of the Worlds said:

Then suddenly we saw a rush of smoke far away up the river, a puff of smoke that jerked up into the air and hung; and forthwith the ground heaved under foot and a heavy explosion shook the air, smashing two or three windows in the houses near, and leaving us astonished.

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The Martians Heat Ray shakes the ground enough to break windows. It does this again later.

War of the Worlds said:

Then, after an interminable time, as it seemed to us, crouching and peering through the hedge, came a sound like the distant concussion of a gun. Another nearer, and then another. And then the Martian beside us raised his tube on high and discharged it, gunwise, with a heavy report that made the ground heave. The one towards Staines answered him. There was no flash, no smoke, simply that loaded detonation.

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We can determine a minimum distance from the first one.

War of the Worlds said:

Then, as the Martian towered overhead scarcely a couple of hundred yards away, I flung myself forward under the surface.

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200 yards is equal to 182.88m. Breaking windows matches a scale VI on the mercalli scale, which translates to 5 on the richter scale.
Playing around with the impact calculator until I got the right results, we get 1.63 x 10^16 joules for 183.00km. That's a lot more than the actual range, so we have to divide it to get our results proper.

183000/182.88 = 1000.65617

E = 1.63 x 10^16/1000.65617
= 1.62893114e13 joules

Then you divide it by 10000.

E = 1.62893114e13/10000
= 1628931140 joules
= 0.3893238862333 tons of TNT

Final Results
The Martians Heat Ray = 0.389 tons of TNT