Those light bulbs!

An addendum to Mr Agius Cesareo's observations on Christmas tree bulbs (The Sunday Times, December 19). Although his arithmetic is elegant and his logic faultless, there are also some physical considerations that should not be overlooked.

In fact, if one were to take off 14 bulbs from the Christmas tree, the total resistance of the bulbs would go down by 14%, increasing the current flow by 6.78% and the power consumption (and hence the running cost) by a staggering 16%. There would therefore not be any cost saving by undergoing this exercise.

As a consequence of taking off these 14 light bulbs, the Christmas tree would also shine more brightly. However, since you can't have something for nothing, the increase in current would overdrive the light bulbs thus reducing their lifetime thereby increasing the already onerous maintenance costs of the Christmas tree.

Therefore, should Mrs Gonzi (and not forgetting all the others with the same problem) wish to restore her Christmas tree bulb electricity bill to the level prior to the 17% levy, she should increase the number of bulbs by 17 to 117 instead of reducing them by 14 to 86.