refutation of the claim [A lamp kept in windless place does not shake.” Bhagvad Gita: 6: 19 Scientifically this is not true.]

Original verse with translation
yathā dīpo nivāta-stho neńgate sopamā smṛtā
yogino yata-cittasya yuñjato yogam ātmanaḥ

yathā — as; dīpaḥ — a lamp; nivāta-sthaḥ — in a place without wind; na — does not; ińgate — waver; sā — this; upamā — comparison; smṛtā — is considered; yoginaḥ — of the yogī; yata-cittasya — whose mind is controlled; yuñjataḥ — constantly engaged; yogam — in meditation; ātmanaḥ — on transcendence.

As a lamp in a windless place does not waver, so the transcendentalist, whose mind is controlled, remains always steady in his meditation on the transcendent self.

Refutation
Windless does not necessarily mean that there is no air (vaccum). Thus there shouldn't be any problem in lighting a lamp. All it means that flame of the lighted lamp won't waver as there is no wind, or moving air.Dictionary meaning, resembles the meaning of "windless" to "Having no wind; calm".