Deliberation, premeditation and wilfulness may be inferred from the proof of such facts and circumstances as will furnish a reasonable foundation for such a conclusion. (People v. Eggers, 30 Cal.2d 676, 685-686 [185 P.2d 1]; People v. Cole, 47 Cal.2d 99, 106 [301 P.2d 854, 56 A.L.R.2d 1435].) [7] It is not {Page 178 Cal.App.2d 731} for this court to weigh the probabilities.