WW1 bombs with a white cross on them suggests that they contained lacrymatory gases that produced temporary blindness. Liberation of small quantities of a gas of this type made it impossible for the soldiers to carry on without wearing a mask and exposed them to other, more dangerous, gases such as Phosgene. Practically all of the long list of lacrymators had a bromine base.
I have a website devoted to WW1 medical history and you will find descriptions of all WW1 gases at: http://www.vlib.us/medical/gaswar/gas.htm
Regards from Sydney,
Geoffrey
I have a website devoted to WW1 medical history and you will find descriptions of all WW1 gases at: http://www.vlib.us/medical/gaswar/gas.htm
Regards from Sydney,
Geoffrey