White clouds, white clouds, up so highI can't find a reference to the poem anywhere else but this poster, and since the poster is unsigned, the poem is too.
White clouds, white clouds, in the sky
Clouds so white and sky so blue:
How I love to look at you.
Soapsuds, soapsuds, in my hair
Soapsuds, soapsuds, white and fair:
Tell me mother, tell me true,
Are the clouds just soapsuds too?