The illustration is from a company started in 1846 to sell hand knitted underwear. They did that for many years, moved to London in 1892 and there still was a Mr Bill in 1964 at the time of the prining of this book!
They sold Shetland knit underwear as the Shetland yarn was very soft, smooth and light.
W Bill was written up in Sylvia’s Home Journal in 1881 and this helped promote them, no doubt spurring on their big city move and to persue wholesale and also the sale of outer garments in 1910.
I do remember wool being used for baby clothes when I was a kid in England in the ’50’s. Were kids hardier or was the wool softer? More investigations needed… how exciting, I’d love to get my hands on samples from early in the last century.