|Weldon's Practical Needlework no. 338, 1914|
There are two patterns that use "Peacock" Giant Wool and "bone needles No. 3". If this is the same as a standard British size 3, it would be 6.5mm., but as the standard knitting needle sizes are based on wire thicknesses, I'm not sure whether they would apply to bone needles. The patterns don't give a tension, so that's not helpful, but it is clear from the patterns and the illustrations that Giant Wool was very thick (as you would expect from the name).
|Lady's Waistcoat in Giant Wool|
The first pattern is for a lady's waistcoat - a very practical garment "to wear under a big coat for motoring, driving, etc." I think that in 1914 driving was intending to mean riding in a carriage, so that motoring and driving were different activities - but both potentially involving exposure to bad weather. The back has only 34 stitches, increasing to 40 at the underarms, so even allowing for women being smaller in 1914, it is clear that it must be knitted in very thick yarn on very big needles.
|Lady's Hood in Giant Wool|
The waistcoat is not intended to be on view - just as well, because the increases up the front are not very tidy. The other pattern is much more decorative, although also functional. The instructions say that it can be "either an evening hood or a motor hood. For the former it can be left just as it is knitted, fairly loose around the top of the head, and it will not crush the hair." (Women's hair-styles were big in 1914, so hats had to be roomy.) "For a motor hood it will be necessary to line it with leather - just ordinary wash leather - to make it wind-proof."
Motoring evidently required a whole new wardrobe to protect both drivers and passengers from the elements. The illustration shows the hood made to fasten closely round the neck for motoring - the instructions says that for an evening hood, it could be made to fasten differently, so that one end of the neck piece trails like a scarf (which probably makes more sense if you actually knit it).
The company that made Giant Wool, Faudel's, has long since disappeared, and I don't think that other spinners made such thick yarn until the 1930s. Perhaps it did not catch on.