weight of fibers per unit area therein completely and substantially independently of the formation of every other predetermined region having a different weight of fibers per unit area therein referring to fig1 and 17a the secondary fibrous pad 286 and the middle region 290 of the main fibrous pad are formed as the transversely aligned main and secondary pad receiving compartments pass over the vacuum box 224 the vacuum box 224 is masked to prevent the passage of air through the forward and rearward end sections 301 and 303 respectively of each of the main pad receiving compartments 296 some minor dusting of fibers occurs in the forward and rearward end sections 301 and 303 of each main pad receiving compartment as it passes over the vacuum box 224 however as explained earlier in this application this dusting of fibers has substantially little if any effect on the resistance to air flow through said forward and rearward end sections of the pad receiving compartments during the subsequent formation of said forward and rearward end regions 288 and 292 respectively of the main fibrous pad 284 referring to fig1 and 17b the middle region 290 of the main fibrous pad 284 is formed in a middle section 305 of each main pad receiving compartment 296 as each of said compartments 296 pass over the vacuum box 226 the vacuum box 226 is masked to prevent the passage of air through all sections of the main and secondary pad receiving compartments except the middle section.