§ Mr. R. MORRISONasked the Minister of Health whether he has received any explanation from the Inter-Departmental Committee upon the Prices of Building Materials as to why the price of blue Bangor slates in London has risen from £9 15s. per 1,200 in April, 1914, to £26 5s. in November, 1927; and why Welsh slates have risen in Birmingham from £8 per 1,200 in 1914 to £24 10s. in 1927?