Tho conunittuc oí' tlio city governmcnt have prepared a bilí to govorn tho future oonstrucüon of bxuldings in Boston, which waa Bubmitted totho Legislativo Comniitlee on Building ia session on Monday. It provides fur an iacreaso in rhu tliiekn(.ps of wfllla of all clubes ol' Buildings. Tho ininiinani thiokness of extreme walla of all buildings other thau dwelling houst'S, more thau thirty fcet high, shall be sixteen inches, and party walls shall be twenty inches ujtj the second floor abovo tho streot, tuteen inches from the socond floor to tho roof, and twlve inohos through tbu roof; external walls of buildings not more than thirty ffict high und forty foot in length and width must not bfi luss thau twolvo indios tluck. In all buildings of two stories or more that exceod twenty-iivc feot in width, and that are not supported hy party walls or girders, the extornal walls niut bo increased au additional four inches in thickness for every twentyfive feet in width. All brick party wiiils shiill be. carriod up to the hight of (wo and a half fcet above the roof covering, aufl if the roof is a Mansard they sliall be carried two nd a halt' fout ,ilovo the upper fAope and eightoen isohea through tho lower slope, ho aa to alïbrd complete protectiou against fira extonding from building to building. AU puty walls must be oorbeled out so that tho corniceH umi gatten shall bo complotely separatcd nnd uil timbera entering into party walls must be separatcd by íour inch'ja of maaonry between thei.' :;.ls. The construction of any party or partition walls npon "woodon supports, and the uso of timber in walls whcTO brick or stnne aro comiitouly usod aro prohibited. íío person hall build the raar or party waUaofa building one at a time, but shall oarry j theru up together, tying theni firmly. All wulls mwt b . tied together as a building goea lip, and all thu Üoor beams and timbera used must bo ironed together. Tho building of Mansard roofs of more than ono story in height is prohibited onleas constructed of fire-proof material thionghout. AU parta of all buildings which are moru thiin forly-livc feet above tho lovcl of thu siucwiilk danst be niade of or eovored wit.h non-combnstible material, and the roofs of all buildings which axoeed fifty-five iVut above the levul of tho side welk muat be oonatruoted of iron ór non-conbu.-stiblu material. It also provides thiit boilor nnd enginoroonis üliail be eonstructed ftre-proof throughout; tho stores and store-l ehall have fire-yroof doors and shutters. I ín buildings where operativos are employed fibovo thu sccoiul story gome humus of escape on un occasion of liro must be provided ; muí jn tonemcbt houses, whtré Ihe lowet Btory :s occupioil ns store, the lover hall portition must be Imilt of briok, so that Lo oase of n fire in the store, meann ot'cxitfor thoso living abovo may nut bo cut ofF.