The Secretary read the following report, made by Mr. Boexsww on the 18th instant: The select committee on ventilation report: That ejeint selecton itteeof the two Houses of Congress was appoints under a Jtresolution, paroledat the 1st semion of the 38th Concm. to examine into the condition of the Senate hamber and hall of the HoRep regardstheir lighting. heating, 1:iid ventilation, and their acoustic properties. an the defectsand disad wnntagesexisting in the same. The committee consaiust the doroitfythr eemembers from each House, and under 0! the resolution of appointment made an elaborate written report to their reepFectiveHouses upon the subjectsre erredto themin ebfllafff1866, Exec Senate committeere iort No. 128, 38th congress. 2nd session. The report was accompanied by sundry documentsand the evideno' 0 taken before the committee. This committee concurring in the main in thorca soning and conclusions of that report and having reinvestigzited the subjects covered y it. havenowto recommend the carryiu into effectof the plan of imirovcments containc in said report. n making further observations upon the plan of improrgment. The committee will confine themselves to tiicpenpte wing of the Capitol, with the condition of which. in regard to its ventilation and sanitary condition, they are particularly concerned. The committee are impressed with the conviction that perfect or satisfactory ventilation of the Senate timber ognnot be secured so long as the present roof is retained. The area of glass surface or the admission of light in the Senate roof exceeds 3,400 squarefeet. The remainder of theroof is much moreextensive, and is composed of coplper of a H is thickness. Below this metal and 3 ans roof an separated from it by th e air lpnos used for illhl IDI 0 Chamber, is the ceiling, l extendingover the ivholq Chnmber and composed of glass and iron. The ine ritable result of these nrrnntle rnents is. that the Hall becomes ine rdinately heatedin summer by the direct ndllllclrllilflof solar rays and by the radiation of heat from the glues and metal, of which the roof and ceiling are composed. The temperature of the Hall is therefore often elevated to about 90 Fahrenlicit during the sessionsof the Senate: besides. at ight SO $lO'lS, the temperature on the floor of the number is ele vated as mu c has llve or 6 degreesby the liirhts gibinjethe eeilinz. This is the easein summer: but in meter. on the contriiry.the roof goneriitescold in enormous quantity, producing irregularity and disturbance, aswell as expense.in the ventilation of the Chamber. In short. t a committee believe that the roof must be removed or changed in order to any satisfactoryventilation of the hall. And that a change should also be madein the manner of lighting the Hall from that now established. The present roof wasnot a by featureat the original plan of the architect deswi hnoomd. tBhye twhaintgpslaonf litghhetewaapsitol extension were to he admittedinto ttihoen, wluhllicbh ywsoidueldwginiVdcofwresepinlagcreed ssin.whitesnuepvpoerdrcesleirvcad to the external atmosphere and would have avoided all thoob;cctionswbich exist to the presentroof. lly slacing side Windows around the llall, making them cubic, pnd, when necessary, shading the spexposed to the direct rays of the sun, perfect illumination of the Hall lllCitldlllR the fioor andgallerics, wouldhave been scoured and all imurions influenceof external heator cold excluded; and, besides, the pure exter nal air conld whenever desirable have been admitted. By simply opening the windows: and then, by haying a closed roof, madedoubleor counter ceded.all noise of stornis would have been excluded and most of the existing diflleulties in ventilation avoided. 2 remedieshave been proposedfor the defects arisiu from the existing arrangements: the ono, to nbolis the presentroof, substituting one of different construction and to place side Windowsin the upper part of thelliill, asoriginally intended; the other.to removp the hal to the side of the Capitol ivinir. The obicctions to the latter plnn are very strong, and maybe regarded as decisive. The cost would hevery grott. many inconveniences would be encountered in t a general arrangement of the Wings, and the resuits would not beentirely satisfactory as to the hall iatdsemlfi.t sSoimdee wipdows near the level of tbo floor would noise: the light from themwould bedirect and offensive in certain situations' they would, when open, reduce currents of air directly upon members, an would produce irregularities of tom peretura in the Hall. Besides. t adoptin: e difficulties of a plan of regular and effective ventilation would recur upon us in adopting this arrangement. But recurrin to the other plan'of Windows in the upper part of the Hall. in connectionwith the other e nnges proposed by the architect, and recommended in the former report of the JtComof the 2 Houses, we 0 tom.asthe committee think. complete and satisfactory results, By abolishingtherp of wesecurethe Hall from its direct and enormous influenceupon temperature, avoid the noiseat storms, and are enabledto obta n complete and regular control of theyentilation oi the Hall. And by substitut ng a fewlights With reflectors and vontilathig chim ncys for the present gas Jets, we avoid the undue production 0 heat at night sessions. The plan also enablesugto obtain pure pir at all tiii ies with perfect faeili y, to hydrate it in Winterin its passage to the Hall and to cool it in summer, and to removeit with certainty and regularity git all times ironrthe Hall before it becomes contammstedby respiration. The committeeWlli not repeat the explanations and reasonings of the fofmer report, although they are necessary to the nu comprehension of t ie subject. They will coptentthemselvosWithreferringto abut report as satisfactoryupon all the points rind etails of the plan nowlet!unnoticed. But twopoints mentionedinfhe former report may deserve some further attention. The 1st is the exterior or upward elevation of the wing: and the 2nd, the proposed downwardmovementpf the air throughthe Hall in the processof ventilation. The slight elevation of theoentrol part of the wing, asproposed, will break the horizontal sky line of the building, and will conformto the order of architect luinreesupoof n which the capitol wasdesigned. Theouter elevation will e behind the Lprotectionsof the porticos, colonnades, and mpstof o alustrading new placed upon the exterior walls. Elli! committee he love the clfeetwill be pleasing t the‘eye, while the work will becon Formedto the principles of art. The attic ilcsizped will not be necessaryto the practical results desired in the ventilation of the Senatewing, but may be yiindicatedasan architectural addition. It neednot.however.beimmediately erected. The downward movement of air, in ventilating public buildings, discussedin the forme rreport, is Britaln and France. eannddetdobysroemceen expence oin in Grtchaist country. It has been completel successfulas applied to the Commonsilouse of arliauient. nd to other public structuresin Ensland, and it is the au cepte systemin France. Thereceut able and ox haustiveworks of Geperal Morin upon the ventilation of the public buildingsof Ppris has been, at the instance of the committee.examinedby a gentleman of high scientific character and the result is a complete indorsement o the viewsof the architect who planned our Capitn extension, and who pew propose: to apply his annual principles in its improve men. The committee recommendthpt the plan of improvement be carriedinto executiondunn the coming year, under the managementof Char soP. A person as architect and superintendent: the details and pl unitof the work to be examined and approved throughout by Dr. ThomasAntisell.md all contracts to he made under the authority of the ComrPubBldg. The work can be fully completed during the coming year and all preliminary arrangements can be made plans perfected, nndma terials and Workeontractedfor before or during the next short session of Congress.