An international trial of reaping machines, under the auspices of the Royal Hungarian Board of Agriculture and Trade, is projected by the Agricultural Society of the County of Wieselburg at Ungarisch-Altenburg, from the 5th to the 10th of July, 1869. The following rules have been adopted: I. No other machines but reapers are admitted for trial and competition. II. Reapers generally require a greater draft than that of two Hungarian horses, and for this very reason these machines have not, up to the present time, been in such general use as could have been wished ; therefore, such competing machines will be preferred which do not require a greater draft than that of two middle-sized horses, their effect being of course in proportion, III. The utmost simplicity consistent with durability in the construction of the machine is one of the first conditions for an award of a premium. IV. Apart from all other qualities* a machine with self-delivery will be preferred, or a combined one to be also used for mowing grass. Thi said qualification is not * however, absolutely necessary in machines requiring but light draft. V. All other qualifications being equal, preference will be given to those machines which will cut tangled of lodged grain, require least manual labor, scatter least corn, waste least straw, are the easiest to move, are lowest in price, and which deliver the straw in the most regular manner to admit of the sheaves being bound in the readiest way. VI. Experience has proved that the Hungarian oxen, from endurance, strength* and swiftness, are well adapted for working reapers, the Agricultural Society therefore think it desirable that the speed of the knives of Such machines which require more than 250 German pounds, should be modified to suit the pace of the native horses and oxen. The poles must also be arranged for oxen. VIII. Premiums will be offered as follows : First, for reapers constructed with self-delivery : 1st prize, 60 ducats and a gold medal. 2d prize, 40 ducats and a gold medal. 3d prize, a large silver medal. Second, for reapers not constructed with self-delivery : 1st prize, 50 ducats and a gold medal. 2d prize, 30 ducats and a gold medal. 3d prize, a large silver medal. VIII. The jury, which, consists of Professors of the Royal Agricultural Academy, of Ungarisch-Altenburg, by approved deputies of the agricultural societies of Pest and Vienna, and representatives of agricultural societies of various countries, will pronounce its j udgment on the reapers in a competent and strictly impartial manner. IX. All other points not specially mentioned here, with regard to awarding the prizes, and the system of proceeding to be observed, will be arranged by the above j ury. X. Every competing reaper must cut no less than one Austrian acre (equal to about 7,000 square yards). Each competitor will have a suitable space allotted to him to experiment on previous to the trial. Horses or oxen for all trials are furnished by the Committee. XI. No competing machine is allowed to withdraw before finishing the trial without the consent of the jury. XII. The Agricultural Society, in inviting all native and foreign manufacturers of agricultural implements to send reapers, announce that the proper authorities will be requested to grant a reduction of freight and toll duties, the result of which request will be published as soon a possible. The competing reapers are to be sent "Zur Ernte-maschinen-Concurrenz, in Ungarisch-Altenburg, letzte Eisenbahnstation Wieselburg, an der Wien-Neuszonyer Linie, Ungarn." XIII. Manufacturers wishing to send reapers for this exhibition are requested to give notice before the 30th of June, to " Herrn R. Rath Paul Major, Vice-Pr sident des landwirth-schaftlichen Vereins Ungarisch-Altenburg," giving the number of reapers to be sent, stating whether self or hand delivery, the prices at factory, and it possible, the prices delivered both at Vienna and Pest, and further, whether a man will be sent to work the reapers or whether the society are to provide One. The 30th of June is the latest day for the arrival of reapers at Ungarisch-Altenburg. N. B. The Committee will see that all due care is taken of the machines on arrival. XIV. The Agricultural Society will also publish a precise report of the trial of the reapers, so that the result may be known both in Hungary and in foreign countries. The Secretary of the above society is Charles Kopfmann, who may, we presume, be addressed by parties interested. u a Smoky Chimneys. The Architect, a London weekly, gives the following summary of the causes of smoky chimneys, condensed from a new work on the subject, published by Longmans, which seems certainly very comprehensive as well as concise. " Want of sufficient hight in the flue. The outlet of the chimney being placed in an exposed and cold situation, while the air with which the fire is supplied is drawn from a warmer and more sheltered region. Excessive width in the flue, by which a large volume of cold air is drawn in and allowed to lower the temperature of the ascending column. Low temperature of the interior of the flue in comparison with that of of the external air. Humidity of the air. Too accurate fitting of the windows and doors, and joints of the flooring. The draft of one fire injuring that of others in the same house. A current caused by the heat of the fire circulating in the room. A flue of insufficient size. A foul flue. Displacement of masonry, or accumulation of mortar within the flue. The sudden obstruction of the draft by gusts of wind entering the chimney top. Increase of density of the air at the chimney top, due to the effect of wind in chimneys rising from the eaves of roofs. Drafts within the room which throw the smoke out of the influence of the ascending chimney current. " Of course the remedies consist in the removal of these causes, but the suggestion given that the kitchen flue should be at the north or east end of a stack is sagacious; also, the recommendation to supply fire with air for its own consumption, drawn from the coldest side of the house. The arrangement proposed with this aim is ingenious, and no doubt capable of easy and effective application in a large proportion of cases ; but the question of the exact position, size, and adjustment of the air inlet near the hearth appears to us yet open to further investigation ;.and it must not be forgotten that any such arrangement dimishes the efficiency of the open fire as a ventilator of the room.”