[The editors arc not responsible for statements made in the correspondence column. AnonY1ous C01nmunications cannot be considered, but the namcs 0/ correspondents will be withheld when so desired.] Audibility of the Aurora To the Editor of the Scientific American: If your paper is interested in the above question, you can easily set Prof. Tromhiolt right by sending one of your staf to St. John, N. B., or Halifax, N. S., during the fall months, or better in the early winter, and he will then hear the sounds from the aurora, and perhaps it is possible to phonograph th'em. I have heard those sounds thousands of times, particularly on very cold and clear nights, while living in St. John thirty to forty years ago. They sound like the swishing of switches through the air, and at times like the detonations of small fre crackers; at other times they sound like distant musKetry, as if fring away from the heaven. The sounds, as r remember them, do not appear unless the aurora is moving, which happens often enough for observation. New York city. R. Flaherty. A Plan to Protect the Poor Inventor 10 the Editor of th( Scientific American: As I believe that a meeting of the International Congress of the Union for the Protection of Industrial Property is soon to take place, I take the liberty to submit some suggestions that I trust will be useful and worthy of consideration. It is a wpll-lmown opinion among a majority of manufacturers and inventors of limited or liberal means, that the term of a patent is at present too short. It is also well known that the protection as to right of priority of invpntion is not as perfect as it should be. The manufacturer, wben he fles an application for a patent, has the capital necessary to put the article on the market and to fght through the courts not only' the infringfrs but such patents as are in the way, even though th!y do not fully infringe. The inventor of limited means, at such times, lacks perhaps the experienced experts of the manufacturers that are ever ready to give any testimony in litigation to prove priority of invention or other facts; and at the best all that said inventor can secure, with his more honest but poorly defended evidence, is of very little importance and hardly satisfactory. To remedy the above two conditions I suggest: 1. That the term of a patent be extended to twenty years. 2. That the frst and fnal patent fees be $20 each. 3. That each patent thus issued shall be renewable for ttm more years upon the payment of a tax of $200. 4. That a second renewal be allowed to each patent upon the payment of a tax of $300. 5” That each inventor, to prove his priority of invention, be allowed to prepare his own rough sketches in secret, as the development of thp invention progresses, said secret sketches to be presented for sealing to a judge or other high official in the district in which the inwntor is located at the time. 6 . That the sealing before the judge or ofcial be made under oath after the payment of a tax of $1, the sealing being of such a prescribed character that it will not disclose the nature of the invention at the time, and will prevent interference with the contents of the package after sealing, and that will also indicate the date of sealing, the district where the sealing took place, and the name and position of the ofcial sealing said secret sketches, which may be identifed heroafter by the term “Priority Proofs." 7. That the inventor be allowed the option of holding said priority proofs or of fling them in a special department in the Patent Ofce. 8. That said priority proofs shall not be examinable, when fled, until the time of the fling of the formal patent application, and then only after a request to that efect by the applicant. 9. That an inventor be allowed to secure as many such priority proofs as he may deem advisable. 10. That the presentation of the earliest or of all of said priority proofs, secured for one invention, under the proper seals, shall be considered as prima facie evidence in any dispute of priority or technicality arising during the examination or litigation of any patent case. It can be seen from the above that if A has an invention fairly well defned in its form, but still subject to a series of developments, he can under oath secure, without disclosing his invention, a priority proof under (, be seal, date and signature of a judge 01 other high official, and thereafter follow the development of his invention for a period of time until it is ready for the formal fling at the Patent Ofce, the inventor feeling all this time his work is under protection of priority. This will also help many inventors that cannot aford at the time the expenses of a 'patent application, giving them the opportunity to save or raise such moneys after they have sealed their priority proofs and assured their inventive rights. The priority proofs are not examinable, and, except for the fling, they will cause no extra work to the Patent Ofce, until requested by an applicant fling a formal patent application. The priority proofs will tend to eliminate the abuses of expert testimony, at present experienced in certain patent litigations. Another point 1 wish to call to your attention is the lack of patent protection accorded Americans in foreign countries under their present laws. While we issue a patent for seventeen years without yearly taxes except the initial fees of $35, most of the foreign countries issue patents for ffteen years for an initial fee like our own, but subject to a yearly tax on each patent as well as working clause. Both of the above features are objectionable to the interests of the American inventor and manufacturer, and there is no reason why we should allow the privileges under our laws to the foreign patentees whose countries refuse to allow similar privileges to our inventors. The loss to our inge1uities and industries is pronouncer. An inventor llaving a valuable invention, patents the same abroad. In trying to sell it, when he cannot manufacture it himself, he experiences much delay at the hands of certain manufacturers, with the result that thE working time limit comes right upon him. After such time, his patent being belittled in value, can be and is fought, and declared null and void, and thereafter every manufacturer abroad reaps a harvest upon the hard labors of American ingenuity. In consequence, the American fnds it difcult to control many an article in the foreign markets, and very often hard to compete with similar productions of such market. Even manufacturers that, for certain reasons, have found it impossible to manufacture their patented articles abroad, have had their patents abrogated and lost considerably thereby. At the same time, a foreign manufacturer can secure a patent in this country under the liberal system, manufacture the article in his own country, at low cost of labor, and importing it here and selling it at a lower cost and better proft than in his own country. This also explains, in part, why' a number of the foreign countries are not so often subject to the periodical industrial retardations that are so current in this country. The inventor with limited means possibly fnds himself, after delayed negotiations or litigations with foreign manufacturers, unable to pay the taxes, and the loss of the patent is the result. It would be a very patriotic and conservative policy on your part to urge legislation to the efect: 1. That the citizens of a foreign country, not residing in the United States, and whose country issues patents to American citizens under the time limit clause and yearly tax clause, shall be able to receive and hold their patent rights in this country only upon working their invention in this country within three years from the time of the issue of the patent and upon the payment of a yearly tax of $20, beginning from the second year. 2. That upon the failure of the patentee to work his invention within the prescribed limit of time, iis patent shall be open to contestation and annulment. 3. That upon the non-payment of the yearly tax, said patent shall be declared null and void. 4. That the citizens of such foreign countries as accord to the American inventor the same privileges that are accorded by the United States laws to its own citizens, shall be exempt from the working clause and the yearly taxation. These points when brought to the attention of the foreign delegates at the coming convention may prompt them to suggest or formulate modifcations as well to their respective laws as to the Union of Industrial Property clauses that would be more favorable to the American inventor and manufacturer. The foreign countries can easily suspend the working clauses and yearly taxes, and if they need the money from such taxes they can make it up by increasing the initial fling fees. They can easily realize that by removing the above objectionable clauses from their laws they will encourage invention to such an extent that the initial fees of the increased number of patent applications will more than compensate for the change. A great majority of the American inventors WOUld, under the new conditions, fle foreign applications, while at present they do not care to do 10 because of the existing uncertainties. r trust that these suggestions will receive the approval of a great many inventors, and therefore will attempt to give the American inventive public an opportunity to take up .the subject and debate upon the merits and demerits of said suggestions. It is the cause of the inventor with limited means that must be progressed, for they are the pioneers in all great things, as is evidenced by the manufacturers looking to them for meritorious inventions more than to their own experimental stafs. The time is now ripe for such a move on your part, and I therefore urge you to give due attention to the matter, presented, as it is, as a conclusion of views given by inventors, manufacturers, and attorneys. New York city. 1 B. T. Electric Fans for the Sick To the Editor of the Scmntific American: A subscriber to your paper has written us, calling our attention to a short article in your issue of July 22nd entitled “Electric Fans for the Sick,” the same referring to the practice of The Electric Supply Company at DeKalb, Ills. This gentleman, it seems, had heard of the order issued to all of the electric properties under the control and management of H. M. Byllesby&Co. early in July, directing that electric fan service be furnished free to all invalids who were unable to pay for the service, upon presentation of the proper certificate from attending physician. This order meant that in 106 cities and towns in the West, Middle West and South, any indigent sick person might obtain fan service during the hot months absolutely free, the local company not only providing the fan, but extending the service lines and temllorary interior wiring where neeessary, and furnishing current. This action has resulted in a great deal of favorable comment both by press and public, and II nearlY every city from six to eight fans were immediately placed in commission under the terms mentioned. The idea so far as we can learn originated with the electric light and power company at Rochester, New York. As soon as Mr. Arthur S. Huey, vice-president of H. M. Byllesby&Co., heard of it he immediately issued the order described above, which directly reaches invalids in a total population of nearly one million people. H. M. BylleRby&Co. By W. H. Hodge, Publicity Manager. The Postal Aeroplane REPOR'DS come from .ngland and France that the ofcial postal aeroplane for the rapid transport of mail matter is soon to become an actual reality. On August 13th Pierre Vedrines, the veteran aviator, winner of the prize for his recent notable aerial trip from Paris, France, to Madrid, Spain, made one of ten fights to demonstrate the possibility of an aero mail sefvice. This fight was most successful. He left Issy-les-Moulineaux near Paris with mail aboard at 5: 07 P. M. and reached Deauville, near Trouville, 112 miles from Issy, at 6: 50 P. M., or one hour and forty-three minutes, or at the rate of a trife over sixty-five miles an hour. The time of the fast express train going the same distance is 3 hours and 12 minutes, or 1 hour and 19 minutes longer. On the way Vedrines dropped letter packages at Mantes-sur-Seine, Evreux and Lisieux. It is said he was paid fve hundred dollars for the fight, which would average a trifle less than $5 per mile. In London the Post Ofce Department is making preparations for the early inauguration of a special aerial postal service to be carried on between London and Windsor a distance of twenty-one mHes. Special aerial post boxes are to be placed in public places, in which letters for this service must be deposited the same as in ordinary boxes. Collections by carriers will be made in the usual way and deposited in a central location, from which the aeroplane will depart. There the mail will be placed in sealed letter bags and the latter strapped on to the aeroplane. The fight to Windsor will occupy about half an hour. From Windsor the mail will be forwarded by train to its intended destination. King George has given permission for space in Windsor Park to try out this experiment, which is to last a week and perhaps longer. The time is now at hand when it would be in the line of progress for congress to make appropriations for an experimental aerial postal service between two cities, as for example between New York city and :hiladelphia, providing fOl hourly fights each way. Operating at a speed maintained by Vedrines in the Paris experiment, a letter could be sent from New York in the morning to Philadelphia and the sender receive an answer in the afternoon.