Owing to the nature of a number of communications recently received, and for which answers are requested through the correspondence department of the magazine, it is desirable to explain the purposes for which this department is conducted. The amateur worker frequently meets with problems the solution of which cannot be conveniently secured, owing generally to the lack of acquaintance with some one skilled in the particular matters at issue. As this magazine has a large number of contributors who are workers in many different lines, it is a simple matter for us to refer an inquiry to the one most acquainted with the subject, and an answer easily obtained. This service we are pleased to render when the subject matter would be of interest to anyone other than the person making the inquiry, as much interesting information is thus made available for all our readers.
When, however, an inquiry involves considerable mathematical work which would be of value only to one person, such as working out the wind-ing specifications of a dynamo of unusual or discarded type, we shall hereafter be obliged to receive such inquiries subject to the convenience of those to whom they may be referred for answer, and no one should be disappointed if no answer is returned, although in such a case, if stamp is enclosed, the writer will be informed why no answer can be sent.
As we desire to make the magazine of the greatest usefulness, and as many readers are likely to have problems of a technical and personal character for which they desire solutions, we have decided to receive such inquiries subject to a fee, the amount of same to be as small as can consistently be made, and which will be communicated to the writer before referring the inquiry for answer. In this way we shall be able to give our readers skilled technical service at the lowest possible cost, and avoid the feeling of reluctance held by some, who wish information but have refrained from writing for it because of the amount of work required to properly prepare an answer.
Owing to the large number of replies received in the suggestion offer mentioned in the editorial column of the June number, the announcement of the awards has been postponed to next month. Our sincere thanks are given to those who have so kindly aided us with so many valuable suggestions, which will be acted upon as soon as possible.
A jet of burning oxygen from a blowpipe is now successfully employed to cut sheet iron, iron tubes aud small bars. The cut made is almost as sharp and thin as that made by a saw. In the earlier experiments difficulty was encountered in clearing the cut of liquid metal, and in preventing the spread of the melting effect beyond the borders of the cut. In the process as now practised, two blowpipes are employed. The first has an ordinary oxyhydrogen flame, which heats the iron to redness at the place where the cut is to be made. This is to be followed immediately by the second jet, composed of pure oxygen, which instantly burns the metal without melting. The liquidized iron is blown swiftly from the fissure, so that there is no serious spreading of the heal to the surrounding parts.