it would be far better for all concerned, especially for the users of patented devices, for they would then avoid vexatious delays or expensive law suits. My purpose in referring to various patents in the begining of this paper was to bring out the fact that many patents involving the use of alkaline cyanides for the solution of the precious metals have been issued. The question of the filter press bids fair to be a quiet one, the solution apparently being largely in the age of this device, and in the fact that patentees have been limiting their claims to details of construction instead of attempting to cover broad fields. At the present time the treatment of telluride ores seems to have found successful solution in the roasting-cyanidation method, and shortly before the fire which destroyed the Dorcas mill, results were being obtained that left little to be desired. The use of the electric current as an aid to solution of gold and silver has not yet met with marked success in ore treatment, but there are good reasons for believing that with many ores greatly improved extraction could be obtained. In like manner the many suggested oxidizing agents have never been extensively adopted, and when oxygen is needed as an aid to extraction it is usually added by some method of aëration. Preciptation of values simultaneously with extraction and in the same vessel has also failed of general adoption, mainly because of mechanical difficulties. The most important problem before the metallurgist for solution is that involved in the treatment of silver ores, for while high percentages of gold may be extracted with little difficulty, silver on the other hand, with few exceptions, yields very imperfectly to cyanide treatment, an average extraction being somewhere about fifty per cent. There is much room for discussion of the relative merits of the various methods of charging and discharging vats, of slime handling, of precipitation of values from pregnant solutions, and finally of reduction of these values to commercial form, and it is greatly to be hoped that this general paper will be followed by others in which details of treatment are exhaustively considered. "Helion" Filament. The latest advance is a filament devised by Professor Parker of Columbia University, to which the name "helion" has been applied, on account of its sunlike light. It is reported to be a carbon filament impregnated or covered with silicon, of great resistance and durability and capable of soldering its parts together at a break. Selective radiation is claimed for it. It is said that it emits a white light at a temperature at which carbon is only red hot. EXPERIMENTS WITH ELECTRICAL TREATMENT OF BOILER WATER ON THE EL PASO & SOUTH= WESTERN RAILWAY SYSTEM.' By J. L. CAMPBELL. Engineer of Maintenance of Way, El Paso & Southern Ry., El Paso, Tex. The worst wells on our road are east of El Paso. After we have treated these exceptionally bad waters, which cover a distance of 128 miles on the Eastern Division, they are still of bad quality, and as a result our engine tonnage is reduced 25 per cent and the excess annual maintenance on locomotives is approximately $1,000 per year per engine. Generally we cannot reduce the incrusting solids in these bad waters below 20 grains per gallon without producing an inadmissible amount of foaming; consequently, we have exhausted the practicability of the lime and soda ash treatment. During the past year we have been experimenting with the electrical treatment of some of these waters. At Alamogordo we reduced the incrusting solids from 40 grains to an average of 6 grains per gallon, and at Pastura from 140 to 30 grains. It was possible to still further reduce the Pastura water by increasing the intensity of the electric current and the time of treatment, but we have ascertained that the electrical treatment is impracticable on account of the excessive cost, which has run as high as $1 per 1,000 gallons for the worst waters if treated down to 10 grains and less per gallon. The method of treatment consisted in submerging aluminum of iron plates in the water to be treated and passing an electric current through the plates, which were suitably connected up in series. The experimental treating plants consist of a series of wooden vats, each of which is divided into a number of compartments, each compartment containing a large number of aluminum or iron plates set on edge in grooves and spaced from 1⁄2 inch to I inch apart. In one of the plants the water flowed continuously by gravity through the vats. In the other the vats were filled and the water remained stationary until treated, when it was emptied and the vat refilled. For a number of reasons the intermittent treatment would probably be the more practicable in continued use. The aluminum plates experimented with were about 12 inches wide and 3 feet long; the iron plates are about 3 feet square. Both kinds of plates are dissolved in proportion to the amount of water treated, and we find the expense of the renewal of plates is a very large 'Abstract of a paper in Bulletin No. 91 of the American Railway Engineering and Maintenance of Way Association. item in the cost of treatment. As a result of the experiments, our conclusions are that the electrical treatment is not practicable on account of the cost and the large amount of work involved in the daily operation, cleaning and maintenance of the experimental plant. On the division of the road above specified, where the waters are so bad for a distance of 128 miles, we have adopted a very radical remedy, which consists of bringing water by gravity from the White Mountains to and along our railway for a distance of 130 miles by means of a combined gravity pipe line and two pumping plants to lift the water over a divide. between the Rio Grande and the Rio Pecos drainage areas. The water from the White Mountains is of a very superior quality, averaging about 5 grains incrusting solids per gallon. This pipe line will eliminate all of the present water supply, which cannot be successfully treated with lime and soda ash; in fact, it will eliminate all of the treating plants we now have, with one exception. The estimated cost of this supply of pure mountain water is $1,300,000, but we find that its capitalized value will be several times that amount, from which the seriousness of the water condition in the past can be judged. Our present water supply in question has an annual charge against it of 98 cents per 1,000 gallons, which includes charges for reduced train tonnage, the excess annual repairs to locomotives and incidental impairment to the efficiency of the service generally. We estimate that the pipe line supply of water will carry an annual charge of 16 cents per 1,000 gallons. High Temperatures. The fact that high temperatures are now daily obtained by means of the electric furnace, the oxy-acetylene blowpipe and other artificial means causes an interest to be manifested in the actual temperature that is reached in melting refractory materials in the sun, whose temperature is the highest known. Experiments with the optical pyrometer recently made are of interest as indicating the temperatures that are reached in certain operations and in the sun. These results are as follows: The results are of interest as they indicate the temperatures of familiar things. Curate with, nor want me. Mary instruments that are satisfactory in every wher regard fail in this requirement, either necessitating constant re-stan-iatószalon or øke dowly burning out with long exposure to a high tem In addition, dhe pj rometer should be simple and easy to use, so divat ut is ta eavily injured or put out of adjustment. It should be capable of waking a confirnom record, for in many cases the chief use of pytrabattic determinations is the securing of uniformity and constancy of Passing over the liquid and gas thermometers, which in their pres- ent state are adapted to measure fairly high temperatures, but which are not generally fitted for industrial conditions, and are not capable of making a continuous record, we come to the pyrometers that make use of the differential expansion of an iron-carbon rod under heating. These were used to some extent a few years ago, but they are no longer regarded with favor. They possess all the disadvantages of the mercury thermometer, except liability to breakage. With continued use the iron rod becomes permanently expanded, and the scale no longer reads correctly. An early type is illustrated by the Seger cones. These are slender cones of refractory materials, china, clay, quartz, etc., the composition of the mixture being so adjusted that it fuses at a given point. By using a series of cones of graded composition, a scale of temperature is obtained. A cone is considered to be fused when its top bends so as to point directly downward. Like the pneumatic rock-drill, Seger cones are theoretically unsatisfactory, but in practice they are better suited for use in their own particular field than any substitute. They measure a rising temperature only; the fusing point is affected by the rate at which the temperature rises and by dust and the gases of combustion. Nor is it possible to obtain a continuous record, but because they are of similar composition to the material being heated in the manufacture of clay products, and consequently both are similarly affected, they are satisfactory in spite of their inaccuracies, and therefore this type of pyrometer remains in common use in the manufacture of porcelain, china, earthenware, and brick. Recently more accurate methods have been introduced. 330 to 1650 mm Boxwood Porcelain 4 Platinum Leads Mica Discs Platinum Coil Several types of pyrometer depend in their action upon specific heat. The Siemens pyrometer was practically a calorimeter. A ball of the proper size was placed in the furnace and allowed to come to the same temperature. It was then removed and placed in a known quantity of water, and from the rise in temperature of the water the temperature could be computed. The objections to this are obvious. Another method is Fig. 2, to lead water with a constant rate of flow through the furnace in an iron tube. By measuring the temperature of the influx and the outflow, the temperature of the furnace is easily computed. In the ordinary application of this method the computation is done mechanically. The inconvenience attending the use of this apparatus is also apparent. A method which has found some application to the measuring of the temperatures of hot blasts is to divert a small portion of the blast through an apparatus somewhat like an injector, so proportioned, usually, as to take in |