In another experiment undertaken with a view to "cracking," &c., treating and redistilling with soda, the products were as follows, stated in percentages of the whole quantity operated on, the several steps being as before.

Naphtha,* sp. gr. about 760 at 60° F.,

Oil,t

66

11.33

The illuminating oil from both these experiments, after treatment with sulphuric acid and soda in the usual manner, acquired an agreeable odor, a light straw-yellow color, and burned as well in a lamp as good commercial oil.

With a view to test the effect of heat aided by pressure in breaking up the heavy hydrocarbons-a method of treating heavy hydrocarbon oils patented in 1866 by Mr. James Young of Glasgow-a portion of the first distillate from the crude oil was subjected during distillation to a pressure of ten to fifteen pounds to the square inch, in an apparatus adapted to the purpose, the distillate thus obtained being about the same density as in the first named experiment, 890 at 60° F.

From this distillate were obtained, after the ordinary treatment with sulphuric acid and soda, the following products:

The illuminating oil from the last experiment flashed at 80° F. and lighted on the surface at 85° F., showing the presence of naphtha or some very light body, the quantity of which cannot be very considerable. The light oil could with care be taken off in practice without materially diminishing the yield of illuminating oil. It would be rash to conclude that there may not be an important economical advantage in employing in the large way Mr. Young's method of treatment under pressure, over that of "cracking" by a regulated heat alone. It is highly probable that there would be found an important saving of time, as under a regulated pressure and a corresponding increase of temperature, the transformation of the heavy oils into a mixture of those of less density, will occur more speedily. The experiments herein mentioned gave nearly the same result whether

This naphtha caught fire from a match at an atmospheric temperature of 56° F. + This oil flashed at 113° F. and ignited at 124° F.

pressure was used or not; a certain loss, all falling upon the lighter portions, was found to result from leakage of the apparatus under pressure, which in the larger way of operating commercially could be avoided.

No paraffine could be detected by refrigerating the heavy oils obtained in these distillations in a mixture of salt and ice. It is no doubt the absence of this body from the series of products obtained from the California oils generally, that accounts for the illuminating oil burning well at a density considerably below the commercial standard for oil obtained from Pennsylvania petroleum-a difference enhanced also by the absence of any considerable quantity of light naphtha. The lubricating oils of this series, likewise free from paraffine, retain on this account their fluidity at low temperatures.

The light oils obtained in this series of experiments correspond respectively to 12.96, 14:56 and 18.96 per centum of the crude oil. The total commercial products are about 60 per cent of the crude body, which likewise yields sufficient coke to supply the fuel required in the distillations.

In the large way, by returning the lightest oils to the heav ier portions in the successive distillations and employing Mr. Young's method by pressure, it is probable the product of light or illuminating oils may be raised in these very heavy natural products to 30 per cent.

It is evident from these experiments that heavy hydrocarbon oils containing no naphtha are convertible into oils of the naphtha series under the action of heat by molecular transformations, the excess of carbon being left behind as coke; each successive distillation eliminating a new but always a diminished portion of carbon.

I am indebted to Mr. A. J. Corning, formerly assistant to Mr. Warren, for conducting this research under my direction; and to Messrs. Downer and Merrill, of the kerosene works in South Boston, I am under many obligations for the permission to employ their operative laboratory in conducting this research. As before stated, the research had chiefly a technical object, the points of scientific interest being subordinate in a great degree. For the crude material operated on I am indebted to the Califor nia Petroleum Company, from whose estate it was derived.

Note. In the number of this Journal for May, 1865, I published the analyses of a sample of crude petroleum, believed by me to be from a well-known spring, called the "Pico Spring," in Santa Barbara county, California. This sample, as well as a subsequent one in larger quantity, came to me under seal from responsible parties and no question of its authenticity, until a very recent period, ever reached me. It is now confidently asserted,

AM. JOUR. SCI.-SECOND SERIES, VOL. XLIII, No. 128.—March, 1867.

by certain parties, that the samples in question were sophisticated by the addition of refined commercial petroleum. An inquiry instituted privately by me has elicited from the parties immediately concerned in its transmission only an emphatic denial of the charge of falsification, and if any such fraud has been perpetrated I am well persuaded that the responsibility falls elsewhere. My investigations in this direction are unrelaxed, and the truth cannot remain long concealed.

New Haven, January 14th, 1867.

SCIENTIFIC INTELLIGENCE.

1. CHEMISTRY AND PHYSICS.

1. On the influence of the absorption of heat upon the formation of dew. The long pending controversy between Magnus and Tyndall in relation to the absorptive power of aqueous vapor, appears to have been brought to a conclusion by an experiment of Magnus based upon the principle of the equality of the radiating and absorbing powers of bodies. The apparatus employed consisted of a horizontal brass tube, which could be heated red hot by means of a row of burners, and served to conduct the gases and vapors to be examined. One end of this tube was turned up vertically so as to form the radiating jet of gas or vapor; the other was connected with a bellows, while by means of interposed branched tubes and other apparatus the air driven through could be previously dried or passed through water at a known temperature: finally, pure aqueous vapor could be employed to form a jet without admixture of air. A thermometer was suspended over the jet so that its temperature could be determined with sufficient accuracy. The heat radiated from the jet of gas or vapor was allowed to fall upon one surface of a thermo-pile provided with conical reflectors and placed within a double chest of card-board. The effect produced by the radiation of heat from other sources than the jet of gas or vapor was compensated by placing a second and precisely equal source of heat upon the other side of the thermo-pile. With this arrangement a jet of dry air produced by radiation a deviation of the galvanometer which amounted to only three divisions of the scale. When the air was passed through water the deviation remained almost the same. When dry carbonic acid gas was passed through the hot brass tube the deviation amounted to 100-120 divisions, and common illuminating gas gave nearly the same deviation. When air was passed through water heated to 60°-80° C. the deviation rose to 20, but very gradually, while the deviations produced by carbonic acid and illuminating gas were sudden, and rapidly rose to their maxima. When the water boiled so as to produce clouds in the jet of air the deviation exceeded 100 scale divisions, and the same result took place when no jet of air was forced through but the steam alone formed vesicular vapor. When no vesicular vapor was present the galvanometer gave no greater deviation than 20, no matter how much steam might be present.

The greater deviation invariably accompanied the formation of vesicular vapor. From these experiments Magnus concludes that transparent or proper aqueous vapor has a radiating and absorbing power but little greater than that of air, and consequently that the absorptive power of air which contains transparent vapor differs but little from that of dry air. In conclusion the author brings forward an argument based upon the formation of dew. If aqueous vapor were as good an absorbent of heat as Tyndall supposes, dew could never be formed at all, since the vapor necessary for its formation would form a covering over the surface of the earth and prevent radiation. In the tropics, where the atmosphere is loaded with moisture, the dew is very heavy. If the vapor of water possessed as high an absorptive power as Tyndall attributes to it, only a small portion of the heat radiated from the earth could reach the clouds, and the effect of clouds in preventing the formation of dew could not be explained. The conclusions of Frankland in regard to the ice period, and of Tyndall for certain climatic phenomena, based upon the absorptive power of aqueous vapor, remain unchanged if we substitute vesicular vapor. The author further cites the experiments of Cooke and Secchi in regard to the absorption of light by aqueous vapor as shown by the spectroscope, a few dark lines being produced which scarcely diminish the total intensity of the light.-Pogg. Ann., cxxvii, 613.

W. G.

2. On some new forms of electrical apparatus.-TÖPLER and HOLTZ have described independently, but at about the same time, new forms of electrical machines which may be regarded most simply as rotating electrophori. Töpler's machine, which is the simpler of the two, consists essentially of a circular plate or disc of thin vulcanized rubber, gutta percha or glass, mounted upon a vertical axis and caused to rotate rapidly by means of a band and wheel. The disc is coated upon each side with two segments of tin foil, a free space being left between the segments, while the coatings are connected over the edge of the disc by strips of foil. A piece of hard rubber forming a segment of a circle is then excited by friction and placed near and parallel to the lower coated surfaces of the revolving disc. This lower surface becomes electrical by induction, the opposite electricity being driven over the edge to the upper surface of the plate. As the plate revolves, one under segment of tin foil is removed from the inductive action of the excited surface, and the second becomes parallel to it, when the free electricity is decomposed as before. Two isolated conductors are placed above and parallel to the disc, and each carries at one end a light spring or strip of tin foil which rests upon the upper surface of the disc. The two strips are so arranged that as the disc revolves one strip is just leaving a segment of tin foil as the other is brought into contact with it. In this manner the electricity driven to the upper surface is first carried off by one conductor, while the electricity retained upon the lower surface at first, as the plate revolves, passes to the upper surface and is drawn off by the second conductor. The same process then takes place with the second coating, and so on alternately. It will be seen that so far the apparatus is exactly equivalent to an electrophorus, and that the action, though powerful at first, must diminish rapidly as the inductor loses electricity. To remedy this

difficulty a second but smaller disc of glass is placed on the same axis, coated with tin foil in the same manner and provided with a similar inductor and similar conductors. This second inductor is connected with one pole or conductor of the upper and larger plate. Of the two similar conductors belonging to the lower plate, one is connected with the earth while the other is connected with the inductor of the upper plate. In this manner, as the discs rotate, the earth furnishes a constant supply of electricity, and the action of the machine is remarkably powerful. Holtz's machine depends upon similar principles, but could hardly be made intelligible without figures. Several of them have already arrived in this country. A simpler form of apparatus of the same kind has since been described by Bertzch. All these instruments appear to be very much more powerful than plate electrical machines of the same size, and they have the advantage of working with but a small application of force.— Pogg. Ann., cxxv, 469; also Holtz in Pogg. Ann., cxxvii, 320; Bertzch in Cosmos, No. 7, 1866.

W. G.

3. On nitrites of cobalt and nickel.-O. L. ERDMANN has described a series of double nitrites which, while not wanting in interest from a theoretical point of view, are of some importance in analytical chemistry. Nickel gives, with potash and nitrous acid, a soluble double salt, crystallizing in brownish-red octahedrons and having the formula 2KO, NO,+ NiO. NO, as already found by Lang and Rammelsberg. When a solution of this salt is mixed with one of chlorid of calcium, or when nitrite of potash is added to a solution containing both nickel and calcium, a yellow crystalline precipitate is formed which is very slightly soluble in cold but much more soluble in hot water. The solution is green, but the salt is always more or less decomposed. When the salt is formed slowly it crystallizes in well-defined regular octahedrons. Its constitution is represented by the formula

NiO

CaO, NO,+NIO.NO,+KO, NO, or CaO 3NO,.

ко

The corresponding barium salt has been described by Lang. It is also very slightly soluble in water, and crystallizes in microscopic cubes with octahedral faces. The strontium salt forms reddish-yellow crusts consisting of microscopic cubes. Cobalt forms precisely analogous compounds. The triple nitrite of cobalt, potash and lime, forms a blackgreen crystalline precipitate. The salts of cobalt with barium and strontium, have a still more beautiful green color, but like the calcium salt are decomposed by washing. The ammonia nitrite of nickel, which Erdmann terms nitrite of diamin-nickel, forms small cherry-red brilliant crystals having the formula 2NH,. NiO, NO,, and easily decomposed. Fischer's nitrite of cobalt and potash, which according to Stromeyer has the formula Co,203.2NO,+3KO, NO, is, according to Erdmann, a mixture of two different salts, one of which is formed in an acid and the other in a neutral solution. The salt formed in a neutral solution bas 3CoO the formula 3KO

6NO+HO. It is a yellow crystalline powder composed of microscopic cubes. The author has satisfied himself that no absorption of oxygen takes place during the formation of this salt,