428
T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y
(3,200pounds moisture-free wood) of the valuable products and the value of each is thus given by Veitch and Merrill: Refined wood turpentine, 6 gallons, at $0.40.. . . . . . . . . . . Pine oils, 7 gallons, at $0.35.. . . . . . . . . . . . . . . . . . . . . . . . Rosin spirits, 1 1 gallons, at $0.20.. . . . . . . . . . . . . . . . . . . . Rosin oils, 40 gallons, at $0.35.. . . . . . . . . . . . . . . . . . . . . . . Phenoloids, 12 gallons, at $0.06... . . . . . . . . . . . . . . . . . . Crude methyl alcohol, 3.5 gallons, at $0.35. . . . . . . . . . . . Unbleached pulp, 1,440 pounds, at $0.0175.. . . . . . . . . . . . Total.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Vol. 5 , No. 5
In this case-at Fontenoy de Comte-the tar was spread so close to the trees that it prevented the water from getting to the roots.
2.40
2.45 2 .20 14.00 0.72 1.20 25.20 4 8 . *7
Thus products worth $48.17are made from wood which costs from $2.00 to $4.00 delivered a t the works. The values given are approximate wholesale values a t the plant, and are said to hold, approximately, for good average lightwood, except as to refined wood turpentine, which should run higher than reported. All the products are said to be of good quality, the pulp making a good strong brown wrapping paper, quite similar to that now selling a t from 3 to 4 cents per pound. It is believed that such a combination as that mentioned offers the most p ofitable use of refuse wood and stumps on the cutover pine lands of the South and West.
PRESSURE FILTERS FOR CLARIFYING TRADE WASTES The clarification of the liquid wastes from a glue factory by means of pressure filters has been tried out by a Gloucester, Mass., firm, and a plant with a capacity of one million gallons per day has been installed a t its works. The wastes are pumped from a basin by a centrifugal pump and passed through pressure filters until the layer of waste which is intercepted by the top surface of the sand has attained a considerable thickness. The water is then drawn off and compressed air is applied to dry the sludge layer and convert it into a flexible cake, which is rolled up and removed through manholes in the filter. After passing through presses, the sludge cake may, it is claimed, be used as a fertilizer. The pressure filters are cylindrical steel drums containing a bottom layer of pebbles and a filling, 30 inches deep, of coarse quartz sand. In drying the sludge layer, in which operation air under pressure is blown down through the filtering medium, forcing the water out, about one hour is required. The filters are operated continuously for 60 working hours at a time, and are then opened up and the detritus is removed. It is needless to remark that the time of the drying process is dependent upon the blower.
THE EFFECTS OF TAR ROADS UPON VEGETATION AND ANIMALS It has been stated that the dust from tarred roads has appeared to be more irritating to the eyes than that from untarred THE HAMMOND WATER METER roads, and in 1910an investigation of this matter was conducted The Hammond meter, designed for use under the exacting in France by Truc and Fleig (Compt. rend., 151,593). I t was ascertained that dust from untarred roads had only the slightest effect when sprinkled on the eyes of animals, and that dust from old tarred roads, from which the coating had more or less disappeared, gave effects little different. However, dust from old tarred roads with a well preserved surface occasioned conjunctivitis and other lesions, while dust artificially produced from such roads gave still more severe effects. Notwithstanding the fact that bituminous vapors have only a slight action upon the eye (Comfit. rend., 151, 769), the investigations of Truc and Fleig seemed to show that the results corresponded to the proportion of tar, as well as t o the mechanical irritation produced by the dust and to the germs present. Concerning these observations, Baskerville has remarked (N. Y . Med. I., November 30, 1912) that while bituminous dust may rapidly produce various lesions in the eyes, and may leave persistent leucoma, the condition of the eye and the action of sunlight are both predisposing causes. H e noted that the experiments which have been conducted on these points do not, moreover, constitute a n argument against the tarring of roads, for, when tarring is well done, it diminishes the chance of injury to the eyes. I n 1911,Mirande (Comfit. rend., 152, 204) investigated the many substances prepared from coal tar used for preserving wood, destroying moss on tree trunks, as insecticides, etc. He was led to conclude that these all contained creosote and gave off vapors which were destructive to leaves, flowers, shoots, etc., in the same way as coal tar vapors, blackening them and causing death by plasmolysis. Quite recently the statement that the use of tar on roads has an injurious effect on the surrounding trees and vegetation, for which Mirande is held responsible, has been pronounced to be unfounded by German experts. H. F. Fischer has been investigating the matter, and he plans to present his results before the coming International Road Congress, which is to convene in London in June, 1913. I t may also be noted that the conclusions of Mirande respecting tarred roads have been refuted by several French engineers (Ckem. World, 2, IO^), who point out that a large street in Bordeaux has been treated with tar for some years without the slightest damage to the trees bordering the street, and that other towns have also practised tarring without injurious results, though one example is on recQrd where the trees wound a square were destroyed by tar. conditions found in the modern power station, is said to be
