April 12, 1889.] 



SCIENCE, 



279 



tained a sudden throw of the magnetometer-needle, denoting the 

 magnetization of the iron, followed by a slower motion due prob- 

 ably to the heating effect of the light. While Mr. Bidwell does 

 not consider the results as altogether free from suspicion until all 

 possible disturbing causes have been eliminated, yet, if further re- 

 search confirms the results already arrived at, the experiment is 

 most important. The last year has added many proofs of the fact 

 that light is an electro-magnetic disturbance, but none are so con- 

 clusive as this would be. 



The Purification of Sewage.— Last year we described the 

 plan proposed by Mr. W. Webster for the purification of sewage 

 by electrolytie methods. It has been since tried on a large scale, 

 and with encouraging results. The process is very simple, and is 

 described by the London Electrician as follows : " The color, 

 density, and constitution of the London sewage varies from hour 

 to hour in the most extraordinary manner ; but the first sample to 

 be dealt with was of a light-yellow color, looking something like 

 weak tea with a little milk in it, but, so far as could be seen, it 

 contained very little solid matter in mechanical suspension. This 

 having been poured into a test-jar, a current was passed through it 

 between a pair of iron electrodes, with about six volts electro- 

 motive force. An extremely rapid effect was produced. In less 

 than two minutes the jar was seen to be filled with a flocculent 

 precipitate, which was gradually carried upward by the bubbles of 

 liberated hydrogen. After about three minutes, the electrodes were 

 withdrawn, and the precipitate left to collect at the top. In actual 

 practice, after the effluent has passed into the settling-tank, the 

 precipitate, in the course of about two hours, loses the whole of 

 the entangled hydrogen.; it then sinks to the bottom of the tank- 

 The sludge thus formed is similar to that produced by the chemi- 

 cal processes now in use, except that the electrical method pos- 

 sesses the obvious advantage that the total quantity of material 

 has not been increased by the addition of chemicals." But, besides 

 this precipitation, there is an action on the organic matters in solu- 

 tion which robs them of their unpleasant and harmful properties. 

 In the larger experiments carried on at Crossness, two 20-horse- 

 power engines are used, with an Edison-Hopkinson dynamo. Iron 

 plates are placed in the shoot through which the sewage is dis- 

 charged. In travelling along the shoot, every particle of the sew- 

 age comes in contact with the plates, and finally the whole is 

 received into the settling-tanks. With 27 horse-power, it is pos- 

 sible to treat a million gallons of sewage in twenty-four hours. 

 The consumption of iron in actual working is about two grains per 

 gallon. Taking a town with a daily flow of ten million gallons of 

 sewage a day, — corresponding to a population of about 300,000, 

 — the consumption of iron should not exceed 304 tons per annum, 

 and the steam-plant required would be about 250. This plant 

 takes the place of the mixing-tanks, machinery, and chemicals em- 

 ployed in the chemical process for the purification of sewage ; and, 

 if such electrical plant is designed to meet the peculiar require- 

 ments of the district, it should cost less than any other method, 

 besides precipitating and purifying in one operation. 



Secondary Batteries. — We are informed that in the United 

 States Circuit Court, April 9, Judge Coxe approved of the dis- 

 claimer filed by the Electrical Accumulator Company, and formu- 

 lated the decree and injunction restraining the Julien Electric 

 Company, their officers, agents, and workmen, from further manu- 

 facture, use, or sale of secondary batteries of the Faure type, in 

 which the active material is applied to the support in the form of a 

 paint, paste, or cement. 



NOTES AND NEWS. 



The " Atlantic Pilot Chart for April " says of whirlwinds, 

 water-spouts, and tornadoes, that these phenomena are of the 

 same general character ; and it has been found, that, whenever 

 they occur, it is in connection with a general cyclonic storm of 

 large area. The principles involved in their formation are almost 

 identical with those that determine the formation of a tropica! cy- 

 clone ; that is, great contrasts of temperature and moisture be- 

 tween adjacent layers of air. In the United States and off our 

 coasts they may therefore naturally be expected to occur to the 



southward of a storm-centre, where cold, dry northerly winds blow 

 over and mingle with warm moist air from the southward. That 

 they may occur to the north of a storm-centre, however, under cer- 

 tain conditions, is indicated by a report from Second Officer Madge, 

 of the British steamship " Lake Winnipeg," Capt. Murray. This 

 vessel encountered a severe cyclonic storm Feb. 27, latitude 40° 50 ' 

 north, longitude 56° 48' west ; and at 2.30 p.m., when it was blow- 

 ing a strong gale from the east, a whirlwind was observed moving 

 due west. The barometer was low, and the warm, moist east 

 wind was evidently underrunning a cold, dry current of air from 

 the area of high barometer to the northward, where readings of 

 30.4 inches and upward are reported. It will thus be seen that 

 local conditions of pressure, temperature, and moisture may cause 

 exceptions to the general rule. 



— The lectures to the summer class in botany, of the College of 

 Pharmacy of the City of New York, by Professor Joseph Schrenk, 

 commenced Wednesday, April 10, and will be continued every 

 Wednesday until the end of June. By request of several members 

 of former botany classes. Professor Schrenk will also give a course 

 in practical microscopy. 



— The Essex Institute of Salem, Mass., was organized March i, 

 1848, under a charter granted by the Legislature in February of 

 that year, having for its objects the collection and preservation of 

 whatever relates to the geography, antiquities, and civil and eccle- 

 siastical history of Essex County ; the formation of a cabinet of 

 natural productions in general, and more particularly those of the 

 county ; the promoting a taste for the cultivation of choice fruits 

 and flowers ; its three departments then being history, natural his- 

 tory, and horticulture. The scope of the institute has been from 

 time to time enlarged, and there are now departments of history, 

 science, literature, art, and horticulture. The library of the insti- 

 tute, which in 1848 numbered fifteen hundred volumes, now num- 

 bers fifty-one thousand volumes, and embraces all the departments 

 of literature, but is mostly useful for reference. A reading-room 

 is the latest addition to the library department, and this is well 

 supplied with historical, scientific, and art periodicals, besides the 

 usual magazine literature of the day. The museum of the institute 

 now contains a large and valuable collection of antiquarian and 

 historical relics, portraits, paintings, engravings, medals, coins, 

 paper currency, manuscripts, etc., and is in process of systematic 

 arrangement. The scientific collections, which before 1867 had 

 grown to be so large and of such value that it was impossible for 

 the institute at that time to bear the expense of properly caring for 

 and exhibiting them, were, by agreement entered into between the 

 institute and the trustees of the Peabody Academy of Science in 

 May, 1867, deposited with the last-named institution, where, prop- 

 erly labelled, arranged, and preserved, they are made available to 

 the public, and form an attractive feature of the academy's museum 

 at East India Marine Hall. The publications of the institute regu- 

 larly issued are the Historical Collections, which have now reached 

 Vol. XXV. ; The Bulletin, which has reached Vol. XXL, and con- 

 tains records of the regular meetings and field-meetings of the 

 institute, and special papers on scientific subjects; the Annual Re- 

 port ; besides occasional monographs, etc. The rooms of the in- 

 stitute contain portraits of the officers of the Essex Historical and 

 Essex County Natural History Societies, the forerunners of the 

 institute ; old prints ; silhouettes ; a great number of interesting 

 relics ; historical portraits by Copley, Smibert, Trumbull, and oth- 

 ers ; antique furniture ; local relics ; and military costumes. A 

 fire-proof room holds the large and invaluable collection of manu- 

 scripts. The meetings of the institute are held on the first and 

 third Mondays of every month. During the winter months, papers 

 are read ; and field-meetings are held throughout the county every 

 summer for scientific and historical investigation and discussion. 

 Without considerable endowments in the past, the institute has 

 been able to do for the civil history and archajology of Essex 

 County — and no other county in America offers a better field for 

 such research — what has been so well done for the natural history 

 of the county, a cherished object of the institute, by the well- 

 equipped and earnest workers of the Peabody Academy of Science. 

 With largely increased facilities and resources, which it owes to the 

 general appreciation of its work, it is now ready to go forward, as 



