March 2, 18S3.] 



8CIENCE. 



115 



WEEKLY SUMMARY OF THE PROaRESS OF SCIENCE. 



ASTRONOMY. 



The great comet of 1882. — Mr. E. H. Tucker, 

 jun., of the Dudley observatory, gave a brief account 

 of his observations, beginning Sept. 29, and followed 

 during October and November by a series of twenty 

 complete comparisons with stars, the accurate places 

 of which are to be obtained by the meridian circle 

 of the observatory. Positions of the comet depend- 

 ing upon star places from catalogues of old observa- 

 tions have been, however, used for orbit work; five 

 made here having been telegraphed by request to the 

 Cambridge observatory and used for the ' normal 

 place orbit,' the best that has appeared. Mr. Tucker 

 showed the similarity of the elements of this orbit to 

 those of others, notably those of 1843 and 18S0. The 

 best theoretic orbits, however, show that this cannot 

 be a comet of short period, and consequently not a 

 return of either of those above referred to. He also 

 gave the results of measurements of the head and tail 

 made at the observatory, and described the changes 

 noted in the structure of the former; also some of 

 the results of spectroscopic work elsewhere, showing, 

 among other things, distinct sodium bands in the 

 spectrum. 



In answer to questions raised in the discussion, Mr. 

 Tucker gave the perihelion distance of the comet as 

 probably within 500,000 miles ; and stated that the 

 form of the orbit is probably an ellipse, but very 

 nearly a parabola; also, that the comet is evidently 

 to a great degree self-luminous ; and, further, that the 

 comet's motion was not affected by its near approach 

 to the sun, — unless, perhaps, retarded by a solar at- 

 mosphere, — for the obvious reason that both the 

 comet's motion and the form of its orbit were origi- 

 nally due to the sun's attraction. — {Albany inst.; 

 meeiin,? Jan. 30.) [260 



ENGINEERING. 



Transverse strength of wooden beams. — Prof. 

 Gaetano Lanza, of the Massachusetts institute of 

 technology, described the testing-machine, and exhib- 

 ited its mode of operation by breaking a 6X12 inch 

 spruce beam, eighteen feet span, loaded at the middle. 

 He also reviewed the results of some of his tests, as 

 published in the Journal of the Franklin institute for 

 February, 1883, and deduced a modulus of rupture of 

 from 3,000 to 4,000 pounds per square inch in case of 

 spruce, depending on the quality of the lumber; also, 

 an average modulus of elasticity of 1,293,732. The 

 results of four tests of yellow pine were also given with 

 a time test on a 4X 12 inch yellow pine beam, twenty 

 feet long and loaded at the middle; also, the author's 

 deductions from this time test as to the value of the 

 factor of safety to be employed until a large number 

 of tests shall determine the true value of the modu- 

 lus of elasticity. — {Bost. soc. civ. eng.: meeting Jan. 

 21.) [261 



CHEMISTRY. 



Complex inorganic acids. — Professor Gibbs 

 stated, that, in the further generalization of the 

 results of his investigation of the complex inorganic 

 acids, he had obtained glycero-phospho-tungstate and 

 glycero-phospho-molybdate of barium as well-defined 

 and beautifully crystalline salts ; also dimethyl-arsino- 

 tungstate and dimethyl-arsino-molybdate of sodium 

 in colorless, very slightly soluble crystals. He directed 

 attention to the fact that hypo-phospho-molybdate of 

 ammonium, which he had at first expressed empiri- 

 cally as, — 



24M0O3 . 6PO2 . 6(NH4)2 0-l-7aq,— 



should be written rationally, with 2 additional mole- 

 cules of hydrogen, either as — 



8M0O3 . 2{H2 . PO . OH} 2(NH4)2 + 2aq; 

 or as — 



8M0O3 2{H2 .PO. (ONH4)} . (NH4).2 0-f 3aq. 

 In like manner the phosphoroso-molybdate of ammo- 

 nium described by him with the empirical formula, — 



24M0O3 . 2P, O3 . 5 (NHj), O-t-20aq, — 

 should be written either — 



24Mo O3 . 4 {H. PO. (OH),J5{NH4)2 0-l-14aq; 

 or — 



24Mo03.4!H.PO. (ONHj).,} (NH4), O + ISaq; 

 though of course in each case a partial replacement of 

 (OH) by (ONH4) within the molecule of 2 {H, .PO . 

 O H} or 4 jH . P O . (O H).,} is equally possible. 

 The hypo-phospho-molybdates should be called di- 

 hydryl-phosphino-mobjbdates, and the phosphoroso- 

 molybdates hydryl-phosphino-molybdates. The dimeth- 

 yl-arsino-tungstates and dimethyl-arsino-molybdates 

 evidently belong to the first series. Prof. Gibbs fur- 

 ther stated, that he had found that other modifications 

 of phosphoric acid were capable of forming complex 

 acids with tungstic and molybdic oxides, and that he 

 had obtained very well characterized pyro-phospho- 

 tungstates and meta-phospho-tungstates, as well as 

 the corresponding molybdenum compounds. The 

 molybdico-tungstates, tlie discovery of which he had 

 announced at the last meeting of the club, and which 

 contained molybdic dio.xide (M0O2), formed a particu- 

 larly well defined and beautifully crystallized series. 

 In conclusion, he described in detail the very remarka- 

 ble relations of vanadic pentoxide (VzO., ) to phos- 

 phoric and arsenic pentoxides, and gave an account 

 of the phospho-vanadates and arsenio-vanadates con- 

 sidered as complex acids of an entirely new class. — 

 {Harvard chem. club ; meeting Jan. 23.) [262 



AGRICULTURE. 



A new nitrate ferment. — The reduction, as well 

 as the formation, of nitrates in the soil is now proved 

 to take place under the influence of living organisms. 

 A year and a half ago, while experimenting with 

 infusions of the roots of plants in water. Dr. A. 

 Springer noticed a copious evolution of nitric oxide 

 proceeding from those rich in nitrates ; this seemed 

 to arise from the action of small organisms upon the 

 roots. He then made separate infusions of the roots, 

 stems, and leaves of tobacco, and divided each set 

 into four parts. Fermentation was excited in these 

 by yeast, by urine, by the 'spontaneous method,' and 

 by the newly discovered ferment. Among the fer- 

 ments developed was one which appears to have the 

 property of dissociating the nitrates of the soil. This 

 may be classed among the Anaerobies, but oxygen 

 does not stun it. The ferment obtained from chalk by 

 Bechamp (Bull. soc. chim. [2] vi, 484) is probably the 

 same. Further experiments are in progress. — {Ohio 

 mech. inst. ; sect. chem.. phys. ; meeting Jan. 18.) [263 



Manuring vineyards. — In experiments in three 

 Rhenish vineyards, Wagner finds that manuring with 

 soluble phosphoric acid (100 kg. per hectare) produced 

 in one case no increase, in another case a considerable 

 and profitable increase, and in the third case an un- 

 deniable decrease, of the crop. Addition of potash 

 and nitrogen produced no, or only a very slight, 

 increase. The soil was already rich. No explanation 

 of the unfavorable effect of the phosphoric acid was 

 evident; but experiments on other plants by the same 

 experimenter have shown that excess of phosphoric 



