248 



SCIENCE 



[Vol. VI., No. 137. 



region, the nebula had presented its usual ap- 

 pearance, and that here was nothing stellar 

 about it. By June 10 the star had vanished ; 

 but the cluster seemed to shine with unusual 

 brilliancy, and a marked central condensation. 

 Since that time the object has been closely 

 watched by Schmidt at Athens, who examined 

 it at least one thousand times between 1861 

 and 1877; but the star has never been seen. 

 Spectroscopically observed b}^ Col. John Her- 

 schel, on April 13, 1868, the nebula exhibited 

 a continuous spectrum. 



The only other similar case that I am aware 

 of, is the variable R Monocerotis discovered 

 by Schmidt in 1861. It is situated in the 

 southerly end of a faint cometary nebula. 

 The phenomena presented are, however, much 

 less striking, more resembling those of an 

 ordinary variable star. Schmidt has seen it as 

 bright as 10th magnitude. I have never found 

 it brighter than the 12th ; and ordinarily it is 

 invisible, or very near the limit of visibility 

 (which I arbitrarily assume to be 13th mag- 

 nitude) of the six and one-fourth inch Clacey 

 refractor. 



The future developments in regard to the 

 new star in the Andromeda nebula will be fol- 

 lowed by astronomers with the greatest interest. 

 This event, too, should draw attention to a 

 subject of observation which has been entirely 

 neglected. Hitherto, the question oJ' nebular 

 variation has been confined almost entirely to 

 examination of evidence of fluctuation in the 

 apparent brillianc}' of the nebulous appear- 

 ance itself. But the peculiarities in telescopes 

 and observers, and variations in personal, 

 atmospheric, and other conditions, render it 

 ver}^ difficult to decide upon such evidence. 

 Consequentl3S while there are one or two 

 nebulae in which, perhaps, a change appears 

 somewhat probable, the subject is surrounde<i 

 with uncertainty and difficulty. A more prom- 

 ising field, however, is opened in the exami- 

 nation of known nebulae to detect the exist- 

 ence, and estimate the brightness, of stellar 

 nuclei ; since we have satisfactory means of 

 comparison and measurement of this kind. 

 Fortunatel}^, this is a kind of observation 

 which needs for its proper prosecution only 

 an ordinary telescope. In the investigation 

 of the variable stars, Argelander's method of 

 observation has proved, in precision, con- 

 venience, and fruitfulness, superior to any 

 photometric apparatus yet devised. A new 

 application of it is here suggested, which, it is 

 hoped, will give employment to some of the 

 idle telescopes in the hands of amateurs. 



Cambridge, Sept. 7. S. C. ChANDLER, JuU. 



THE ASSOCIATION OF OFFICIAL AGRI^ 

 CULTURAL CHEMISTS. 



The second meeting of this association was held 

 in Washington, Sept. 1-2. In the absence of the 

 President, Prof. S. W. Johnson of New Haven, Dr. 

 H. C. White of Georgia presided. Delegates were pres- 

 ent from most of the states exercising control or 

 inspection of fertilizers. A number of other chemists 

 interested in agricultural analysis, but not occupying 

 oflQcial positions, were present, and took part in the 

 proceedings. 



Commissioner Colman, in an introductory address, 

 spoke of the importance of securing uniformity of 

 action among chemists, not only in the analysis of fer- 

 tilizers, but also in all analytical processes pertaining 

 to agricultural chemistry. He referred to the impe- 

 tus which scientific agriculture had received from the 

 labors of Liebig and his successors. He believed 

 that all experimental agricultural work should be ac- 

 companied by careful chemical control, without which 

 its full value could not be secured. He thought that 

 the general government ought to co-operate with the 

 state governments in passing the most stringent laws 

 against the adulteration of foods. Continuing, he 

 said, "In so simple a matter as the adulteration of 

 milk, it would be hard to secure a conviction in a 

 court of justice for any person practising it, because 

 of the absence of any oflficial standard by means of 

 which the extent of the adulteration could be meas- 

 ured. It should be the object of the chemical control 

 of agriculture, not only that abundant crops should 

 be produced, but also to see that the products of the 

 fields should be delivered to consumers free of any 

 cheap or deleterious adulteration. The frauds that 

 are practised upon the public in adding cheap, and 

 frequently harmful, ingredients to the food we eat, 

 ought to be exposed in no uncertain way. To such 

 an extent is the a4ulteration of batter, and ihe man- 

 ufacture of a counterfeit article, carried on, that the 

 great dairy interests of our nation are now almost 

 prostrate. Many an honest producer has become 

 bankrupt in trying to keep up with his unscrupulous 

 competitor." 



After the commissioner's address, Mr. E. H. Jen- 

 kins, chairman of the committee on the method of 

 estimating phosphoric acid, reported the results of 

 the labors of tbe committee during the past year. 

 He gave first a review of all the new processes which 

 have been suggested for determining phosphoric 

 acid. Samples of various kinds of phosphates had 

 been sent out to the different members of the associ- 

 ation in sealed packages, and the results of the analy- 

 ses had been received and tabulated. In general, the 

 agreement of the analyses was very satisfactory, es- 

 pecially in the amount of total phosphoric acid esti- 

 mated. In the so-called reverted phosphoric acid, or 

 phosphate soluble in solution of citrate of ammonia, 

 the agreement was not so perfect. Nevertheless, the 

 deviations from the mean were not any greater than 

 could be expected from the nature of the material 

 analyzed, and the diflQculty of securing perfectly uni- 

 form results with the reagent employed. The com- 



