September 3, 1886.] 



SCIENCE. 



219 



and this product by the price of stewing exchange, 

 in United States money {E), or SxdxE, and uses 

 the computed denominator 106.560. The value of 

 a legal-tender dollar and of other silver coins is 

 obtained by other denominators given, — thus, for 



the dollar, g^^j. On the 6th of August, with 



silver worth 42d. per ounce in London, our silver 

 dollar was worth in gold bullion 71.21 cents, our 

 trade dollar (full weight), 75.505 cents, and our 

 subsidiary coin, 68.7 cents to the dollar. 



' Recent results in the sorghuQi sugar industry' 

 was the title of a paper by Dr. Peter Collier, of 

 Washington. Numerous comparisons were made 

 between tests of sugar-cane and sorghum, favora- 

 ble to the latter as a sugar-producing plant. As 

 an illustration, 73 approved varieties of sugar- 

 cane grown upon Governor Warmouth's planta- 

 tion in Louisiana being examined, averaged 185 

 pounds of available sugar to the ton of cane. 

 Similar examinations of sorghums by Dr. Collier 

 and Professor Wiley, at the U. S. department of 

 agriculture, including over one hundred varieties, 

 showed the available sugar, per ton of cane, rang- 

 ing from 177 to 199 pounds. The sorghum also, 

 on the average, produced a lower per cent of 

 glucose and of rejected solids than the sugar-cane, 

 this being also in its favor. As a rule, sorghum 

 yields a less product per acre than. cane, but the 

 cost of cultivation per acre is enough less to more 

 than compensate. The great cost of an acre of cane 

 is well known, while sorghum costs not over ten per 

 cent more than a crop of Indian corn of the same 

 area. Chemical results and the manufacture of 

 sorghum sugar, both on an experimental scale and 

 commercially, in Kansas and New Jersey, are such, 

 to date, as to offer every encouragement to this in- 

 dustry. Dr. Collier thinks the record justifies his 

 prediction of the production of sorghum sugar in 

 this country, in the near future, at a cost not ex- 

 ceeding one cent a pound. Dr. Collier also pre- 

 sented, in the form of graphical charts, with 

 brief verbal explanations, ' Statistics relating 

 to the dairy industry.' Compiled from official 

 figures, these charts conclusively disprove the 

 claim that agricultural land and labor, live stock 

 and products, including butter, have suffered de- 

 preciation at all disproportioned to the recent 

 general skrinkage in values, because of the intro- 

 duction of oleomargarine and other butter sub- 

 stitutes and imitations. On the contrary, the 

 number and value of milch cows in this country, 

 and of their pure products, are steadily increas- 

 ing ; and there is now more and better butter 

 made and consumed in America than ever before, 

 while its price, compared with most food prod- 

 ucts, has been strikingly well sustained. 



' The theory of rent, and its practical bearings,' 

 was discussed by Edward T. Peters of Washing- 

 ton, and with such communistic leanings as to 

 meet little approval. 



Mrs. John Lucas, of New Jersey, entered a pa- 

 per upon silk culture, which was received and 

 assigned a place on the programme, but the author 

 failing to appear at the appointed time, the paper 

 was read by title only. 



PROCEEDINGS OF THE SECTION OF MA TH- 

 EMATICS AND ASTRONOMY. 



So MANY important papers were presented in 

 this section, that we cannot even mention them 

 all. Professor Rogers presented two papers, one 

 on the best form of chronograph, and the other, 

 with Anna Winlock, on ' The limitations in the 

 use of Taylor's theorem for the computation of the 

 precessions of close polar stars.' 



The next paper was by Professor Doolittle, of 

 Lehigh university, upon a ' Change in the latitude 

 of the Sayre observatory.' In 1877 Professor Doo- 

 little made a zenith-telescope determination of the 

 latitude of this observatory. Nine years later, he 

 now brings forward a new determination of the 

 same latitude, from the same paii's of stars (fifty- 

 seven in number), with about the same number of 

 observations, the two pieces of work being done 

 with the same instrument, by the same observer, 

 and as nearly as ijossible under exactly the same 

 conditions. No two equally thorough and equally 

 comparable pieces of work with the zenith-tele- 

 scope have ever been offered as evidence for or 

 against a change in latitude, and the result is in- 

 teresting. The difference of the two latitudes 

 comes out 



(J)!- <^„ = + 0" .393 ± 0-.063, 



when the probable error of the declinations is used 

 in the weight-coefficients in each case. Or, since 

 the results may be assumed practically free from 

 the errors of declinations, the result is 



,^j -,^2 = -f 0".393 ± 0".045. 



In the remarks that followed. Professor Newcomb 

 stated that to him it only meant that in one or 

 both of these series of observations there was — as 

 with every observer and every instrument — some 

 source of small systematic error which ' no fellow 

 could find out.' Mr. Woodward, of the geological 

 survey, an expert with the zenith-telescope, and 

 also in questions of probable error, stated that in 

 the absence of further observations he should hesi- 

 tate to say that the observations themselves really 

 indicated a real change of latitude. 



Dr. Gould read a very interesting historical ac- 

 count of the early attempts at astronomical pho- 

 tography, showing that it originated in this coun- 



