SCIENCE. 



367 



We recently called attention to a report made by 

 Professor Leeds to the Chemical Society, of New 

 York on the adulterations of certain articles of food. 

 The tenor of the report was to show that food 

 products in general were unadulterated and pure, 

 and to cast ridicule on those who asserted to the 

 contrary. Among other specific statements Prof. 

 Leeds stated that he had made a special examination 

 of sugar syrups, and asserted that the result of his in- 

 vestigations showed, that they were free from any ad- 

 mixture of glucose. 



Side by side with Prof. Leeds' report we gave the 

 statement of Prof. Wiley that 500 tons of glucose 

 was made daily in the United States, the bulk of 

 which was used for adulterating cane sugars, and 

 that the glucose of commerce as sold in the Western 

 States was largely composed of syrup made from 

 starch. 



We publish in this issue a letter from Prof. Wiley 

 in confirmation of his report, stating that the man- 

 ufacture of a sugar, which is a mixture of glucose 

 and cane sugar, is carried on in New York city or 

 its vicinity. 



AMYLOSE. 



As a thousand tons of sugar made from starch 

 will within a few months be placed on the market 

 daily, half that amount being already the con- 

 sumption of that article of commerce, it appears de- 

 sirable to make use of some name by which this sub- 

 stance may be known and at the suggestion of Prof. 

 Wiley, we propose " Amvlose " as an appropriate 

 term. 



Amylose will include all varieties of syrups and 

 sugars manufactured from starch. (I. at. Amy In 111, 

 Starch). 



NOTE ON PHOTOGRAPHS OF THE SPECTRUM 

 OF THE COMET OF JUNE, 18S1. 



By Professor Henry Draper, M. D. 



The appearance of a large comet has afforded an op- 

 portunity of adding to our knowledge of these bodies by 

 applying to it a new means of research. Owing to the 

 recent progress in photography, it was to be hoped that 

 photographs of the comet and even of its spectrum might 

 be obtained and peculiarities invisible to the eye detected. 

 For such experiments my observatory was prepared, be- 

 cause for many years its resources had been directed to 

 the more delicate branches of celestial photography and 

 spectroscopy, such as photography of stellar spectra and 

 of the nebula;. More than a hundred photographs of 

 spectra of stars have been taken, and in the nebula of 

 Orion details equal in faintness to stars of the 1 4.7 mag- 

 nitude have been photographed. 



It was obvious that if the comet could be photographed 

 by less than an hour's exposure, there would be a chance 

 of obtaining a photograph of the spectrum of the coma, 

 especially as it was probable that its ultra-violet region 

 consisted of but few lines. In examining my photographs 

 of the spectrum of the voltaic arc, a strong band or 



group of lines was found above H, and on the hypothesis 

 that the incandescent vapor of a carbon compound exists 

 in comets this band might be photographed in their spec- 

 trum. 



Accordingly, at the first attempt, a photograph of the 

 nucleus and part of the envelopes was obtained in seven- 

 teen minutes on the night of June 24th, through breaks 

 in the clouds. (In succeeding occasions, when an expos- 

 ure of 162 minutes was given, the tail impressed itself to 

 an extent of nearly ten degrees in length. 



I next tried by interposing a direct vision prism be- 

 tween the sensitive plate and object glass to secure a 

 photograph which would show the continuous spectrum 

 of the nucleus and the banded spectrum of the coma. 

 After an exposure of eighty-three minutes, a strong 

 pic'ure of the spectrum of the nucleus, coma and part of 

 the tail was obtained, but the banded spectrum was over- 

 powered by the continuous spectrum. 



I then applied the two-prism spectroscope used for 

 s'ellar spectrum photography, anticipating that although 

 the diminution of light would be serious after passing 

 through the slit, two prisms and two object glasses, yet 

 the advantage of being able to have a juxtaposed com- 

 parison spectrum would make the attempt desirable, and 

 moreover, the continuous spectrum being more weakened 

 than the banded by the increased dispersion the latter 

 would become more distinct. 



Three photographs of the comet's spectrum have been 

 taken with this arrangement with exposures of 180 min- 

 utes, 196 minutes and 228 minutes, and with a compari- 

 son spectrum on each. The continuous spectrum of the 

 nucleus was plainly seen while the photography was in 

 progress. It will take some time to reduce and discuss 

 these photographs and prepare the auxiliary photographs 

 which will be necessary for their interpretation. For the 

 present it will suffice to say that the most striking feature 

 is a heavy hand above H which is divisible into lines and 

 in addition two faint bands, one between G and h and 

 another between h and H. I was very careful to stop 

 these exposures before dawn, fearing that the spectrum 

 of daylight might become superposed on the cometary 

 spectrum. 



It would seem that these photographs strengthen the 

 hypothesis of the presence of carbon in comets, but a 

 series of comparisons will be necessary, and it is not im- 

 probable that a part of the spectrum may be due to other 

 elements. 



271 Madison Avenue, New York. 



OBSERVATIONS ON SIREDON LICHENOIDES.* 



By Wm. E. Caklin. 



Como Lake is a body of water about two miles and a 

 half in circumference. It has no known outlet, but is fed 

 by a stream of pure spring water about two feet wide and 

 a foot deep, which, continually running, prevents the 

 lake's absorption by evaporation. The lake is quite shal- 

 low and can be easily waded at almost any part, being not 

 more than 10 feet deep in the deepest place that I have 

 been able to find. The bottom of the lake is soft and is 

 covered in most places with grass and weeds. The water 

 is strongly impregnated with alkali, and a large number 

 of cattle are said to have died a number of years ago from 

 drinking it. It is very disagreeable to the taste. The 

 amount of water varies about 14 inches during the year, 

 being highest in the spring from the melting snows, and 

 lowest in the autumn. This is the home of the Siredon 

 lichenoides (Baird). They never enter the stream of fresh 

 water, preferring the alkali water of the lake. They seem 

 to surfer no inconvenience, however, if placed in fresh 

 water. I have caught as many as a hundred and fifty and 



♦From the Proceedings of United States National Museum. 



