328 



SCIENCE. 



[N. S. Vol. XXIII. No. 583. 



proportion to the increase in the weight of 

 the marc. 



The results obtained by the writers prove 

 beyond a doubt that the tannin is not de- 

 composed and does not actually disappear 

 in the ripening of the fruit, but that it is 

 converted into an insoluble form within 

 certain specialized cells. No evidence was 

 found of the combination of tannin with 

 any other body in the formation of this 

 insoluble compound. It apparently goes 

 into insoluble form without entering into 

 combination with any other substance. 



At each date of picking sub-samples 

 were ripened- in the laboratory as in the 

 case of fruits previously studied by the 

 writers. The changes occurring on storage 

 were similar to but more rapid than those 

 occurring in the natural ripening of the 

 fruit. Decreases are found in the solids 

 and sugar of the stored fruit while the 

 weight of marc in the fruit is found to 

 increase owing to the tannin becoming in- 

 soluble. 



INDUSTRIAL CHEMISTRY. 



S. W. Parr, chairman. 



The Cotton OH Industry of the South: 

 David Schwartz. 



An interesting account of some of the 

 methods used in purifying cotton oil, illus- 

 trated by samples of the seed, the crude 

 and purified oil and some of the by- 

 products. This will appear in full in the 

 March number of the Journal of the so- 

 ciety. 



A Comparison of Methods used in De- 

 termining Total Soluble Bitumen in 

 Paving Material: L. Avery. (By title.) 



The Duraiility of Cement Plaster: E. H. 



S. Bailey. 



The material sold as cement plaster is 

 made from the gypsum dirt, or 'gypsite,' 

 which occurs throughout many of the states 

 of the central west, in patches of a few 

 score of acres, by heating in a kettle to 



drive off most of the water of crystalliza- 

 tion. This material, mixed with sand, is 

 used in the place of lime mortar for plas- 

 tered walls. In addition to the calcium 

 sulphate and water, it contains considerable 

 calcium and magnesium carbonates, silica 

 and oxides of iron and aluminum. 



A peculiar case of disintegration of the 

 plastered wall of a room in which there was 

 a fan blower for ventilating and warming 

 the building, was investigated. It was 

 noticed that in the upper part of the room 

 the plaster crumbled and fell. The an- 

 alysis of the hard plaster and of that which 

 had fallen showed that the fallen plaster 

 contained about 2 per cent, of moisture, 

 while the hard plaster contained 4.5 per 

 cent. This would indicate that the air 

 which was heated by passing over steam 

 pipes as it came into the fan room, had its 

 capacity for absorbing moisture so much 

 increased that it removed the water from 

 the plaster of the wall, and so the crystals 

 of gypsum disintegrated, and the plaster- 

 ing fell. 



(Published in full in the Trans. Kans. 

 Acad. Sci, Vol. XX.) 



Note on Sampling and Analysis of Coal: 



A. Bement. 



Laid stress on the need of painstaking 

 care in preparing samples of coal for an- 

 alysis, in order to obtain reliable results. 



The Examiiiation of Writing Inks: L. S. 



MUNSON. 



The paper gave the results of examina- 

 tion of a number of writing inks, made for 

 the purpose of determining the suitability 

 of these inks for record purposes. 



Standard Samples of Iron and Steel: J. 



R. Cain. 



A brief statement was made with regard 

 to standard samples of iron and steel which 

 can now be furnished by the Bureau of 

 Standards at "Washington, and charts show- 



