602 



SCIENCE 



[N. S. Vol. XLHI. No. 1113 



by-product of the government seal boneyard, 

 was $423,000. The bones of 10,000 to 12,000 

 seals might have been deposited each year 

 since to increase the store of " government- 

 owned fertilizer," but the fur-seal law has 

 prevented the secretary of commerce from 

 killing them. In addition to the loss of the 

 bone, there has been the loss in seal skins, 

 which in the meantime have risen to a price of 

 $50 each. Incidentally these seal skins, if 

 they could be taken, would also be valuable 

 cargo for the ships " that may be provided by 

 the pending administration ship purchase bill," 

 and less troublesome than bone to handle. 

 George Abchibald Clark 



materials in a ton of kelp 

 The seriousness of the current shortage of 

 potash gives increased importance to a careful 

 consideration of the American sources of it. 

 The following table gives in pounds the quan- 

 tities of the materials mentioned that are con- 



THE TOXICITY OF BOG WATER 



The writer has found by experiments that 

 filtered bog waters show a precipitate when 

 saturated with ammonium sulphate, disodium 

 hydrogen phosphate, or sodimn chloride. The 

 filtrate from this when freed from the salt by 

 dialysis did not prove toxic in solution cul- 

 tures to the root hairs of Tradescantia, while 

 the untreated bog water did prove toxic. The 

 matter precipitated by these salts is not vola- 

 tile at 100° C. 



Since the specific gravity of bog water is 

 1.000, and its osmotic pressure is very low it 

 seems probable that the substances present in 

 this water are in a colloidal state. The above 

 data tend to confirm this view and suggest that 

 the coUoidal matter may be a large factor in 

 the toxicity of bog waters. 



The waters used were obtained from sphag- 

 num bogs in the Puget Sound region and 

 Alaska. George B. Eigg 



University of Washington 



tained in a ton (2,000 pounds) of fresh kelp. 

 The three species mentioned are the ones that 

 are harvestable in commercial quantities along 

 the Pacific coast of North America. The 

 supply available on the California coast is 

 mainly Macrocystis, that in the Puget Sound 

 region is mainly Nereocystis, while that in 

 southern Alaska is Nereocystis, Macrocystis 

 and Alai-ia. In western Alaska the supply is 

 Nereocystis and Alaria. 



The computations are made from data ob- 

 tained by workers in the United States Bu- 

 reau of Soils, the University of California and 

 the University of Washington. 



The algin here reported is the adhesive 

 material that can be dissolved in sodium car- 

 bonate and precipitated with acids. The crude 

 fiber reported was approximately half cellulose. 



George B. Eigg 



University of Washington 



EXHIBITION OF THE ROYAL PHOTOGRAPHIC 

 SOCIETY 



To THE Editor of Science: The sixty-first 

 annual exhibition of the Eoyal Photographic 

 Society wiU be held as usual in August and 

 September of this year. In order to facilitate 

 the collection and forwarding of scientific ex- 

 hibits I have been appointed one of the judges 

 in the scientific section of the forthcoming ex- 

 hibition and have made arrangements to re- 

 ceive photographs from American workers and 

 to forward them to London, thus relieving the 

 photographer of all difficulty and expense. 



I should be very glad to hear from any 

 American photographer who wishes to enter 

 photographs in the scientific section of the ex- 

 hibition of the Eoyal Photographic Society 

 and to forward him an entry form. 



For some years now the American exhibit in 

 the scientific section has been a comprehensive 

 one and of great interest to European workers 



