October i, 1884.] 



THE TROPICAL AGRICULTURIST 



321 



substitution for gum arabic, he might say that it was 

 almost impossible of late years to obtain this gum of 

 good quality. That which they now obtained made a mucil- 

 age more like that of white of egg than that from good 

 gum. The bean found with the sea wrack was one which 

 was found in the West Indies, commonly calied the asses'- 

 eye bean (Mucuna urens). 



Mr. Cross said it would be very interesting to see Mr. 

 Stanford's results correlated with the main principles of 

 cellulose chemistry. Perhaps the most interesting feature 

 of the algin was tin- presence of nitrogen, but he had 

 not said anything about the products of decomposition 

 of the algin, such as would throw light on the point 

 whether the nitrogen was essentially connected with the 

 carbon molecule which presided over the whole. It would 

 be very interesting to have some information on these 

 points. There was certainly some evidence of its having 

 the general properties of an aldehyde, and, in some respects, 

 it reminded one of the body recently described as oxy- 

 eellulose. A\'henever cellulose was oxidised it yielded these 

 peculiarly gelatinising bodies. It was impossible in a few 

 words to even indicate the enormous field which was opened 

 up for investigation by the discovery of this substance, 

 and he hoped it would be thoroughly taken up. 



Mr. T. Christy said he had brought with him some 

 Eiicheuma speciosa from the western shore of Australia ; 

 and amongst several seaweeds which he had put into com- 

 mercial use, none gave such excellent results in dyeing 

 aud the preparation of mordants. He had had several 

 requests from France to procure further supplies, but 

 though he held out every inducement to the traders on 

 the west coast of Australia to forward this seaweed, he 

 had not succeeded in getting any more. Mr. Greth, in 

 making some experiments with it, and also on some Japinese 

 seaweed, found that it took up 500 times its weight of 

 water, and as a sizing material there was nothing equal 

 to it. He had also tried it in several preparations for 

 damp walls, and found it most effectual both with plaster, 

 lime, and brick walls. Mr. Greth was still working at this 

 subject in Berlin. The use of the algae in combination 

 with shellac was of great importance, as it prevented the 

 extreme brittleness which arose from the use of shellac 

 alone. It was largely used for this purpose in France, 

 where thay were very particular as to the class of sea- 

 weed, and next to that from Australia, the weed from 

 Singapore met with most favour. He had lately, however, 

 received some E. Spinoaa from Borneo, which was even 

 superior to that from Singapore. There was an immense 

 field for the use of seaweed, if a regular supply could be 

 depended upon of these qualities. 



Mr. Lloyd said everyone who had passed a heap of 

 seaweed must have noticed the disagreeable smell which 

 came from it, showing that it was most liable to decom- 

 position, and this was the root of the difficulty of deal- 

 ing with it as food; besides which, few, if any people, 

 knew how to cook it. In "Wales it was largely used fried 

 in oil, and he believed it was also used in London to some 

 extent boiled like greens. He was much surprised to hear 

 that seaweed had been kept in a silo, and retained 80 

 per cent of moisture, knowing its liability to decompose, 

 and the immense difficulty which farmers had found in 

 keeping grass with only 75 per cent of moisture; it would 

 be interesting to know what changes had taken place, and 

 whether the preservation was due to the formation of 

 some acid, or to the presence of salt in considerable quant- 

 ities. Looking to the precipitating power of one of the 

 products Mr. Stanford had obtained, it occurred to him 

 that possibly it might be useful in the purification of 

 sewage, at any rate in the initial operation of throwing 

 down the solid matter, 



Mr. J. M. Thomson said he understood Mr. Stanford that 

 this new substance might be used in photography, and 

 would produce a harder film than gelatine, but he thought 

 there might be a difficulty in easily softening it with 

 water for the purpose of making an emulsion with silts 

 of silver. One point mentioned in the early part of the 

 paper, viz., the affording occupation to the crofters was 

 of great importance. He could speak from experience of 

 the west coast of Scotland, and if by the aid of the sys- 

 tem of telpherage, lately brought forward by Professor 

 Fleeming Jenkin, this industry could be developed, it would 

 be of immense advantage to the inhabitants. If there 



•a 



were more men like Mr. Stanford in that district, in 

 dicating, as he had done, the directions in which the 

 crofters might make their work remunerative, less would 

 be heard of crofters' commissions. 



Mr. Stanford, in reply, said that algin had been tried in 

 photography, but there was one disadvantage about it, 

 that the silver coagulum was not such a strong one as 

 any of the others. What he had suggested for photography 

 was gel use ; it made a good emulsion, and dry plates had 

 been worked with it. With regard to the preservation in 

 the silo, he could only say that the seaweed had been kept 

 for six months, and it was of a kind very difficult to keep 

 containing, very dry, about 35 per cent of salts, aud very 

 liable to rot. It was put into a well-built silo, and after 

 six months was taken up apparently unaltered. He could 

 not say what was the exact change which had taken 

 place, nor did he think this was as yet ascertained in the 

 case of hay or grass. He did not, however, think the salt 

 had anything to do with it; it was a description of sea- 

 weed which, if air got to it at all, became full of bacteria, 

 and rotted very quickly. He might also say that it had 

 been noticed years ago that when a large quantity of this 

 substance was kept under pressure, that which was kept 

 underneath kept very well. He understood Mr. Christy 

 to be referring to the agar agar as the seaweed from 

 Australia which had given so much satisfaction. He had 

 always drawn the line between these three gelatine-pro- 

 ducing species and any other seaweed. Some years ago he 

 investigated all the species he could get hold of, and could 

 not find gelatine in any but the Gelideum corneum and 

 the Ckondrus crispus, and it was somewhat remarkable 

 that neither those or the Australian agar agar contained 

 either iodine or algin. With regard to Mr. Cross's re- 

 marks, he thought that gentleman had already shown that 

 cellulose was sufficiently difficult to investigate without 

 going into any nitrogenous substances. He had placed 

 algin amongst the albumens and gelatines, and though he 

 had made a great number of experiments on the decom- 

 position products of it, he had not yet arrived at any 

 satisfactory conclusions such as he could lay before a scient- 

 ific society. This substance had not been known quite so 

 long as gelatine and. albumen, and yet the chemistry of 

 both those substances was in almost as unsatisfactory a 

 state as that of algin. He had not tried whether textile 

 fabrics treated with this material would be less combust- 

 ible, but probably they would be from its containing soda. 

 As to the odour of the Enteromorpha compresset, he had not 

 the slightest idea what it came from, any more than he 

 had what caused the odour of the sea, which again would 

 form an interesting subject for investigation to any young 

 chemist who liked to devote his lifetime to it. As to the 

 important question of the deep-sea algae, and the stenophylla 

 which he had given as containing more iodine than the 

 deep-sea tangle, although it grew higher up, the reason 

 was that the stenophylla varied very much in composition ; 

 there was no plant he was acquainted with which varied 

 so much in the amount of iodine it contained. In fact, 

 all the seaweeds varied very much according to the time 

 of year, the age of the plant, and other circumstances. 

 The Laminaria digitata, both the stem and the frond, al- 

 most always contained a definite amount of iodine, and 

 though in this case the stenophylla had come out with the 

 largest percentage, it might easily have been the other 

 way. "With regard to the use of seaweed as food, it was 

 a remarkable fact that in Japan they were used with a 

 large amount of salts in them — as much as 30 per cent 

 when they were sent into the market. He considered that 

 in isolating the algin, we obtained the whole food value, 

 and the whole of the nitrogen of the plant. He was much 

 obliged to Mr. Holmes for the diagrams and specimens he 

 had lent him, and would draw special attention to a spec- 

 imen of giant algse from the Falkland Islands, one of 

 which was supposed to be the longest plant in the world, 

 growing sometimes to the length of 1,500 feet. 



The Chairman said this paper was a most interesting 

 one, and there were many points in which it might be 

 very profitably discussed if time allowed. He could but 

 congratulate Mr. Stanford on his perseverance with this 

 subject, for he must have had a great many things to 

 damp his ardour. Some years ago he (the Chairman) had 

 an opportunity of going over the North British Chemical 

 Works, where Mr. Stanford's process of distillation was 



