260 Dr. Thomson on Sanatory Report. 



readily removed to wherever it might be wanted, and also of performing 

 this kind of work more advantageously than the ordinary kilns. If the 

 furnace were built on a plate of iron, the kelp made in this manne? 

 and from these materials would bring the very highest market price, higher 

 than any at present obtained, and would undoubtedly command the atten- 

 tion of chemical manufacturers to the exclusion of an inferior article. 

 The salt which would be obtained by the lixiviation and concentration of 

 such ashes would be worth from £10 to £12 per ton to the chemist, even 

 at the present very low price of iodine. 



I can only refer briefly to my concluding topic, not that I con- 

 sider it by any means of minor importance, but simply because I have 

 already occupied too much of your space. I allude to the application of 

 kelp, or of kelp waste to agricultural purposes. Much has been already 

 said and done on this subject, but I believe there is much still unsaid. In 

 the Highlands the wreck is plentifully taken from the shores and spread 

 on the grounds as a manure, where, indeed, it constitutes their main 

 ground of hope for the success of their crops. The utility of this practice 

 is known and acknowledged on all hands, and we cannot but suppose that 

 the like application of kelp would be attended in many cases with success. 

 I would press this upon the attention of farmers and agriculturists in all 

 parts, but chiefly in inland districts, where, by a careful application of 

 kelp for green crops, a native manufacture would be fostered, the condition 

 of a large class of our countrymen bettered, and expensive quack manures 

 to a great extent become extinct. The kelp for this purpose would require 

 to be ground, and in this state, and before application to the soil, if it were 

 mixed with 5 to 6 per cent, of a salt of ammonia, it would equal, nay sur- 

 pass any guano in productiveness, and certainly supersede it in every way. 



I have refrained in the present paper from entering upon the chemical 

 composition of kelp, as it is my intention to lay a few details before you 

 on that subject in a subsequent paper, when, I shall take the opportunity 

 of adding what I may at present have neglected, and which would have 

 made this communication, it may be, of an unreasonable length. 



29th March, 1848. — The President in the Chair. 



Messrs. William Kerr and David Burgess, were admitted members. 



Dr. R. D. Thomson read his " contributions to a sanatory report on 

 Glasgow." In this communication, the division of infectious diseases, 

 into two classes, was alluded to. One of these classes is produced by 

 emanations from the earth, or by particular conditions of the atmosphere, 

 and is not contagious or communicable from one individual to another, 

 It is typified by ague and Asiatic cholera. The second class is produced 

 by a poison generated in the human system, and is communicated by the 

 contact with the blood by a poison. The types of this class are small 



