liv REPORT — 1861. 



We must still wait for the application of more perfect instruments, and 

 especially for the careful registering of the appearances of the sun bj' the 

 photoheliograph of Sir John Herschel, so ably employed by Mr. "Warren De 

 la Rue, Mr. Welsh, and others, before we can expect a solution of all tLe 

 problems thus suggested. 



Guided by the same principles which have been so successful in Astronomy, 

 its sister science, Magnetism, emerging from its infancy, has of late advanced 

 rapidly in that stage of development which is marked by assiduous and 

 systematic observation of the phenomena, by careful analysis and presenta- 

 tion of the facts which they disclose, and by the grouping of these in gene- 

 ralizations, which, when the basis on which they rest shall be more extended, 

 will prepare the way for the conception of a general physical theory, in which 

 all the phenomena shall be comprehended, whilst each shall receive its 

 separate and satisfactory explanation. 



It is unnecessary to remind you of the deep interest which the British 

 Association has at all times taken in the advancement of this branch of 

 natural knowledge, or of the specific recommendations which, made in con- 

 junction with the Royal Society, have been productive of such various and 

 important results. To refer but to a single instance, we have seen those 

 magnetic disturbances, — so mysterious in their origin and so extensive in simul- 

 taneous prevalence, and which, less than twenty years ago, were designated 

 by a term specially denoting that their laws were wholly unknown, — traced 

 to laws of periodical recurrence, revealing, without a doubt, their origin in 

 the central body of our system, by inequalities which have for their respect- 

 ive periods, the solar day, the solar year, and still more remarkably, an 

 until lately unsuspected solar cycle of about ten of our terrestrial years, to 

 whose existence they bear testimony in conjunction with the solar spots, 

 but whose nature and causes are in all other respects still wrapped in entire 

 obscurity. We owe to General Sabine, especially, the recognition and study 

 of these and other solar magnetic influences and of the magnetic influence 

 of the moon similarly attested by concurrent determinations in many parts of 

 the globe, which are now held to constitute a distinct branch of this science 

 not inappropriately named " celestial," as distinguished from purely terres- 

 trial magnetism. 



We ought not in this town to forget that the very rapid advance which 

 has been made in our time by Chemistry is due to the law of equivalents, 

 or atomic theory, first discovered by our townsman, Jolin Dalton. Since 

 the development of this law its progress has been unimpeded, and it has had 

 a most direct bearing on the comforts and enjoyments of life. A knowledge 

 of the constituents of food has led to important deductions as to the relative 

 nutritive value and commercial importance of different materials. Water 

 has been studied in reference to the deleterious impurities with which it is so 

 apt to be contaminated in its distribution to the inhabitants of large towns. 

 The power of analysis, which enables us to detect adulterations, has been 

 invaluable to the public health, and would be much more so, if it were 

 possible to obviate the difficulties which have prevented the operation of 

 recent legislation on this subject. 



We have another proof of the utility of this science in its application to 

 medicine; and the estimation in which it is held by the medical profession 

 is the true index of its value in the diagnosis and treatment of disease. The 

 largest developments of chemistry, however, have been in connexion with 

 the useful arts. What would now be the condition of calico-printing, 

 bleaching, dyeing, and even agriculture itself, if they had been deprived of 

 the aid of theoretic chemistry ? 



