52 REPORT — 1873. 



the shaft under the action of the second wire and contact-breaker will be trans- 

 mitted to the pencil, and cause it to turn in the direction W. through S. to E. 

 instead of the reverse. 



It is necessary to make the fittings so exact that no movement of the shaft 

 can occur without a corresponding motion of the pencil ; otherwise the orientation 

 of the instrument would be rendered incorrect. 



The instrument above described has not yet been constructed ; hence no informa- 

 tion can be given as to battery power necessary to work it. Probably very little 

 would suffice ; for as tlie rotation of both shafts is continuous and in the same sense, 

 the whole actual work of moving the pencils over the paper could easily be per- 

 formed by a small weight or spring suitably arranged. 



On an improved form of OxyJiydrogen Lantern for the use of Lecturers. 

 By C. J. WooDWAKD, jB./S'c. 



The author stated that the form of oxyhydrogen lantern generally used by 

 lecturers was merely the old magic lantern, and this was not sufficient for the many 

 requirements of the lecturer of the present day. What was required was a light 

 lantern which would direct a beam in any direction whatever, and which would 

 not only serve to show photographs and slides, but would do also for exhibiting 

 experiments such as electrolysis of liquids, magnetic curves, cohesion-figures, &c. 



The instrument the author exhibited consists of a small lanteni swinging between 

 two uprights. It can be clamped at any angle ; and as the stand is one capable of 

 rotating, the lantern can be made to project a beam of light in any direction. The 

 stool of the lantern is constructed on the principle of Willis's apparatus for lecturers 

 on mechanics ; and to this is fastened carriers for a table to support a prism or other 

 piece of apparatus. A projecting bar serves to hold the lenses, which slide on the 

 bar and can be turned out of the way in a moment. The lantern was made for the 

 author by Messrs. E. Field & Co., of Birmingham. 



A description of the Instrument, -with woodcuts, will be found in the ' Engineer,' 

 vol. xxxvi. p. 284. 



CHEMISTET. 



Address by W. J. Russell, Ph.D., F.B.S., President of the Section, 



Of late years it has been the custom of my predecessors in this chair to open 

 the business of the Section with an address, and the subject of this address has 

 almost invariably been a review of the progi-ess of Chemistry during the past year ; 

 I purpose, with your leave, to-day to deviate somewhat from this precedent, and 

 to limit my remarks, as far as the progress of Chemistiy is concerned, to the his- 

 tory of one chemical substance. The interest and the use of an annual sun-ey at 

 these meetings of the progress of Chemistry has to a certain extent passed away ; 

 for the admirable abstracts of all important chemical papers now published by the 

 Chemical Society has in a great measure taken its place, and otiers to the che- 

 mical student a much more thorough means of learning what progress his science 

 is making than could possibly be done by the study of a presidential address. 

 Doubtless these abstracts of chemical papers are known to others than professional 

 chemists; but I cannot pass tliem over without recording the great use they have 

 proved to be, how much they have done already in extending in this country an 

 exact knowledge of the progress of science on the Continent, and in helping and 

 in stimulating those who are engaged in scientific pursuits in this coimtry. I 

 believe few gi-ants made by this Association have done more real good than those 

 which have enabled the Chemical Society to publish these abstracts. 



I dwell for a moment on the doings of the Chemical Society ; for I believe in the 

 progress of this Society we have a most important indication of the progress of 



