98 report — 1842. 



by certain meteorological symptoms, which are capable of accurate registra- 

 tion. This view of the matter is, for the sake of the theory of earthquakes, 

 deserving of being tested by meteorological observations : and such observa- 

 tions have accordingly been commenced at Comrie, by means of instruments, 

 sent there in accordance with the recommendation contained in last year's 

 Report, and understood to have been approved of and sanctioned by the As- 

 sociation. At present the barometer and thermometer are observed at Com- 

 rie only twice in the twenty-four hours. It would, however, be evidently 

 desirable to have much more frequent observations, in order that the state 

 of the atmosphere immediately before, as well as immediately after shocks, 

 should be ascertained. The Committee understand that there are two places 

 in Scotland, where, at the expense of the British Association, hourly obser- 

 vations of the barometer and thermometer are now made and registered. 

 The importance of these observations to meteorology is unquestionable ; and 

 it is manifest that great additional value would be given to them were they 

 carried on at Comrie, Avhere they would become subservient to another 

 branch of scientific research. In this view of the matter they are strongly 

 supported by the Meteorological Committee of the Association, whose con- 

 vener (Sir David Brewster) may be with propriety consulted on this subject. 



The Committee have ascertained that proper persons can be found at 

 Comrie, who, under the superintendence of Mr. Macfarlane, would observe 

 the barometer and thermometer every hour in the twenty-four hours, at an 

 expense of 40/. yearly ; and the Committee express a hope that the Associa- 

 tion will enable them to carry this plan into effect. 



On this subject the Committee will only further observe, that they would 

 be glad if some other meteorological instruments could be sent to Comrie. 

 For an anemometer there is an excellent situation, viz. on the steeple of the 

 parish church. It would be very desirable also to have some instrument 

 capable of indicating the existence of any sudden changes in the electrical 

 state of the earth or the atmosphere ; and it is understood that the expense 

 of these instruments is not great. 



V. The Committee have not yet attempted the registration of earthquake 

 shocks occurring in any other part of this country, except Scotland. Else- 

 where the shocks are not so frequent, or so regular in their recurrence, as to 

 warrant the establishment of instruments : at the same time there do appear 

 to be some parts of the country much more subject to shocks than others. 

 For example, the primary districts of Cornwall and Wales have pretty often 

 experienced shocks ; ami if in the course of the following year any are re- 

 peated in these quarters, it may be right to send some instruments there. 



VI. The Committee have finally to report, that the sum of 261. 16*. have 

 been expended by them in the prosecution of their inquiries. 



Report of a Committee appointed at the Tenth Meeting of the Asso- 

 ciation for the Construction of a Constant Indicator for Steam-en- 

 gines, and for the determination of the Velocity of the Piston of the 

 Single-acting Engine at different periods of the Stroke. Members 

 of the Committee : — Eaton Hodgkinson, Esq., F.R.S. ; J. Enys, 

 Esq. ; the Rev. Professor Moseley, M.A., F.R.S. {Reporter). 

 In the conclusion of their last report the Committee stated it to be their 

 purpose, during the present year, to apply the indicator to some of those en- 

 gines whose work is registered by other means, and to compare the result of 

 the two registrations. It is to this comparison that their labours have ac- 



