REPORT OP THE KEW COMMITTEE. XXXIX 



fragile to stand the work they are designed for. In respect to accuracy, 

 Casella's are also incomparably the best, and he deserves credit for the care 

 witli which they have been made : I cannot report so favourably of the 

 quality of those by Adie, or Negretti and Zambra. I would recommend that 

 for the future the use of metal hydrometers should be altogether discon- 

 tinued. They are four times the price of glass ones, — are generally less 

 accurate, — are more apt to give deceptive results from their greater affinity 

 for grease, — are very liable to pick up small particles of mercury, — and, 

 lastly, if they do get a knock, their indications are rendered ya/se; whereas 

 a glass one is simply destroyed and no harm is done to the observations. 



" 3rd. I have no particular remark to make about the marine barometers 

 by Adie ; they continue to improve in quality and regularity as the maker 

 becomes more familiar with the work. 



" 4th. With regard to punctuality in the delivery of the instruments ; — 

 .there is, I understand, in the contracts, a clause to the effect that if the instru- 

 ments are not delivered at certain dates, the Board of Trade or Admiralty 

 are at liberty to purchase the instruments elsewhere, fhe defaulter to pay 

 any difference in the cost. Now such a penalty might do very well if we 

 had to deal with articles which are to be had at any time of the same quality. 

 As it is, the instruments are not to be had in an emergency by simply sending 

 into the market. I do not mean that barometers and thermometers may not 

 be had in abundance, but we know, from past experience, that they are not 

 of a quality which it would be desirable to give out for accurate observations. 

 Such a penalty becomes therefore practically inoperative. I would suggest, 

 whether a direct pecuniary fine should not be rather imposed in cases of 

 default. If the punctual delivery of the instruments by the makers were 

 rigorously enforced, I should then be able so to arrange beforehand the work 

 of the Observatory, that the verifications should in all cases be proceeded 

 with promptly and regularly. The want of punctuality hitherto has frequently 

 been a source of serious inconvenience to the Observatory. 



" It would, I believe, contribute much to regularity, if the thermometers 

 and hydrometers were sent here in the boxes, just as they are to be delivered 

 to the ships : the additional expense would be very trifling, — perhaps a half- 

 penny on each instrument. 



" I remain, dear Sir, yours faithfully, 



« J: p. Gassiot, Esq., F.E.S." « J. Welsh." 



The following reply has been received from the Board of Trade : — 



" Office of Committee of Privy Council for Trade, Marine Department, 

 4th September, 1855. 



" Sir, — I am directed by the Lords of the Committee of Privy Council 

 for Trade to acknowledge the receipt of your letter of the 31st ultimo, en- 

 closing a copy of a letter from Mr. Welsh, having reference to certain 

 arrangements which he proposes should be made with instrument-makers in 

 the case of future contracts for meteorological instruments; I am to convey 

 to you their Lordships' thanks for the communication, and to inform you 

 that they will adopt Mr. Welsh's suggestions. 



" I am. Sir, your obedient Servant, 



" Douglas Galton, Capt. R.E." 



" John P. Gassiot, Esq., Chairman of the Kew Committee, 

 British Association, Kew Observatory" 



Two portable barometers by Adie, previously compared with the standard 



