THE president's addbess. 335 



The carcases are hung vertically, without any packing cloths, 

 on horizontal bars which run on a rail the length of the van, 

 capable of bearing 48 hooks for carrying 12 carcases of beef in 

 quarters, besides 60 double hooks suitable for carrying 5 sheep 

 on each bar, one side of the bar being intended for beef, and the 

 other side of the bar for mutton, according to the consignment. 

 The tare of the van is 50 cwt. ; the load is 90 cwt. in 12 oxen, or 

 60 sheep, or a mixed cargo, as required, and each carcase is sep- 

 arated from the other by strong horizontal laths, to prevent any 

 swinging or motion, and a fresh current of dry cold air circulates 

 freely around the carcases. 



The Great Western Railway Company, has since September, 

 1874, been working one of these meat vans between Windsor and 

 the Metropolitan meat market, Smithfield, which has given com- 

 plete satisfaction to the trade, and last year the van made a trial 

 trip to Barnstaple and back with a cargo, with complete success. 

 I place on the table photographs of the van, and a section of its 

 construction. 



Preservation of iron from rust. 



I now invite your attention to the process of magnetic oxidation 

 of iron, to preserve it from rust, which has been discovered by 

 Mr. F. Barff, professor of chemistry to the Eoyal Academy, and 

 which promises to be an invention of the greatest importance, 

 not only to this county but to the world at large. By this process 

 all kinds of iron work, however much exposed to weather, or even 

 to corrosive liquids may be made practically indestructible. 



To enable you better to understand the value of Professor 

 Barff's invention, let me first describe the operations of the 

 enemy, rust, against which we have to guard. 



When a piece of iron, whether polished or rough, is exposed 

 to the action of moist air or water it begins to rust, and is soon 

 covered with a film of ferrous oxide or protoxide, which consists of 

 56 parts by weight of iron to 16 parts by weight of oxygen. 

 This ferrous oxide, from contact with the atmospheric oxj^gen, is 

 by degrees turned into another oxide, the ferric oxide, or sesqui- 

 oxide, which contains twice 56 parts of iron, to three times 

 16 parts of oxygen. This ferric oxide now begins to act like a 

 sponge, and conveys some of its oxygen to the as yet unoxidized 

 iron beneath it, which thus soon becomes ferrous oxide, again to 

 be converted into ferric oxide, having become accessible to air 



