ON ARTIFICIAL REFRIGERATION. 063 



cess. Protracted presciTation on land or at sea demands ordy moderate 

 care to keep the bait dry. The method of packing can be such as to 

 economize both room and cost, as compared with barrels. The fish used 

 as bait, if properly handled, would retain form, color, and flavor. Xo 

 extraneous material requires to be used in the i)reservation but what 

 can readily be had at the fishing centres. The ai^i)liances necessaiy for 

 this process are — 



First. Cold storage to take in cargoes of fresh bait in bulk. 



Second. Vacuum cylinders for promj)tly drying the cooled bait. 



Third. Suitable canvas and facilities for i)acking in bales of conven- 

 ient size. 



Fourth. On each boat a convenient receptacle or cabin, through which 

 air is made to pass continually at external temperatures by an auto- 

 matic process ; or if a closed nnd dry chamber is more easily secured, a 

 drying-box containing a small quantity of chloride of magnesium or 

 crude chloride of calcium may be employed without any through current 

 of air. Common salt may, in the absence of the chlorides, sufficiently 

 dry the chamber to prevent mould. 



The cold-storage system I have described elsewhere, and I need only 

 dilate on vacuum process of drying. The good to be derived from this 

 is that slower drying is almost sure to be attended with some change in 

 the flavor from the action of the air on the fish. A Sudlow air-pump 

 such as I use for pumping ammonia gas, will create and maintain a 

 vacuum in wrought-iron cylinders with adjustable covers, so that in two 

 or three days from 15 to 25 per cent, of moisture is abstracted from the 

 bait. The less it is dried the better, perhaps, except for keeping-pro- 

 perties, and here is the only question demanding experiment. I would 

 propose a sux>ply in suitable boxes of bait dried to the extent of 15, 20, 

 and 25 per cent., and if the abstraction of the smaller amount of moist-- 

 ure were not inconsistent with preservation, in bales enclosed in a drying- 

 chamber, it would be useless expense and an actual disadvantage to 

 attempt further desiccation. 



The barrel system of packing would favor mould, and thus affect the 

 flavor and freshness of the bait ; but coarse canvas, admitting of the 

 escape of moisture, however slight this may be, will constitute a solid and 

 sufficient covering for the bait. My experience as to packing the carcasses 

 of mutton and quarters of meat, to hang them up in any convenient place 

 where they can be kept dry on shipboard, indicates that with the most 

 ordinary precautions the bait can thus be stowed away. Should an 

 accident lead to their getting immersed in sea-water, the bales may be 

 hung up like sails to dry in the rigging, and will keep sound and sweet 

 at any temperature. 



The chamber or receptacle on the schooner should be under lock and 

 key and under the skipper's control. The only condition required is 

 dryness, but if the regulations, as to the maintenance of purity and 

 cleanliness in the bait-houses, are not preserved, a sea may be shipped, 



