74 POULTRY BREEDING IN 



however, cannot be depended on, as the cover may fit in 

 one place and not in another, or it may not be screwed 

 down so much at one time as another. 



5. Can you at any period ascertain 'whether the jars 

 continue air-tight? 



6. Which are the best air-tight jars, glass or stone 

 iv are? 



These two questions I will endeavor to answer under 

 one head ; and to prevent my being considered to advo- 

 cate one principle more than another from an interested 

 motive, I must inform my correspondents that to most 

 scientific men and poultry-breeders it is well known that 

 egg preserving has formed the study of some of the most 

 eminent chemists in Europe, and that until I published, 

 through The Journal of Horticulture, my simple and 

 yet the only truly effective mode of preserving eggs for 

 any length of time, no satisfactory means had been dis- 

 covered. The intense interest this discovery has created 

 throughout England has induced me to ascertain which 

 of the professed air-tight jars are really so, in order that 

 the public may not lose their confidence in so important a 

 discovery on account of the jars not being to be depended 

 on. Through the kindness of an eminent firm in the 

 pickling trade, I have been enabled to make experiments 

 with the various so-called air-tight jars, few of which 

 really were so, and all without exception objectionable 

 on account of their construction. Then there came 

 another important consideration : how can it be ascer- 

 tained, when the jars are filled, whether they are air-tight, 

 and how long they will remain so ? This, of course, was 

 a perfect imoossibility with the jars as at present manu- 

 factured. 



