346 MASS. EXPERIMENT STATION BULLETIN 260 



(b) Dr. Stevens continued and extended his studies of the relationship 

 of weather to the keeping quality of the fruit, and his incubator tests of 

 keeping quality. 



(c) Dr. Stevens made studies of the relative thickness of the cuticle 

 of the berries of many different varieties to see if this showed any cor- 

 relation to varietal disease resistance. The study gave negative results 

 which were, nevertheless, highly significant and of great importance. 



Weather Observations with Reference to Frost Prediction. (H. J. 

 Franklin in cooperation with the U. S. Weather Bureau). 



(a) Reports of local weather observations made at 8 a.m. (Eastern 

 Standard Time) were made daily by telegraph to the office of the Weather 

 Bureau at Boston. General weather observations were made and recorded 

 at 8 a.m., noon, and 8 p.m. and were reported on a card form to Boston 

 daily. 



(b) Further weather records likely to have a bearing on frost fore- 

 casting were accumulated from observing stations in North Harwich, East 

 Wareham, Carlisle, Holliston and Worcester, as well as the regular cran- 

 berry observing stations at Marstons Mills, South Carver, Norton, Halifax, 

 South Hanson, and Pembroke. 



(c) Studies of observations already recorded yielded important new 

 knowledge on this subject, making possible further definite improvement 

 of the formulae for computing temperature minima. In the formulae thus 

 modified, the dew-point and the reading of the wet bulb thermometer are 

 the significant data mathematically combined. 



(d) Forecasts of minimum bog temperatures were made in the frost 

 seasons at noon and at 7 p.m. (Eastern Standard Time). These forecasts 

 were distributed by the New England Telephone & Telegraph Company 

 as heretofore, the cost of distribution being paid by the Cape Cod Cran- 

 berry Growers' Association. 



Varieties. Dr. Sawyer made hydrogen-ion determinations of the foli- 

 age of many of the cranberry varieties at different times of the day and 

 night and of the growing season. It was thought that this work might 

 show a correlation between pH values and productiveness or disease re- 

 sistance in cranberry varieties; but while the pH of the different varieties 

 showed interesting variations, no very certain correlation of this kind was 

 disclosed. 



DEPARTMENT OF DAIRY INDUSTRY 



J. H. Frandsen in Charge 



A Study of Packaged Ice Cream. (K. E. Wright). This project has 

 continued uninterruptedly during the year. Much work has been done 

 as a check on preliminary conclusions reported in the last Biennial Report. 

 Research work has also been done on several other phases of this prob- 

 lem. Considerable study has been made in an effort to determine just 

 why a maximum drawing temperature of 25.5°F. seems necessary in the 

 case of a 12 per cent fat, 10 per cent serum solids, 15 per cent sugar, 

 and .45 per cent gelatin mix. A study of the rate of cooling samples 

 drawn from the freezer at various temperatures indicated no difference 

 as far as evolution of heat fusion and crystal formation are concerned. 



