121 



In the case of the four samples of milk tested by the methods of Patrick 

 and Cochran, the averages for the two methods did not differ in any 

 case by more than ().()(» per cent, from each other, nor by more than 0.09 

 per cent from those obtained by the gravimetric method. With the 

 eleven samples tested by the four methods named and by the gravi- 

 metric the variations were in several cases considerably wider, bnt, on 

 the whole, the resnlts by the different methods agreed very closely. 



"The particular object of these tests was to determine which of these 

 methods could be specially recommended to the dairymen of this State, 

 for accuracy, simi)]icity of the apparatus, and ease of manipulation. 

 Since, as shown, they do not differ essentially in accuracy, the selection 

 of the method to be recommended must be based on the two other points. 

 All things considered, Cochran's method seems to be clearly preferable 

 to the others in these two respects. A full working description of that 

 method is therefore given, essentially as by the author himself in the 

 original article, although in some parts with much more fullness in de- 

 tail, so that with proper care in following directions no one need go 

 amiss." 



Briefly described the method consists in boiling the milk with sul- 

 phuric and acetic acids in a 100 cubic centimeter Erlenmeyer flask, 

 cooling, adding ether, and boiling again until the fat has gathered at 

 the surface and the ether volatilized. The contents of the flask are 

 then transferred to a '' fat measure." This is a flask with the neck nar- 

 rowed and elongated into a graduated measuring tube, and provided 

 with a side tube by which the contents of the boiling flask and hot 

 water are introduced. By adding a proper quantity of water the fat, 

 which rests upon the top of the diluted milk in the fat measure, is 

 brought into the graduated neck and thus conveniently measured. 



Mr. Cocbrau stated iu liis oiigiual article ou this subject, that this method of de- 

 terminiug fat lu milk was tbeu (1889) in use iu upwards of fifty creameries, mostly in 

 Southeastern Pennsylvania, and that with the largest and most improved form of ap- 

 paratus for the heating of the samples, and after becoming perfectly familiar with 

 the manipulation, sixty tests can be made in from two to three hours. 



If scrupulous attention is paid to every detail of the manipulation, as here de- 

 scribed, I think that auy one who is not too clumsy fingered and is accustomed to nice, 

 careful work, can get reliable results with the method after some practice, such as 

 any method would recpiire. But in any case a little training under the instructiou of 

 some one who is perfectly familiar with it would undoubtedly be profitable. 



With any such who can spend a week at Ithaca, arrangements will be made, by 

 special corresi)ondence, for such instruction in the laboratory of the experiment sta- 

 tion. 



Ohio Station, Bulletin Vol. Ill, No. 2, February, 1890 (pp. 58). 



Commercial fertilizers, C. E. Thorne (pp. 17-73). — " Chemical 



or commercial fertilizers were almost unknown in Ohio a dozen years 



ago, outride of a few counties in the extreme eastern and northeastern 



parts of the State. Statistics collected during recent years, however, 



8219— ]^o. 3 3 



