498 The Trials of Cream Separators at Boncaster. 
have all been tlie exhibits of one firm, or at most of two. 
Besides this, in no instance previously have the machines 
been submitted to exhaustive trials ; the power required to 
do the work has rarely been determined or taken into ac- 
count, and awards have been made more as the result of 
general inspection than anything else. Now for the first time 
an attempt has been made to combine the various points at issue. 
For this purpose there were associated as judges, an engineer, 
a practical dairj-farmei", and a chemical expert. Four entire 
days were set apart, previous to the commencement of the Show, 
for the trials. 
It may also be said that though, since the introduction in 
1879 of cream separators into England, great improvements 
have been effected in individual machines, yet the prestige of 
winning a prize at the "Eoyal"was sufficient to attract the 
largest competition that has been brought together, and to 
exhibit the latest novelties, so that the trial was one comprising 
all the machines which are at the present time competing for 
popular favour. 
The present would appear, accoi'dingly, a good opportunity 
for reviewing the history of cream separators in England, and 
for noting briefly the most important modifications that have 
been introduced, and the principal machines tliat have been 
brought forward. 
Po^^■ER ]\Iachines. 
It was at the great International Show of the Royal Agri- 
cultural Society at Kilburn, in 1879, that a machine capable of 
separating the cream from milk by means of centrifugal force 
was exhibited for the first time in England. This was the 
" Laval " centrifugal cream separator, the invention of the 
Swedish chemist. Dr. de Laval. On that occasion it was 
awarded a silver medal, and succeeded in separating 30 gallons 
of milk in 52 minutes. Analyses of the skim-milk showed it 
to have only -22 per cent, of butter-fat left in it, and 93 per 
cent, of the butter-fat of the whole-milk to have been abstracted. 
In a second trial -40 per cent, of butter-fat was found to be left 
in the skim-milk, and in a third and later trial "31 per cent. 
Seeing that the ordinary modes of skimming milk generally 
leave about f per cent, of butter-fat, the advance shown was 
very great. 
The " Laval" separator is figured and described in vol. xv. - 
of the Second Series of this Journal (1879), p. 705, and the 
analytical results obtained with it by the late Dr. "\'oelcker are 
given in vol. xvi. (1880), pp. lGO-2. 
