230 



Cottages for Agricultural Labourers. 



4. Saldanha Bay Guano. — The following are more detailed analyses of 

 four specimens of this variety of guano. The specimens are before de- 

 scribed in Table 10 : — 





Spec. 



78. 



Spec. 79. 



Spec. 80. 



Spec. 81. 





7- 



58 



18-09 



14-40 



12-22 



Organic Matter and Salts of Ammonia . 



21 



69 



15-51 



13-29 



19-64 







63 



•99 



2-26 



-.99 





5G 



99 



58-76 



60-96 



54-82 





3- 



70 



2-23 



1-07 



•57 





2 



61 



•68 



•20 



3-08 





1 



94 



1-31 



4-09 



2-57 







73 



•55 



•72 



•57 







68 



•86 



•20 



•32 



Potash and Soda, and Loss .... 



3 



40 



1-02 



2-81 



5-22 





100 



00 



100-00 



100-00 



100-00 



This table serves to point out that in Saldanha Bay guano, although the 

 potash has not been actually determined, it is, in all probability, in less 

 quantity than in the Peruvian variety. 



5. Nitrogen in Bones. — The estimate in the text is thus derived : bones 

 are supposed to contain 33 per cent, of gelatin, which, according to 

 Scherer, contains 18-32 per cent, of nitrogen; 100 parts of bones will 

 therefore contain about six parts of nitrogen. 



6. Sulphuric Acid, of specific gravity 1*70. — This is the cheapest form 

 in which sulphuric acid can be purchased. When first produced, this acid 

 is diluted with much water, which is driven off by subsequent evaporation. 

 The evaporation is effected, in the first instance, in leaden vessels, and 

 afterwards when the acid, becoming concentrated, begins to act on the 

 lead, it is transferred to vessels of platinum or glass. The expense of this 

 process is so great as materially to enhance the value of the acid. The 

 farmer does not require the acid of 'full strength, and it would be fre- 

 quently far better for him to purchase this dilute acid, which for a certain 

 sum contains a larger amount of acid. The expense of carriage will 

 sometimes interfere with his doing so. 



7. Potash and Phosphoric Acid in Oil-cake. — From several analyses of 

 the mineral ingredients'of oil-cake, I find that 1 ton would contain about 

 43 lbs. of phosphoric acid and 32 lbs. of potash, which at the prices before 

 given would be worth together only about Us. 



XII. — On the Construction of a Pair of Cottages for Agri- 

 cultural Labourers. By Henry Goddard, Architect and 

 Surveyor, of Lincoln. 



First Prize-Essay. 



The leading features of this communication being the plans, 

 specification, and estimate, and as the views of the author are 

 clearly defined therein, it is his intention as concisely as possible 

 to confine his observations to an explanation of them, recording 

 at the outset that no reference has been made to any published 

 work, and that to a long residence in one of the most important 



