l82 REPORTS OF INVEISTIGATIONS AND PROJECTS. 



sequently, during the past year there have been material additions to the 

 laboratory in the shape of such fittings, several of the rooms being now com- 

 pletely equipped and ready for chemical experimentation. The hand-power 

 elevator originally installed was replaced by an automatic electric elevator. 

 While coal-bins and the necessity for taking care of the ashes are elimi- 

 nated by our excellent service from the Harvard Medical School power-house, 

 a vacuum cleaning-apparatus has been established in order to aid in the jani- 

 tor service and to minimize the amount of dust necessarily disturbed by the 

 ordinary process of sweeping. In the original construction of the building 

 a 2-inch vertical pipe was installed with an outlet at each floor. During the 

 past winter a unique vacuum cleaning system of our own design has been 

 installed at a very moderate expense. It consists of a rotary power blower 

 which is so belted to shafting as to be run from the motor commonly used 

 for the circular saw. A special form of water-seal trap for collecting the 

 heavier material is placed between the blower and the stand-pipe. This 

 water-seal trap is provided with appliances for draining off the larger amount 

 of the dirt and flushing with water, and the small amount of dust passing 

 through the trap is forced by the rotary blower through a pipe outdoors. 

 The apparatus is so satisfactory that a small half-inch hose can be carried 

 around the whole building and all dusting done by this means. For the 

 heavier work of cleaning the floors a larger hose with a larger nozzle is 

 employed and practically all sweeping can be done away with. The mainte- 

 nance expense is small and the cost of running negligible. While at first sight 

 it might seem unnecessary to install vacuum cleaning in a building not fitted 

 with rugs and carpets, its practical use in the laboratory for keeping down 

 the dust — dust which would collect on bottles, bacteriological apparatus, 

 etc. — has been fully demonstrated. 



BED CALORIMETER. 



Of the five calorimeters originally planned for the calorimeter laboratory, 

 one was completed in June, 1908, The second was completed in January, 

 1909, and has been used considerably during the winter and spring of 1909. 

 This calorimeter is built on exactly the same principle as the first, but is 

 designed to take subjects lying on a cot and can be used for sick patients as 

 well as normal individuals. The interior is painted with white enamel and 

 is illuminated with a small electric light, the heat developed by the lamp 

 being deducted from the total heat measurements. The apparatus has proven 

 remarkably sensitive and is a valuable addition to our equipment in that it 

 enables us to extend our observations to bed-ridden patients. 



TEMPERATURE RECORDER. 



With a view to ultimately recording automatically as many of the numerous 

 physical and chemical measurements as possible, a specially constructed 

 temperature-recorder has been installed the past winter for the purpose of 

 recording in a curve the differences in temperature of the water entering 



